Mechta-Afalou and the so-called Mechtoids: Continued!

Part 1 of this subject:
Mechta and Afalou: Do they and the so-called "Mechtoids" constitute a type with the "Cro-Magnon"? [clickable link]

The following are personal notes of the present author, largely made on a discussion...

It is worth noting that, just as Howell's collection falls short of representing a broader spectrum of regional inter-African variability, so is Groves' even smaller selection from this collection for comparative analysis, using the select "contemporary" groups as a basis for comparing the late Paleolithic/early Holocene specimens. This needs to be taken into consideration when recalling on Groves' claims about the so-called "caucasoid" and "negroid" intra-African geographical transition in the Paleolithic and how this divide supposedly shifted, with the so-called northern "negroid" territorial limit having shifted southward to some extent in the post-Paleolithic periods, in particular - the present.

Recalling Groves,...

a wide sparsely populated region whose people are intermediate morphologically between “Caucasoid” and “Negroid”. While the late and terminal Pleistocene populations of northern Africa were noticeably more robust than their present-day descendants (as were those of Europe), like them they were differentiated into more northerly “Caucasoid” and more southerly “Negroid” morphologies. **Yet the transition between these two geographic forms was much further north in the terminal Pleistocene than today**; the terminal Pleistocene Nubians and the Asselar skull are as “Negroid” as are the modern Teita of Kenya; the intermediates were the people of Afalou-bou-Rhummel in Algeria.

Going onto Groves' Factor analysis

Click on the image for greater resolution

 

The means of selected modern samples from the dataset of Howells (1973) were entered along with those of the fossil samples into a factor analysis to assess the interrelationships of the samples.

The males of the Afalou, Taforalt and Cro-Magnon samples lie far to the right on the diagram (Fig. 4), on factor 1, followed by Nubia male, Asselar, Cro-Magnon female, and Norse and Egypt male; to the left (scoring low on factor 1) are Dogon and Teita males, and the females of the remaining samples. On factor 2, Cro-Magnon, Taforalt, Norse and Egypt score positively, and Afalou and the sub-Saharan and Nubian samples score negatively.

Factor 1 represents robusticity, factor 2 represents the sub-Saharan/Caucasoid contrast. The Caucasoid populations (Egypt, Norse, Cro-Magnon) score positively on factor 2, the sub-Saharan Teita score negatively. The modern Dogon (Southern Mali) samples are intermediate. The fossil Nubians who were described as being Mechtoid score strongly negative, as does the Asselar skull (Central Mali). What is especially interesting is that Afalou also scores negatively, if only slightly; it occupies the same morphological position as do the modern Dogon.

Present author's take: Of note, is that in the figure in question, the Dogon which Groves' analysis deems "intermediate", it just so happens that the male specimen fell on the "positive" end, while the female counterpart on the "negative" end. Meanwhile, as claimed in Groves' notes above, the Nubian fossils which have been described as being "Mechtoid", report "negatively". That Groves considers the Dogon the modern "intermediate" specimen between two so-called "geographic morphologies" of "caucasoid" and "negroid" would be interesting to anyone who is familiar with the Dogon people.

An old New York Times piece on the Afalou...

"The discovery of a new race of neolithic man at Afalou, Algeria, with strange resemblances to the Natufians recently found in Palestine, was announced by the french scientists, Marcellin Boulle and Heri Vallois. Like the Natufians, these hitherto unknown people had some of their incisor teeth knocked out in early life and their limb bones were strong. Their discoverers were unable to connect them with either the Neanderthal man or the Negro or with mediterranean types of modern times."

What's interesting about this piece, is that it makes note of the "resemblances" between the Natufians and the Afalou. In a few years of discovery, in the 1930s, Natufians were then deemed by certain researchers of the time to have "negroid" tendencies. This was before any link between Natufians and early farming practices was made. Taking this into consideraton, one has to pause and think, when the New York time piece says:

"Their discoverers were unable to connect them with either the Neanderthal man or the Negro or with mediterranean types of modern times."

In relation to the above: Perhaps, the "generalized" modern type?!

Either the discoverers didn't have the credentials necessary to make educated comparative observations, or they knew something they didn't want to share with the reading public or their target audience.

It is not certain here what date the NY times piece was released or the full report, but it could be possible [aside from not having yet fully studied the specimens for finer details] that the claim for not being able to draw a connection with the said “types”, has something to do with the notion that the Afalou supposedly resemble or have affinities with the Upper European specimen named Cro-Magnon [who have been viewed as European ancestors]. Remember that Elliot Smith denied any possible ties between the Natufians and the “Negro” type(s), even though other Eurocentric scholars of his time at least acknowledged traits which they associated with the “Negro” type(s). If Afalou was deemed to have been “Negroid”, while resembling the Cro-Magnon, then this would be tantamount to saying that European ancestors, as Cro-Magnons, were “Negroid” or had “Negroid” tendencies as well. Would the Eurocentric scholars of that era have gone that far? The present author believes one can draw his/her own conclusions on this.

The Cro-Magnons don’t tie with contemporary coastal Berbers, as Brace points out, while Briggs and Groves’ seem to imply that the Afalou are not devoid of the so-called “Negroid” traits, painting them as “Intermediate” specimens. Groves’ comparison of the Afalou with the Dogon as being “intermediate”, is particularly interesting, given that we have an idea of what the Dogons look like.

Furthermore, Groves tells us...

“Arambourg et al. (1934) referred to these robust North Africans as the “Mechta-Arbi race”; Ferembach (1962) as Ibero-Maurusians, or Epipalaeolithic, after their lithocultural association. Briggs (1955) divided the Afalou and other samples into four “types” (Palaeomediterranean, African Mediterranean, African Alphine, and true Mechta-Afalou). Anderson (1968) considered them far too homogeneous to warrant this treatment, and indeed Briggs’s analysis is in the typological tradition that held sway up until about 1940, but was thereafter increasingly discarded” — C. Groves, 1999.

Briggs must have felt that he saw enough variations between the North African samples, so as to warrant the said four "types". But as Groves points out, others later, felt that the samples were less heterogeneous to warrant Briggs' kind of labeling, into four African "types". The legitimacy of a single type to which the above specimens, including the European Cro-Magnons, supposedly belong, will be re-visited shortly.

Groves goes onto say:

Exactly the same process of gracilisation seems to have taken place in this region; Carlson and Van Gerven (1977) attributed it to a change in masticatory function, associated with the processes leading to the adoption of agriculture. The largest collection, from Tushka and Sahaba, was described by Anderson (1968); he considered them in the context of “Negroid origins”, but ended by concluding that they are strongly resemble the “Maghrebian Cromagnoids”, as he called Mechta-Afalou populations, but considered that they were “half-way to ‘Negroidization’”, and demonstrated the late derivation of sub-Saharans from Caucasoids

Briggs, as pointed out earlier, felt that the North African samples, the African Mediterraneans, weren't devoid of "Negroid" traits, but acquired these from "Negro" females on their migration path. Anderson on the other hand, interestingly uses "Negroidization", meaning that the originally "Caucasoid" groups evolved into the "Negro" [Sub-Saharan as Groves put it] type. "Caucasoids" spawning "Negroids"; one wonders where that has been heard before?

Alternatively, how about the "Caucasoidization" [we all know why this term doesn't exist] of the original "Negroids"? Funny business! It should be obvious to anyone by now familiar with Out-of-Africa hypothesis of modern human origins, the overwhelming ongoing scientific consensus, that the idea of "negroids" evolving from "caucasoids" is utter descredited nonsense. Moreover assessment of the distribution pattern of human skin pigmentation alleles corresponds well with the Out-of-Africa hypothesis, as do most other genetic monophyletic units; links to that topic:

Skin pigmentation gene alleles [clickable link]

Skin pigmentation gene alleles Part 2 [clickable link]

Revisiting the issue of a "type" to which "Mechtoids" supposedly to belong...

“Arambourg et al. (1934) referred to these robust North Africans as the “Mechta-Arbi race”; Ferembach (1962) as Ibero-Maurusians, or Epipalaeolithic, after their lithocultural association. Briggs (1955) divided the Afalou and other samples into four “types” (Palaeomediterranean, African Mediterranean, African Alphine, and true Mechta-Afalou). Anderson (1968) considered them far too homogeneous to warrant this treatment, and indeed Briggs’s analysis is in the typological tradition that held sway up until about 1940, but was thereafter increasingly discarded” — C. Groves, 1999.

Recap: Briggs must have felt that he saw enough variations between the North African samples, so as to warrent the said four "types". But as Groves points out, others later, felt that the samples were less heterogenous to warrent Briggs' kind of labeling, into four African "types".

Let's examine this:

Recalling the present author's take: The specimens previously placed under the ‘Mechta-Afalou’ actually don’t represent a “type”, but an assortment of specimens that share affinities in some respects, and not so much so in others. Even “robusticity’, which it seems has been seized by some to justify classification into a “type” or “categorization”, varies.

...which is not incompatible with Brace's observation on "Cro-magnon" as well:

Paul Broca himself had promoted the view that the Basques represent the continuing existence of the kind of Upper Paleolithic population excavated at the Cro-Magnon rock shelter in the village of Les Eyzies in the Dordogne region of southwestern France in 1868 (38-40). Shortly thereafter the “old man” -“le vieillard” -found in that rock shelter was elevated to the status of typifying a whole “Cro-Magnon race” regarded as ancestral to not only the Basques but also the aboriginal inhabitants of the Canary Islands (37, 41-44)…

When the Basques are run with the other samples used in Fig. 1, they link with Germany and more remotely with the Canary Islands. They are clearly European although the length of their twig indicates that they have a distinction all their own. It is clear, however, that they do not represent a survival of the kind of craniofacial form indicated by Cro-Magnon any more than do the Canary Islanders, ***nor does either sample tie in with the Berbers of North Africa*** as has previously been claimed (37, 44-45).
…

To test the analysis shown in Fig. 3, Cro-Magnon, represented by the x in Fig. 4, was removed from the European Upper Palaeolithic sample and run as a single individual. **Interestingly enough, Cro-Magnon is not close to any more recent sample**.

Clearly Cro-Magnon is not the same as the Basque or Canary Island samples. Fig. 4 plots the first and second canonical variates against each other, but that conclusion is even more strongly supported when canonical variate 3 (not shown here) is plotted with variate 1. If this analysis shows nothing else, **it demonstrates that the oft-repeated European feeling that the Cro-Magnons are “us” (46) is more a product of anthropological folklore** than the result of the metric data available from the skeletal remains... — Brace et al. 2005

...and in response to analyzing the following Groves' piece taken from his publication, “The terminal Pleistocene and early Holocene populations of northern Africa”, 1999:

To the southeast, further cranially robust remains have been described from Nubia, on the Egyptian-Sudanese border (Anderson 1968; Wendorf 1968a, b; Carlson and Van Gerven 1977). Exactly the same process of gracilisation seems to have taken place in this region; Carlson and Van Gerven (1977) attributed it to a change in masticatory function, associated with the processes leading to the adoption of agriculture. The largest collection, from Tushka and Sahaba, was described by Anderson (1968); he considered them in the context of “Negroid origins”, but ended by concluding that they are strongly resemble the “Maghrebian Cromagnoids”, as he called Mechta-Afalou populations, but considered that they were “half-way to ‘Negroidization’”, and demonstrated the late derivation of sub-Saharans from Caucasoids.

There are therefore a number of hypotheses about these terminal Pleistocene samples, which we propose to test this paper:

1. That the Mechta-Afalou populations are a generalized “robust” Homo sapiens population (Lahr 1994), or alternatively that they are robust because they are “Cromagnoid” in morphology, i.e. resemble the Upper Paleolithic populations of Europe (Ferembach 1985, Brauer and Rimback 1990)

Groves' results, with regards to 'robusticity':

Lahr’s (1994) hypothesis, that the Maghrebian samples resemble the Cro-Magnons, is true as far as the males are concerned, but not for the females. Cro-Magnon females are robust, as are Co-magnon males; Taforalt females, however, are not so robust.

As far as morphology is concerned, Groves' approach to discriminant analysis yields:

The discriminant analysis shows that the Nubian scatter is so wide that it is some of the Nubian males, rather than any of the Maghrebian ones, that are Cromagnon males’ nearest neighbors. The nearest neighbour of the Cromagnon females, however, is the sole Afalou female.

The frequency if occurrence of the horizontal-oval form of the mandibular foramen compares more closely to the Cro-Magnons in the Nubian than in the Maghrebian sample. In the Maghreb sample, it occurs in 1/15, ie. 6.7%, but in the Nubians in 4/18, that is 22.2% (in the Sahaba sample by itself, 4/14, or 28.6%).

According to Frayer (1992), in 38 late upper Paleolithic specimens (approximately contemporary with the present samples) this form occurs in 5.3%, although in 9 Early Upper Paleolithic specimens it was seen in 44.4%.

North African "Mediterraneans" [now defunct] and the so-called Mechtoid North African specimens were just part of early attempts of European researchers to seek a "European-like" component in north Africa, which in the case of the "Mechtoid" types, took the guise of using the so-called Cro-magnon specimen as the model to build the comparison around. Some of these researchers saw cranio-morphological resemblances between the so-called "Mechtoid" African specimens and the European "Cro-Magnon" specimen, as the present author has noted earlier, yet were not totally oblivious to the differences as well, which prevented them calling the African examples as plainly "Cro-magnons"...just as there were attempts to associate what was dubbed "African Mediterraneans" with the other so-called "Mediterranean" specimens, who just so happened to also belong to this one big happy family of "caucasoids".

Interestingly, as noted earlier herein, there had been some linkage drawn between the so-called "Mechtoid specimens" , i.e. the Mechta-el-Arbi, the Afalou-bou-Rhummel, the Taforalt specimens and possibly the likes of the Jebel Sahaba specimens of the Nile Valley, with what were dubbed as "Mediterranean racial types":

Recap: "The Negroid increment of which there is evidence in some of our Northern Neolithic Series, notably Kef-el-Agab 1 and Troglodytes 1, may have well come in the same way from the South to *add* to the *already* slightly **Negroid Hamitic cast** of the African Mediterraneans and of their **partial derivative**, the Mechta-Afalou Type." — Briggs

In another recap, Briggs goes onto to note that, again with regards to the so-called "Mediterranean racial type":

"...Type B which fits, in all essential respects, the usual definition of the Mediterranean racial type, but sometimes shows also certain morphological peculiarities commonly known as "Boskopid," as well as Negroid features among females. Type B therefore was classified as African Mediterranean...It may have well acquired its "Boskopid" traits on the road, near the headwaters of the Nile, and kidnapped a few Negro or heavily Negroid women on its way west before turning northward into Northwest Africa. The peculiar characteristics of such women could have been restricted largely to females, at least for a time, by artificial selection in the form of preferential mating." - Source: Briggs, Stone Age Races of Northwest Africa, pgs 81,89.

So, apparently both the so-called African "Cro-Magnoid-like" specimens [aka the "Mechtoid"/"Mechta-Afalou" type] in no way actaully represented a single cranio-morphometric type [wherein the "Cro-magnon" is used as the model of morphology], as the notes herein bring to light; the Maghrebian specimens are clearly distinguished from the so-called Mechtoid examples found in the Nile Valley, like the Sahaba specimens. We also know that the Megrebian examples, not in any way to be associated with contemporary northwest Africans, are clearly distinguished from the "Cro-Magnon" of Europe [seemingly acknowleged even in the terming of the "North African Cro-Magnoids" appellation—"iod" implying "likewise but not quite [what is the model]"], as demonstrated above in Groves' discriminant analysis where even some so-called "Nubian" specimens actually clustered closer to the European "Cro-magnoid specimens" than the Maghrebian examples. Yet, in Groves factor analysis, which he uses as his supposed gauging tool to term the "caucasoid" or "negroid" inclination of the specimens in question, the "Nubian" specimens were supposedly inclined towards the so-called "Negroid" tendencies, while the European "Cro-magnoid" specimens and the Maghrebian Taforalt series, to put it in Groves' terms:

On factor 2, Cro-Magnon, Taforalt, Norse and Egypt score positively, and Afalou and the sub-Saharan and Nubian samples score negatively.

...where essentially groups who scored "positively", were implied to have an inclination towards the so-called "caucasoid" tendencies...but it gets interesting, in continuing with Groves' claims:

Factor 1 represents *robusticity*, factor 2 represents the **sub-Saharan/Caucasoid** contrast. The Caucasoid populations (Egypt, Norse, Cro-Magnon) score positively on factor 2, the sub-Saharan Teita score negatively. The modern Dogon (Southern Mali) samples are intermediate. The fossil Nubians score strongly negative, as does the Asselar skull (Central Mali). What is especially interesting is that Afalou also scores negatively, if only slightly; it occupies the same morphological position as do the modern Dogon.

Present author's take: So [as already noted yet again], a Maghrebian specimen, namely the Afalou specimens, occupy the same position as the "modern Dogon" [although a Dogon male scores positively], which is the "intermediary" position? Well, we know what the modern Dogon generally look like...but if anything, at the least, this is yet indication that even the Maghrebian series don't all converge into a single cranio-morphometric "type".
[Note: Norse, Egypt, Dogon and Teita are supposed to be relatively modern examples from Howells' database — 1973]

Just as the so-called "Cro-Magnoid" actually fails to show a single morphological type, so does the so-called "Mediterranean racial type", as can be seen from the pains at which various researchers were trying to reconcile the seemingly so-called "Boskopid" and "Negroid" traits in "African Mediterranean" specimens with the basic ideology behind the so-called "Mediterranean racial type". Obviously the so-called "African Mediterraneans" notably differed from their so-called "Mediterranean" counterparts from across the other side of the Mediterranean sea, prompting these researchers to explain away what Briggs dubs as "morphological peculiarities". Now of course, as far as as the present author can tell at this point, we are not offered any specific extra-cranio-morphometric biological evidence that such "morphological peculiarities" were simply acquired from "miscegenation" between "African Mediterraneans" [whom by implication, were presumably devoid of such "morphological peculiarities" initially] and other groups which were presumably 'typified' by the said "morphological peculiarities", as opposed to being either relics or indicators of the natural micro-evolution of the said "African Mediterraneans". Of the present author's estimation, it seems that the attempt to draw up a type, around the Cro-Magnon model, as is the case to draw up a "Mediterranean racial type", is nothing more than futile Eurocentric attempt to create "types", more likely 'racial types', in which European specimens are presented as models, and extend this European family type into North Africa...as though an attempt to make North Africa into an extension of Europe, as opposed to its being factually [and objectively] part of Africa both geographically and biologically. The bio-anthropological goal of Eurocentric doctrine has historically been to create pseudo-scientific racial types or their subtly transparent "euphemisms", that will extend the associated "European-affiliated" family as much as possible into areas of interest. The pains at which Euro-researchers sought to create "types" around 'Euro-centered' or 'Euro-affiliated' models, can be exemplified in that seen in the following:

recap: “Arambourg et al. (1934) referred to these robust North Africans as the “Mechta-Arbi race”; Ferembach (1962) as Ibero-Maurusians, or Epipalaeolithic, after their lithocultural association. Briggs (1955) divided the Afalou and other samples into four “types” (Palaeomediterranean, African Mediterranean, African Alphine, and true Mechta-Afalou). Anderson (1968) considered them far too homogeneous to warrant this treatment, and indeed Briggs’s analysis is in the typological tradition that held sway up until about 1940, but was thereafter increasingly discarded” — C. Groves, 1999.

Translated source: Para conocer al hombre: Homenaje a Santiago Genovés a 33 años como investigador en la UNAM, by Santiago Genovés, Universidad Autónoma de México Instituto de Investigaciones Antropológicas, 1990.

Speaking of which—with regards to the Afalou‘s being “neither Negro or San”, on the other hand, from Groves, to repeat...

factor 2 represents the **sub-Saharan/Caucasoid** contrast. The Caucasoid populations (Egypt, Norse, Cro-Magnon) score positively on factor 2, the sub-Saharan Teita score negatively. The modern Dogon (Southern Mali) samples are intermediate. The fossil Nubians score strongly negative, as does the Asselar skull (Central Mali). What is especially interesting is that Afalou also scores negatively, if only slightly; it occupies the same morphological position as do the modern Dogon.

Recap: So, a Maghrebian specimen, namely the Afalou specimens, occupy the same position as the "modern Dogon" [although a Dogon male scores positively], which is the "intermediary" position? Well, we know what the modern Dogon generally look like...but if anything, at the least, this is yet indication that even the Maghrebian series don't all converge into a single cranio-morphometric "type".

[Note: Norse, Egypt, Dogon and Teita are supposed to be relatively modern examples from Howells' database — 1973]

The discriminant analysis shows that the Nubian scatter is so wide that it is some of the Nubian males, rather than any of the Maghrebian ones, that are Cromagnon males’ nearest neighbors. The nearest neighbour of the Cromagnon females, however, is the sole Afalou female. - Groves

What seems to be at work here? It looks to be what the present author calls the "Spanish crania" syndrome:

"race classification of all individuals in this sample using the Forensic Data Bank option. Of the 95 individuals, 42 (44 percent) were classified as white, 35 percent as black, 9 percent as Hispanic, 4 percent as Japanese, 4 percent as American Indian, and the remaining three individuals as Chinese and Vietnamese" - Ubelaker et al., Application of Forensic Discriminant Functions to a Spanish Cranial Sample, 2002 [see: Cranio-morphological Variation]

The above pre-historic "Nubian" crania display a phenomenon not uninterestingly distinct from their more modern counterparts:

“If Fordisc 2.0 is revealing genetic admixture of Late Period Dynastic Egypt and Meroitic Nubia, then one must also consider these ancient Meroitic Nubians to be part of Hungarian, part Easter Islander, part Norse, and part Australian Aborigine, with smaller contributions from the Ainu, Teita, Zulu, Santa Cruz, Andaman Islands, Arikara, Ayatal, and Hokkaido populations. In fact, all human groups are essentially heterogeneous, including samples within Fordisc 2.0. Using Fst heritability tests, Relethford (1994) demonstrated that Howells’s cranial samples exhibit far more variation within than between skeletal series. There is no reason to assume that the heterogeneity of the Late Period Dynastic Egyptian population exceeds that characterizing our Nubian sample. This heterogeneity may also characterize the populations in the Forensic Data Bank; Fordisc 2.0 classified the Meroitic Nubians not as either all black or all white but as black, white, Hispanic, Chinese, Japanese, and Native American.” - Williams et al. 2005 [again see: Cranio-morphological Variation]

Such is the result of preconceived attempts to force superficial population variations to undeviating non-overlapping socio-ethnic or "racial" types.

Synopsis: The European inclination to see themselves in North Africans, a region home to one of the most glorified highly-structured social complexes of antiquity — notable examples being Kemet and Kush, is what this whole "Mechtoid" deal is about; in this case, the Cro-Magnon was the Eurocentric template of choice. However, as Brace noted, nothing about the cranio-facial morphology of the contemporary Imazighen suggests a link to Cro-Magnons. And indeed, genetics backs him on this point as well.

As we have seen, even the attempt to relate prehistoric North Africans to European counterparts has virtually failed, as the Mechtoid concept shows; the specimens designated as such neither display a single cranio-morphological type nor robusticity, as the term "Mechtoid" implies. Heck, they are all not even dated to the same time frames. So, it is nothing more than the Eurocentric concept, as Brace again noted, to use "Cro-Magnon" and say that the "Cro-Magnon represents us"...with the "us" meaning "European". Brace characterized this belief as being more of an anthropological "folklore" rather than fact. In fact, Brace says that the Cro-Magnon doesn't tie with any of the contemporary European specimens he studied. So again, the Mechtoid concept and its supposed relationship with Cro-Magnon, is nothing more than another Eurocentric way of trying to relate North Africa to Europe...essentially a *wishful* desire to see north Africa as more an extension of Europe than the actual continent [Africa] its attached to. However, it fails miserably not only for reasons just noted, but also from the fact that none of the so-called Mechtoid specimen 'types' covered here have ever been located in Europe itself.

12-repeat allele at DYS392 microsatellite of certain PN2 clades, including E-M78.

Update!

Getting back to the point raised earlier about the rare 12-repeat allele at DYS392 by Semino et al...

It is interesting that both E-P2* and E-M35* and their derivatives, E-M78 and E-M123, exhibit in Ethiopians the 12-repeat allele at the DYS392 microsatellite locus, an allele scarcely seen (Y-Chromosome STR Database), especially in other haplogroups and other populations (A.S.S.-B., unpublished data). 

In addition, the Ethiopian DYS392-12 allele is usually associated with the unusually short DYS19-11 allele, which is typical of this area. These findings are not easily explained. One possible scenario is that an ancient differentiation of the E-P2 haplogroup occurred in loco (East Africa). However, this also implies a low mutability of the associated microsatellite motif (DYS392-12/DYS19-11). Alternatively, the microsatellite motif may be due to homoplasy.The first scenario is more likely, since this unique microsatellite haplotype occurs in E-P2*, E-M35*, and E-M78 but is almost *absent in all other haplogroups and populations*.

In addition, the high stability of the DYS392 locus (Brinkmann et al. 1998; Nebel et al. 2001) and of the shorter alleles of DYS19 (Carvalho-Silva et al. 1999) has been reported elsewhere.

Moreover, the observation that the derivative E-M78 displays the DYS392-12/DYS19-11 haplotype suggests that it also arose in East Africa. This is illustrated by the microsatellite network (fig. 3, shaded area), which reveals that the Ethiopian branch harboring DYS392-12 is not shared with either Near Eastern or European populations. — Semino et al. Origin, Diffusion, and Differentiation of Y‐Chromosome Haplogroups E and J, 2004.

To which the present author responded...

The Ethiopian sample may not share the said allele with those populations mentioned, including the northwest African samples as far as I can tell, but it does share the said allele with the Senegalese sample [see fig. below], which would suggest that the Senegalese M78 derivative didn’t come from interaction with its northwest African neighbors; rather, they may well be relics of ancient migrations from east to west.

Cruciani et al. in their 2007 publication, Tracing human male movements in northern/eastern Africa and western Eurasia: new clues from Y-chromosomal haplogroups E-M78 and J-M12, had this to say about the 12-repeat allele in question:

“An eastern African origin for this haplogroup was hypothesized on the basis of the basis of the exclusive presence in that area of a putative ancestral 12-repeat at the DYS392 micro satellite , found in association with E-M78 chromosomes (Semino et al. 2004). North-eastern African populations were not represented in that study.

In order to test this hypothesis, we analyzed for DYS392 a geographically widespread subset of the E_M78 chromosomes here identified. We observed that the DYS392 12-repeat allele is associated with the majority of the chromosomes belonging to the north-eastern African E-V12* (15 out of 18) and to the eastern African E-V32 (21 out of 23), with about half (9 out of 21) of the E-V22 chromosomes (both in eastern and north-eastern Africa), with a few of the European E-V13 (2 out of 23) and with some north-African E-V65 (3 out of 16) chromosomes.

These findings show that the DYS392 12-repeat allele is common in different regions characterized by high frequencies of E-M78, and suggest that it was most likely generated by multiple mutation events occurring in different UEP-defined sub-haplogroups. Thus, the DYS392 allele distribution is not informative to infer the place of origin of E-M78 chromosomes.”

Cruciani et al. point out that Northeast Africa wasn't represented in the 2004 Semino et al. study, presumably to emphasize the point that its detection therein would have shown that the 12-repeat allele in question wasn't confined to sub-Saharan east Africa, particularly Ethiopia. It is certainly true that northeastern Africa was not represented, but in fact, a close examination of Semino et al.'s 2004 study, shows that the 12-repeat allele wasn't confined to sub-Saharan east Africa; it makes single or very low appearances in the "Near Eastern" and "European" samples, and interestingly none in north African [sans northeast Africa] samples.

Cruciani et al. on the other hand, did detect the 12-repeat allele in north African [sans northeast Africa], but still in relative low frequency (3 out of 16). The same applies to their findings in European samples, where it appears to be yet rarer than that of the north African samples. Considerable frequency is however noted in their northeast African sample, and consistently, in sub-Saharan east African samples. So, even going by Cruciani et al.'s findings, the greater distribution of the 12-repeat allele in eastern Africa in general, would argue for its introduction from eastern Africa.

Cruciani et al. reckon that simply because the 12-repeat allele is not confined to east Africa, it therefore doesn't allow one to infer the place of origin of E-M78 chromosomes. This ignores the point just made about its relatively rare occurrence outside of east Africa. Cruciani et al. reach this conclusion on the understanding that the 12-repeat allele's appearances in distinct sub-clades invokes homoplasy or parallel mutational events, and indeed, Semino et al. 2004 did not rule out that possibility, but unlike Cruciani et al. they took additional material into consideration:

—1) "It is interesting that both E-P2* and E-M35* and their derivatives, E-M78 and E-M123, exhibit in Ethiopians the 12-repeat allele at the DYS392 microsatellite locus, an allele scarcely seen..."

So while there is notable presence of 12-repeat allele bearing E-M78 chromosomes in northeast Africa as well, only in sub-Saharan east Africa does one come across not only considerable frequencies of E3-P2 [PN2 clade], but also the more immediate precursor of E-M78, i.e.—E-M35*, which bear this 12-repeat allele. As far as the present author can tell at this point, pending introduction to studies that suggest otherwise, the ensemble of at least three different PN2 macro-clade—including the ancestral ones—bearing the said 12-repeat allele, only occures in sub-Saharan east Africa. Case in point:

"...first scenario is more likely, since this unique microsatellite haplotype occurs in E-P2*, E-M35*, and E-M78 but is almost *absent in all other haplogroups and populations*."

—2) "One possible scenario is that an ancient differentiation of the E-P2 haplogroup occurred in loco (East Africa). However, this also implies a low mutability of the associated microsatellite motif (DYS392-12/DYS19-11)...

In addition, the high stability of the DYS392 locus (Brinkmann et al. 1998; Nebel et al. 2001) and of the shorter alleles of DYS19 (Carvalho-Silva et al. 1999) has been reported elsewhere."

So again, while not ruling out independent parallel microsatellite mutational events across different PN2 clades, the repeat occurrence of the 12-repeat allele across different PN2 clades, including the ancestral ones, coupled with the possibility of "low mutability", which translates into "high stability" of the locus in question, indicates that the 12 repeat could well have also been inherited from a precursor PN2 clade(s). If the latter is the case, certainly sub-Saharan East Africa as the likely place of origin for the allele, can be put forward as a strong argument. And in getting back to the appearance of this allele in sub-Saharan or Sahelian west Africa, in the Senegalese sample for instance, would tend to favor an east African origin at some point in history, rather than as a remnant of interactions with coastal northwest Africans, where the allele is rare, even going by Cruciani et al.'s findings.

Initially posted here:

http://exploring-africa.blogspot.com/2008/02/nry-haplogroup-e3a-proposing-its.html

Mechta and Afalou: Do they and the so-called "Mechtoids" constitute a type with the "Cro-Magnon"?

The “Mechta” have been characterized as African based “Cro-Magnon types”. Obviously enough morph-metric distinctions have been observed between the “Mechta” and the “Cro-Magnon” specimens, so as to assign them in distinct but related groups; however, does the “Mechta”, and ultimately “Cro-Magnon”, really represent a bio-anthropological “type”? Does it persist today? These are the questions that will be explored herein.

Let’s start this journey of brief exploration with an extract from Brace et al. 2005:

The North African Epipalaeolithic sample was made based on specimens from Afalou and Taforalt in Morocco [Mechta-Afalou (?)]…

Paul Broca himself had promoted the view that the Basques represent the continuing existence of the kind of Upper Paleolithic population excavated at the Cro-Magnon rock shelter in the village of Les Eyzies in the Dordogne region of southwestern France in 1868 (38-40). Shortly thereafter the “old man” -“le vieillard” -found in that rock shelter was elevated to the status of typifying a whole “Cro-Magnon race” regarded as ancestral to not only the Basques but also the aboriginal inhabitants of the Canary Islands (37, 41-44)... 

When the Basques are run with the other samples used in Fig. 1, they link with Germany and more remotely with the Canary Islands. They are clearly European although the length of their twig indicates that they have a distinction all their own. It is clear, however, that they do not represent a survival of the kind of craniofacial form indicated by Cro-Magnon any more than do the Canary Islanders, nor does either sample tie in with the Berbers of North Africa as has previously been claimed (37, 44-45). …

To test the analysis shown in Fig. 3, Cro-Magnon, represented by the x in Fig. 4, was removed from the European Upper Palaeolithic sample and run as a single individual. Interestingly enough, Cro-Magnon is not close to any more recent sample. Clearly Cro-Magnon is not the same as the Basque or Canary Island samples. Fig. 4 plots the first and second canonical variates against each other, but that conclusion is even more strongly supported when canonical variate 3 (not shown here) is plotted with variate 1. If this analysis shows nothing else, it demonstrates that the oft-repeated European feeling that the Cro-Magnons are “us” (46) is more a product of anthropological folklore than the result of the metric data available from the skeletal remains...

That said, more extracts to examine…

From Andrea Byrnes' website, we are told:

A child burial was found at Taramsa-1 dating to this time (c.55,000BP): “The poorly preserved bones were those of a subadult ‘anatomically modern human’ similar in appearance to the Mechtoid populations of the north African Epipalaeolithic. The position of the body, as well as the depth of the pit in which it was found . . . suggest that the child had not died in this location but had been deliberately brought here to be buried” (Midant-Reynes 1992/2000 p.37).

And then...

"Gebel Sahaba produced 59 skeletons, all semi-contracted on their left sides (head orientated east, facing south). The graves are simple pits with sandstone capstones. Associated tools date the site to around 12,000 BP. 24 of the individuals appear to have met with **a violent and unnatural death** (chert points were embedded in bones and skulls, and severe cut-marks appear on some of the bones. Women and children represent around 50% of the cemetery. The features are mechtoid or “mechta-afalou” (Phillipson 1985, 1993, p.34). Dating relies mostly on typological associations. The toolkit includes burins, flakes, backed flakes, bladelets, end-scrapers and geometric microliths, and is very similar to and usually associated with the Qadan at around 1200 BP."

Present author's take: Interesting...the proposed fate of those "Mechtoid" remains, i.e., violent death in the Nile Valley region! Could this make a case for a near extinction via sustained violence against these groups? Surely, as anatomically modern humans, they must have had something going for them, to avoid this [extinction via violence brought to bear by other ethnic groups] from happening; e.g., "at least" retreat to some other location, no? Even then, would this necessarily apply to populations in Western Africa, where relatively wider distribution of specimens tagged as “Mechta“ or “Mechtoids“ were recovered?

Continuing with examination of pieces of information from various sources:

Midant-Reynes informs us about an Epipaleolithic Fayum specimen..."The body was that of a 40 year old woman with a height of 1.6 meters, who was of a more modern racial type than the classic "Mechtoid" of the Fakhurian culture, being generally gracile, having large teeth and thick jaws bearing some resemblance to the modern "negroid' type." — B. Midant-Reynes, The Prehistory of Egypt, Pg 82.

Raises the question of the notwithstanding recognition of the Mechta-Afalou specimen as anatomically modern types, whether the comparison of their "modernity" with other anatomically modern human variants lies in the "robusticity" of the remains, or the age, or both!

From Briggs, notwithstanding his obvious prejudiced tone, we have:

"The Negroid increment of which there is evidence in some of our Northern Neolithic Series, notably Kef-el-Agab 1 and Troglodytes 1, may have well come in the same way from the South to add to the already slightly Negroid Hamitic cast of the African Mediterraneans and of their partial derivative, the Mechta-Afalou Type."

...and what are we told about these so-called "African Mediterraneans", well...

"...Type B which fits, in all essential respects, the usual definition of the Mediterranean racial type, but sometimes shows also certain morphological peculiarities commonly known as "Boskopid," as well as Negroid features among females. Type B therefore was classified as African Mediterranean...It may have well acquired its "Boskopid" traits on the road, near the headwaters of the Nile, and kidnapped a few Negro or heavily Negroid women on its way west before turning northward into Northwest Africa. The peculiar characteristics of such women could have been restricted largely to females, at least for a time, by artificial selection in the form of preferential mating."

Source: Briggs, Stone Age Races of Northwest Africa, pgs 81,89.

Note: The so-called "Boskopid" is supposedly related to the South African Khoisan groups.

From Briggs' claims, it would appear that the Mechta-Afalou, just as their supposed "partial" ancestors, i.e., the African Mediterraneans, were NOT devoid of traits typologically attributed the "Negro".

Keeping in mind the likes of the Nazlet Kharter [see extract below]...and the earlier snippets the present author posted on finds of Upper Paleolithic/Epipaleolithic "Mechtoid" remains in the Upper Nile Valley [recalling that, the burial site of at least one specimen dated back to 55,000 BP, while that of several more other specimens dated to a much later period, i.e., 12,000 BP], it would be interesting to see where these "Mechtoid" groups fit in, in terms of chronology of their appearance in the region and social status during those time frames.

From Keita, we have:

"Descriptions and photographs of late Paleolithic remains from Egypt indicate characteristics which distinguish them clearly from their European counterparts at 30,000 and 20,000 years BP (cf. Thomas 1984; Stewart 1985; Angel and Kelly 1986). These distinguishing characteristics, commonly called "Negroid," are shared with later Nile Valley and more southerly groups. It is not important to label "Negroid," only to note that they are shared with a wide range of African populations. Epipaleolithic "mesolithic" Nile Valley remains have these characteristics and diverge notably from their Maghreban and European counterparts in key cranio-facial characteristics (see comments in Keita 1990) although late Natufian hunters and early Anatolian farmers (Angel 1972) shared some of these traits, suggesting late Paleolithic migration out of Africa, as supported by archeology (Bar Yosef 1987). Lumping the epipaleolithic remains of the Nile Valley and even those from the Maghreb, into one group has little to support it..." — Keita, Studies and Comments on Ancient Egyptian Biological Relationships, 1993.

The last piece of the above is particularly interesting, because it goes back to the theme of the questions raised above, i.e. about the legitimacy of pooling the so-called “Mechtoid” or even “Cro-Magnoid” specimens together into types or typological entities.

Reading on, we are told:

"...Wiercinski (1965) noted an increase in the "African" (Negroid) element in crania recovered from the early dynastic tombs of Abydos as compared to the previous period. His taxonomy, like others, seems to have a narrow conception the of the range of real "African" variability. In general, this restricted view presents all tropical Africans with narrow noses and faces as being related to or descended from an external, ultimately non-African peoples. However, narrow-faced, narrow-nosed populations have long been resident in Saharo-tropical Africa (Gabel 1966; Hiernaux 1975; Rightmire 1975; Schepartz 1987) and their origin need not be sought elsewhere. These traits are also indigenous. The variability in tropical Africa is expectedly naturally high. Given their longstanding presence, narrow noses and faces cannot be deemed "non-African"..." — Keita

Indeed, some of these features mentioned—such as the narrow nasal index, coupled with mild to low prevalence of prognathism and other characteristics generally associated with the stereotypical “Negro”—have undoubtedly influenced folks like Briggs to reckon certain prehistoric Saharan specimens to be part of the so-called “Mediterranean“ typological family, as was the case with what he dubbed as “African Mediterraneans”; right from the horse’s mouth: “**already slightly** Negroid Hamitic cast of the African Mediterraneans”

However, as pointed out in the extract above, such traits have long been resident to African natural environment, and their origins need no extra-African explanation.

As Hiernaux put it, and as Keita noted, morpho metric variability is quite high in sub-Saharan Africa alone:

Jean Hiernaux "The People of Africa" 1975
p.53, 54

"In sub-Saharan Africa, many anthropological characters show a wide range of population means or frequencies. In some of them, the whole world range is covered in the sub-continent. Here live the shortest and the tallest human populations, the one with the highest and the one with the lowest nose, the one with the thickest and the one with the thinnest lips in the world. In this area, the range of the average nose widths covers 92 per cent of the world range: only a narrow range of extremely low means are absent from the African record. Means for head diameters cover about 80 per cent of the world range; 60 per cent is the corresponding value for a variable once cherished by physical anthropologists, the cephalic index, or ratio of the head width to head length expressed as a percentage....." 

p.135-136

"A quick glance at Figures 4a and 4b will show that the relatively shortest noses occurs only in the tropics, and observation confirms the fact that the nasal bridges of the peoples in question are low as well as being short. At first it seems as though no consistent sense could be made from such an observation since such people as the inhabitants of East Africa right on the equator have appreciably longer, narrower, and higher noses than people in the Congo at the same latitude. A former generation of anthropologists used to explain this paradox by invoking an invasion by an itinerant "white" population from the Mediterranean area, although this solution raised more problems than it solved since the East Africans in question include some of the blackest people in the world with characteristically wooly hair and a body build unique among the world's populations for its extreme linearity and height."

More from Hiernaux:

"Now as mentioned in Chapter 3, the fossil record tells of tall people with long and narrow heads, faces and noses who lived a few thousand years BC in East Africa at such places as Gamble's Cave in the Kenya Rift Valley and at Olduvai in northern Tanzania. "There is every reason to believe that they are ancestral to the living 'Elongated East Africans'. Their features can be found in several living populations, who are very dark skinned and differ greatly from Europeans in anumber of body proportions. Neither of these populations, fossil and modern, should be considered to be closely related to Caucasoids of Europe and western Asia.."
(Hiernaux 1975:62)

The “characterizations” of the “African Mediterraneans” and their “partial derivative” Mechta-Afalou suggest that they could well attain a relative “intermediary” position between northern Eurasians and tropical Africans in a plot of averages of cranio-morphometric centriods. Centroid plots can hide the precise nature of variability within a sample, and so, to that extent, these “African Mediterranean” and “Mechta-Afalou” specimens may assume ‘intermediary’ position, as did the following in Keita‘s centroid plot, although the precise nature of variability respective to the former and Keita’s samples may well be discernable vis-à-vis one another…

“The variability in the population in Upper Egypt increased, as its isolation decreased, with increasing social complexity of southern Egypt from the predynastic through dynastic periods (Keita 1992). The Upper Egyptian population apparently began to converge skeletally on Lower Egyptian patterns through the dynastic epoch; whether this is primarily due to gene flow or other factors has yet to be finally determined. The Lower Egyptian pattern is intermediate to that of the various northern Europeans and West African and Khoisan." — Keita.

To be able to determine whether “Mechtoids” or “Cra-Magnoids” represent a type, one has to examine elaborate cranio-morphometric comparative analysis between the specimens contained in these groupings, and Collin groves work gives us opportunity to do this to some extent:

From Collin Groves, whose reactionary approach to bio-anthropology is all too apparent, the following was presented in his paper of “The terminal Pleistocene and early Holocene populations of northern Africa”, 1999:

To the southeast, further cranially robust remains have been described from Nubia, on the Egyptian-Sudanese border (Anderson 1968; Wendorf 1968a, b; Carlson and Van Gerven 1977). Exactly the same process of gracilisation seems to have taken place in this region; Carlson and Van Gerven (1977) attributed it to a change in masticatory function, associated with the processes leading to the adoption of agriculture. The largest collection, from Tushka and Sahaba, was described by Anderson (1968); he considered them in the context of “Negroid origins”, but ended by concluding that they are strongly resemble the “Maghrebian Cromagnoids”, as he called Mechta-Afalou populations, but considered that they were “half-way to ‘Negroidization’”, and demonstrated the late derivation of sub-Saharans from Caucasoids.

There are therefore a number of hypotheses about these terminal Pleistocene samples, which we propose to test this paper:

—1. That the Mechta-Afalou populations are a generalized “robust” Homo sapiens population (Lahr 1994), or alternatively that they are robust because they are “Cromagnoid” in morphology, i.e. resemble the Upper Paleolithic populations of Europe (Ferembach 1985, Brauer and Rimback 1990)

Groves' results, with regards to ‘robusticity’:

Lahr’s (1994) hypothesis, that the Maghrebian samples resemble the Cro-Magnons, is true as far as the males are concerned, but not for the females. Cro-Magnon females are robust, as are Co-magnon males; Taforalt females, however, are not so robust.

As far as morphology is concerned, Groves' approach to discriminant analysis yields:

The discriminant analysis shows that the Nubian scatter is so wide that it is some of the Nubian males, rather than any of the Maghrebian ones, the are Cromagnon males’ nearest neighbors. The nearest neighbour of the Cromagnon females, however, is the sole Afalou female.

The frequency if occurrence of the horizontal-oval form of the mandibular foramen compares more closely to the Cro-Magnons in the Nubian than in the Maghrebian sample. In the Maghreb sample, it occurs in 1/15, ie. 6.7%, but in the Nubians in 4/18, that is 22.2% (in the Sahaba sample by itself, 4/14, or 28.6%).

According to Frayer (1992), in 38 late upper Paleolithic specimens (approximately contemporary with the present samples) this form occurs in 5.3%, although in 9 Early Upper Paleolithic specimens it was seen in 44.4%.

Present author's take: The specimens previously placed under the ‘Mechta-Afalou’ actually don’t represent a “type”, but an assortment of specimens that share affinities in some respects, and not so much so in others. Even “robusticity’, which it seems has been seized by some to justify classification into a “type” or “categorization”, varies.

—2. That Afalou is slightly less robust than Taforalt (Chamla 1978).

Groves’ conclusion:

Afalou and Taforalt males are very close in all analyses, neither being more robust than the other; the (much smaller) female samples are not so close, indeed the Afalou female is more towards the robust end of the diagrams than are those from Taforalt. We conclude that, though they are much alike, the two samples should preferably be taken separately in future analysis.

—3. That the Nubian sample represents a “Europoid” population undergoing “Negroidization” (Thoma 1973). or… that the Nubian samples belong to the Mechta-Afalou type and are not connected with “Negroid” (sub-Saharan) peoples (Anderson 1968).

Groves says:

This hypothesis cannot be supported. In all analyses, Nubia is well separated from Taforalt, with the Afalou somewhat intermediate. The differences are: longer, narrower calvaria; more development of parietal keel; less rugged occipital and basicranial regions; more prognathous; flatter nasal skeleton; less protruding mandibular syphilis; lower frequency of sharp infer lateral orbital margin; narrower biorbital, wider bizygomaxillary breadth; relatively wider intertribal breadth; lower basibregmatic height in males; less sexual dimorphism; males less robust, females more so. These features recall the differences of modern sub-Saharan (Negroid) populations from those of general Caucasoid type.

Groves concludes with (The present author will relay his perspective in between Groves' comments):

Today the North African and Sub-Saharan gene pools are separated by the Sahara arid zone.

Present author's take: The Sahara never formed a barrier between North Africans and Saharo-tropical Africans. Even his own analysis of select upper Paleolithic African specimens and ‘select’ Howells’ collection of “contemporary” African specimens, is testament to this.

Moving along, with Groves, he continues…

a wide sparsely populated region whose people are intermediate morphologically between “Caucasoid” and “Negroid”. While the late and terminal Pleistocene populations of northern Africa were noticeably more robust than their present-day descendants (as were those of Europe), like them they were differentiated into more northerly “Caucasoid” and more southerly “Negroid” morphologies.  **Yet the transition between these two geographic forms was much further north in the terminal Pleistocene than today**; the terminal Pleistocene Nubians and the Asselar skull are as “Negroid” as are the modern Teita of Kenya; the intermediates were the people of Afalou-bou-Rhummel in Algeria.

Present author's take: This is quite telling, the idea that the so-called transition from “Negroid” to “Caucasoid” characteristics in African populations was much “further north” in the late Pleistocene, than is supposedly the case today. Yet, Groves does not indicate where this break in the said characteristics lie in that transitional belt.

Also, it is worth noting Groves’ mention of ‘robusticity’ in association with “descendants”. Here, the implication is that the reduction in robusticity is an evolutionary product, perhaps as a response to social behavior. Interestingly though, Groves’ says this about “Nubian” groups:

“The conclusion that the Caucasoid/Negroid transition zone was farther north at the end of the Pleistocene, and has shifted south since, then , converges on that of Turner and Markowitz (1990), who reached their conclusion on the basis of **dental characters**. Compared to the Sahaba and Tushka people, Meroitic to near-modern Nubians have a much lower frequency of incisor shoveling, enamel extension, 3-rooted lower first molars and 5-cusped lower second molars, and higher frequency of rocker jaw; all these traits approach later Nubians to Europeans, and the early Nubians to present-day sub-Saharans (Turner and Markowitz 1990).

Some of these differences are quite substantial, and the authors argue strongly that only gene-flow from the north could have accomplished it; in situ evolution could not have done so."

Present author's take: It would seem that Groves doesn’t contest the notion of gene flow, using dental morphology as an indicator, yet the more significant changes in morphology between those of the so-called Upper Paleolithic Europeans (Cro-Magnons in particular) and those of later European groups is supposed to be the product of in situ evolution , and the use of the term “descendants” implying continuity. We all know where Keita stood on this issue:

"Recently Irish (Joel D.) and Turner (1990) and Turner and Markowitz (1990) have suggested that the populations of Nubia and Egypt of the agricultural periods were not primarily descendents of the geographical populations of mesolithic/epipaleolithic times. Based on dental morphology, they postulate as almost total replacement of the native /African epipaleolithic and neolithic groups by populations or peoples from further north (Europe or the near east?)

They take issue with the well-known post-pleistocene/hunting dental reduction and simplification hypothesis which postulate in situ microevolution driven by dietary change, with minimal gene flow (admixture).

However, as is well known and accepted, rapid evolution can occur. Also, rapid change in northeast Africa might be specifically anticipated because of the possibilities for punctuated microevolution (secondary to severe micro-selection and drift) in the early Holocene sahara, because of the isolated communities and cyclicial climatic changes there, and their possible subsequent human effects.

The earliest southern predynastic culture, Badari, owes key elements to post-dessication Saharan and also perhaps "Nubian" immigration. Biologically these people were essentially the SAME. It is also possible that the dental traits could have been introduced from an external source, and increased in frequency primarily because of natural selection, either for the trait or for growth pattern requiring less energy.

There is no evidence for sudden or gradual mass migration of Europeans or Near Easterners into the valley, as the term 'replacement' would imply.

There is limb ratio and craniofacial morphological and metric CONTINUITY in Upper-Egypt-Nubia in a broad sense from the late paleolithic through dynastic periods, although change occured." — Keita, Studies and Comments on Ancient Egyptian Biological Relationships.

And as presented earlier, with respect to dental analysis as an isolated tool to draw conclusion:

"As previously mentioned, a review of the photographs and descriptions of Nazlet Khater (30,000 BP), Wadi Kubanniya (20,000 BP), Jebel Sahaba-Wadi Halfa (12,000-6000 BP) and Badari-Nakada-Dynasty I (4400BC-3100 BCE) remains suggest CONTINUITY (Thomas 1984; Stewart 1985; Angel and Kelly 1986; Anderson 1968; Strouhal 1971; Morant 1925). Thomson and MacIver (1905) found continuity throughout the dynastic period. This is not to suggest that no Near Eastern immigration occurred, but it is to caution against the sole use of one kind of data when postulating mass human movements. All kinds of data must be used to choose between competing models of explanation.” — Keita.

Back to Groves:

…These climatic fluctuations surely bear on the genetic question. The climate of Nubia in the Qadan period was less arid than today, corresponding to one of Butzer’s short high-water substages of the Nile, and the fundamentally sub-Saharan affinities of the Sahaba/Tushka people may thus result from the northward extension of Afro-tropical sub-arid vegetation belts. Aridity in the Sahara, however, still held sway; comparatively little gene-flow penetrated it, leaving the contemporary Maghrebian population (Taforalt) fully “Cro-Magnon” in type. The early Holocene climatic amelioration, with its northward spread well north, such that now Maghrebians became of distinctly intermediate type (Afalou), and even as late as 6,000 BP fully “Negroid” people still occupied northern Mali (Asselar). In this scheme, the distribution of “Negroid” peoples, and of the transition zone to their north, fluctuated according to climatic vicissitudes.

And, Keita:

“The supra-Atlas mountains and coastal northern Africans are viewed here as perhaps being more, but not only, related to southern Europeans, primarily by gene flow. Given that Berber languages are not creoles, which, if they were, might indicate massive European contact, it may be well to view the gene flow as having occurred steadily over a long time…”

"Early southern Egyptian/Nubian and Saharan remains are clearly a part of the Saharo-tropical range of variation. Northern modern Berber-speakers are frequently notably "European," in phenotype but even they have tropical African "marker" gene frequencies than those found in southern Europeans. "Blacks" have long lived in northern Africa (see review in Keita 1990)." — Keita.

Brace recently showed how Neolithic and Bronze age Europeans in various European regions less resemble the contemporary counterparts, particularly in the case of northern European regions, and how the so-called Cro-Magnon is quite distinct from contemporary Maghrebian groups [and contemporary European samples for that matter]. I found it interesting that Groves retained the term “Cro-Magnon” [which he seems to associate with "Caucasoids"] in association with Upper Paleolithic/ late Pleistocene north African specimens, instead of replacing it with “Caucasoid”. If anything, Groves own analysis is testament to how problematic his resort to typological terms like “Caucasoid” and “Negroid” are. When taken to perspective, it becomes apparent that the so-called “Mechtoid” groups found in the Upper Nile Valley, are actually remains of folks who had substantial affinity with Saharo-tropical Africans…it doesn’t reflect a type called “Mechta-Afalou”. In fact, the latter isn’t even a type, and we’ve just seen that. Mechta-Afalou, should therefore be dropped, and not forwarded as though it represents a well defined and disparate entity!

To be continued!

Link to part 2:  http://exploring-africa.blogspot.com/2008/02/mechta-afalou-and-so-called-mechtoids.html

Cruciani et al. 2007: Sorting Out a Complex Network of Clusters

E-M78 (E3b1) network:

Introduction
Both E3a and E3b are found outside of their African homeland, but '''E3b''' is relatively more frequent in Europe and western Asia than its sister clade E3a, thanks to gene flow from North Africa and to a lesser degree, from the African Horn in sub-Saharan East Africa [to the other side of the Red Sea], where E3b bearing chromosomes appear to be the most prevalent. The most commonly distributed E3b sub-branch is '''E-M78'''. The flow of E3b can be summarized into about four main episodes, based on geographic and quantitative analysis of haplogroup and micro satellite diversity:

• Sometime in the Upper Paleolithic, between 23.9 and 17.3ky ago, E3b (M215) bearing chromosomes were introduced to northeast Africa from sub-Saharan East Africa.
  

• The M78 mutation ('''E3b1''') then occurred in the E3b chromosomes distributed in Northeast Africa, to be followed by a back-migration episode to sub-Saharan East Africa, sometime between 18ky and 5.9ky ago. Some chromosomes which had acquired the M78 mutation in Northeast Africa undoubtedly also made their way westward in North Africa.
  

• Sometime around 13ky ago, these M78 bearing E3b chromosomes were introduced to Europe directly from northern Africa.

• Between 20 and 6.8ky ago, M78 bearing E3b chromosomes were introduced into western Asia from Northeast Africa. [Cruciani et al. 2007]
  

Discussion
Sorting E-M78 chromosomes into well defined clusters, while there are certainly strong correspondances between binary markers and microsatellite clusters in certain cases, is anything but simplistic.

What Cruciani did in his efforts to place microsatellite clusters into clearly defined sub-clades more precisely, and identification of new sub-clades in the process, was to muddle up what is presently known about E-M78 macrohaplogroup demographic and biohistoric specificities, and he, himself, has taken note of this fact:

Thus, even though they represent only 5% of the total E-M78 chromosomes analyzed, their inclusion into the respective haplogroups/paragroups **heavily affects inferences** about time and place of origin of these haplogroups/paragroups. — Cruciani et al., 2006.

...taken from the following extract:

Discrepancies between micro satellite clusters and haplogroups/paragroups

Despite the major congruence between E-M78 microsatellite clusters and binary haplogroups, there are important discrepancies between the trees generated by the two types of markers. First, the large majority of the delta chromosomes belong to the clades E-V22 and E-V12*, but a few representatives of both clades are found outside the delta cluster.

Within delta, E-V22 and E-V12* chromosomes are intermingled and not clearly differentiated by their microsatellite haplotypes.

Second, all of the cluster beta chromosomes belong to paragroup E-M78*. However, E-M78* also includes some non-beta chromosomes which are highly differentiated in their microsatellite haplotypes.

Third, there is a striking correspondence between the microsatellite clusters alpha and gamma and the binary haplogroups E-V13 and E-V32, respectively (Fig. IB). However, while all alpha cluster belong to E-V13, some E-V13 chromosomes are not contained in such a cluster. Conversely, all of the E-V32 chromosomes fall within cluster gamma (defined by the rare DYS19 11-repeat allele), but two gamma chromosomes are members of paragroups E-V12* and E-M78*.

Taking into account the above data, the previously described European cluster alpha and the northern African cluster beta are indeed confirmed as monophyletic groups of chromosomes, that, very likely, have their own binary markers yet to be discovered. Cluster alpha chromosomes constitute a major branch of the binary haplogroup V13, which, in turn, includes also a few, highly differentiated chromosomes - previously classified either in cluster delta or unclassified. All 29 chromosomes within cluster beta belong to the paragroup E-M78*, which is relatively rare and almost exclusively restricted to a single geographic region (i.e. northern Africa), thus a common origin for at least a large part of these is likely.

Different scenarios characterize clusters delta and gamma.

The presence of three E-V13 chromosomes within cluster delta and the exclusion of some E-V12 and E-V22 chromosomes demonstrate that cluster delta cannot be regarded as a monophyletic unit.

As for cluster gamma, we have established close phylogenetic relationships of its members - now classified as E-V32 chromosomes - with those belonging to E-V12* within the E-V12 clade (Fig. 2) These relationships go undetected through the micro satellite network (red and pink chromosomes in Fig. 1B), most likely due to recurrent mutations at micro satellite loci. An alternative explanation would be that V12 is within a terminal branch of the Y chromosomes tree; moreover, it was never found by sequencing 18 Y*(xM78) chromosomes representing deep branches of the Y chromosome phylogeny (data not shown). Thus, the new markers we have detected now offer the opportunity to explore in a better defined phylogenetic context the origin and distribution of the chromosomes belonging to haplogroup E-M78.

Also it is worth noting that twelve chromosomes that we were unable to assign to any cluster in the previous network analysis are now classified within four different haplogroups/paragroups (see Table 2 and Fig. 1B) as highly divergent microsatellite haplotypes. Thus, even though they represent only 5% of the total E-M78 chromosomes analyzed, their inclusion into the respective haplogroups/paragroups **heavily affects inferences** about time and place of origin of these haplogroups/paragroups.

Finally, although there is a strong correspondence between cluster gamma - defined by the rare DYS19 11-repeat allele - and haplogroup E-V32, the presence, in cluster gamma, of haplotypes belonging to the binary paragroups E-M78* and E-V12* can only be explained by admitting either a paraphyletic or a polyphyletic origin for the chromosomes in the cluster.

Overall these findings indicate that caution is needed when using the microsatellite alleles as surrogates of UEPs (e.g. Malaspina et al., 2001; Cruciani et al., 2004’ Di Giacomo et al., 2004; Sanchez et al.; 2005). — Cruciani et al., 2006; Molecular Disection of the Y chromosome Haplogroup E-M78 (E3b1a): A Posterior Evaluation of a Microsatellite-Network-Based Approach Through Six New Biallelic Markers

He correctly notes [in the very last piece of this extract] the futility of treating clusters as lineages, for reasons made apparent already in the body of the extract.

Essentially, as noted above, all the 29 beta clusters fall into the E-M78* paragroup found predominantly in Northwest Africa, along with a few other clusters [gamma and unclassified clusters]. In his 2007 study, however, Cruciani had this to say:

It is also worth noting that the rare paragroup E-M78* has not been observed in eastern Africa; moreover, the two north-western African E-M78* chromosomes are well differentiated from the two north-eastern African E-M78* chromosomes (supplementary table 1) adding a new argument for a higher haplogroup diversity in northern Africa. — Cruciani et al., Tracing Past Human Male Movements in Northern/Eastern Africa and Western Eurasia: New Clues from Y-chromosomal Haplogroups E-M78 and J-M12, 2007.

Thus, the paragroup essentially consists of clusters sharing TMRCA, but didn't test positive for any known downstream mutations. So, the likely differences seen here by Cruciani, were of microsatellite cluster differences. It can happen, and has happened as noted above, when newly identified binary markers are stumbled upon in paragroups. The general assumption is that, in whichever population there is the highest concentration of the paraphyletic group of a clade, generally taken into consideration with considerable frequency and diversity, the high probability is that this is the 'representative' group wherein the clade was initially acquired and then spread out, and transmitted through the generations. Clades differentiated by microsatellite clusters in a paraphyletic group, could therefore be seen in the context of having undergone differentiation at the microsatellite level, but likely before downstream potential UEP mutations were acquired in the respective clusters [i.e. polyphlyetic clusters], that is—if we rule out independent parallel microsatellite mutations in the case at hand. So, generally speaking, a paraphyletic cluster of a clade with, i.e. no known downstream mutations of its sub-clades, are viewed as ancestral markers—no news here.

Another exemplary case, would be that of V12* paragroup, wherein clusters have yet to be differentiated into clearly identified V12 sub-clades:

Taking into account the above data, the previously described European cluster alpha and the northern African cluster beta are indeed confirmed as monophyletic groups of chromosomes, that, very likely, have their own binary markers yet to be discovered. — Cruciani et al. 2006.

So, why?, because as noted in the extract, for example...

there is a striking correspondence between the microsatellite clusters alpha and gamma and the binary haplogroups E-V13 and E-V32, respectively (Fig. IB). However, while all alpha cluster belong to E-V13, some E-V13 chromosomes are not contained in such a cluster. Conversely, all of the E-V32 chromosomes fall within cluster gamma (defined by the rare DYS19 11-repeat allele), but two gamma chromosomes are members of paragroups E-V12* and E-M78*. — Cruciani et al.,2006

This strong correspondence between certain clusters and binary markers, but NOT total correspondence, goes back to the point made about the polyphyletic clusters that Cruciani alluded to and that the present author briefly illustrated in a scenario above, concerning the paragroup.

Wherever V12 may have arisen [in Africa], it seems to be the ancestral lineage to E-V32, which has almost all of the gamma clusters identified and is found mainly in east Africa, particularly in the African Horn.

Earlier, the present author wrote:

"Clades differentiated by microsatellite clusters in a paraphyletic group, could therefore be seen in the context of having undergone differentiation at the microsatellite level, but likely before downstream potential UEP mutations were acquired in the respective clusters [i.e. polyphlyetic clusters], that is - if we rule out independent parallel microsatellite mutations in the case at hand. So, generally speaking, a paraphyletic cluster of a clade with, i.e. no known downstream mutations of its sub-clades, are viewed as ancestral markers—no news here."

And so, when looking at this...

there is a striking correspondence between the microsatellite clusters alpha and gamma and the binary haplogroups E-V13 and E-V32, respectively (Fig. IB). However, while all alpha cluster belong to E-V13, some E-V13 chromosomes are not contained in such a cluster. Conversely, all of the E-V32 chromosomes fall within cluster gamma (defined by the rare DYS19 11-repeat allele), but two gamma chromosomes are members of paragroups E-V12* and E-M78*. — Cruciani et al.,2006

...since, it appears that the clusters above are both monophyetic group of chromosomes, it would appear that the V13 was a potentially unique mutational single-event that occurred prior to the mutational events [in tandem repeat nucleotide sequences] characterizing the microsatellite cluster 'alpha', so that it would appear in association with two different microsatellite clusters. Essentially, V13 assumes the role similar to that characterized by the "clade" which identifies the paraphyletic group in the above mentioned scenario. Conversely, it would appear that cluster gamma came to being sometime after the M78 mutation, but before V12 mutation. This would likely explain why an M78 chromosome, which appears to be devoid of any known downstream M78 mutations, would have this microsatellite cluster as do V12* and its derivative V32. The V12 chromosomes that have the delta cluster, may well be the product of multiple mutational events—that is, convergent "parallel mutations". See:

The presence of three E-V13 chromosomes within cluster delta and the exclusion of some E-V12 and E-V22 chromosomes demonstrate that cluster delta cannot be regarded as a monophyletic unit

Now of course, in the event that the present author may have overlooked something here or there, the information herein is subject to modification.

NRY Haplogroup E3a: A Multidisciplinary Proposal of Its Origins

Having touched on this matter in an earlier posting but in a broader topic involving more lineages, this post will focus on one lineage—haplogroup E3a.

Geological and geographical evidence

~23 ky ago: Ogolian aridity takes hold, and renders much of north Africa desertified.

The advent of Hg E3a's TMRCA essentially coincides with rise of the Ogolian aridity.

• PN2 clade (E3) bearers in the vicinity of the general expanse straddling Sudanese-Central African Republic -Ugandan-Kenyan region [get a map aid, if necessary] give rise to E3a ~ between 21 and 18 ky ago [see Semino et al. 2004 for TMRCA dates, pending additional or new info]; E3b-M35* would have likely arose relatively earlier than E3a* [as evidenced by its near absence in some the populations that carry this], sometime prior to the Ogolian and the LGM period.

Hence, indications are that the initial territory of an ancestral Hg E3a bearing group would have likely started south of the Sahara, at a time when:

• The Ogolian aridity rendered much of North Africa with adverse weather conditions, turning much of that general region into desert. The Sahara at this time, extends south beyond its current boundaries to a certain point, likely as far as a little beyond the Niger bend.

• The above mentioned geological conditions in the aforementioned geography indicate that the population density in those arid regions would have been quite sparse—meaning, that most populations would have then been concentrated south of the broad desert region.

Reference to the geographical extent of this desertification is laid out here in maps: AFRICA DURING THE LAST 150,000 YEARS [clickable]

Archaeological evidence
Archaeology indicates that much of west Africa during the height of the Ogolian aridity was abandoned, with many of the populations living therein in the pre-Ogolian periods seeking refuge in the last vestiges of vegetation beyond the desert, which at the time - as noted above, extended to as far as beyond the Niger River bend, and possibly few moving to the far northwestern coast of Africa, if not crossing over to the Iberian or Southwestern European region [perhaps to this end, possible case can made from findings in Goncalves et al. 2005?], which was then a major refuge center for European groups trying to cope with the side-effects of the LGM in their neck of the woods. Vivid archaeological indicator of this comes from:

• "After a favourable climatic period, characterised by relatively dense and diversified Palaeolithic occupations, the arid Ogolian begins locally around 23000 years BP and is represented at Ounjougou by a significant depositional and archaeological hiatus." — Aziz Ballouche [see: Link ]

Incidentally, when this was going on in west Africa, arid conditions extended all the way to the horn-shaped coast of the African Horn, possibly encouraging populations to reside relatively more inwards—that is, away from that aridified horn-shaped coastal region; rather, populations of that region were likely encouraged to seek refuge in the general region straddling southern Sudan, Ethiopia, Kenya and Uganda or even further—i.e. region straddling Uganda, Kenya, and Tanzania. [See AFRICA DURING THE LAST 150,000 YEARS, for visual aid—geology conditions via geography in the Ogolian period]

It is again, from archaeological evidence, that we get a picture of when repopulation events make their appearance, and in what pattern they occur, i.e. things which are all relevant to understanding the circumstances and nature of how the Hg E3a bearing group makes it appearance in west Africa:

• Consequently, it has to be seen in the context of heavy rainfalls and a resettlement of the vegetation cover, during the 10th millennium BC, that a **new population** arrives on the Plateau of Bandiagara." — Human population and paleoenvironment in West Africa [see: Link ]

...and we see how these repopulation events occur sequentially from archaeological record, showing a movement from an east-to-westward direction, and thereafter a south-to-northward movement in west Africa itself:

• From 30,600 to 10,000 BC: "A cultural flow, from the southeast of Subsaharan Africa and to the Sahara, could explain the diffusion of the microlithic industries all the way through West Africa. We observe them initially in Cameroon at Shum Laka (30.600-29.000 BC), then at the Ivory Coast in Bingerville (14.100-13.400 BC), in Nigeria in Iwo Eleru (11.460-11.050 BC), and finally in Ounjougou (phase 1, 10th millennium BC)." — Human population and paleoenvironment in West Africa [see: Link ]

This east-to-west movement shows that a new group of people moved into west Africa, because the "microlithic traditions" that appear at Shum Laka had been in existence for as long as ~ 30 ky ago, and yet didn't show up in west Africa proper until ~ 14 ky ago, a late date which works well within the confines of the TMRCA age of Hg E3a. So the people originally responsible for that "microlithic tradition" at Shum Laka were not the people who likely brought that tradition to west Africa, but by a new group of people who passed through Shum Laka. These new group of people first appeared in vegetation holdout regions beyond the Niger bend, and gradually moved northward, eventually reaching to regions as far as that of Ounjougou, as evidenced by the above carbon-dated archaeological finds. It should be remembered that the Ounjougou region was abandoned in the intense desertification period.

*Details of the "microlithic traditions" had been provided in a related earlier post: P2 Clades: The Arrival of E3a and E3b Haplogroups [clickable]

Genetic evidence
The east-to-west movement of new groups [the candidates being E3a bearing group] into west Africa observed above, seems to be lent further support from genealogical finds.

Observations of genetic differentiation within contemporary E3a bearing populations, suggests that the earliest Hg E3a bearing groups, carrying mainly M2, P1 and M180 mutations devoid of the M191 mutation, had moved to the far west region of Africa...from an eastern-oriented origin:

Consider for one,

• Although haplotypes 22, 24, and 41 were probably all involved in the Bantu expansion, the processes that determined the current distribution of these haplotypes in the Sudanese belt (a region south of the Sahara extending from western to central Africa) seem to have been more complex and perhaps involved a separate expansion.

• In particular, haplotype 24 and its derivative, haplotype 22, harbor opposite clinal distributions in the region, a finding that is at odds with the hypothesis of a parallel dispersion of these two lineages in the area.

• Haplotype 22 has a frequency of 23% in Cameroon (where it represents 42% of haplotypes carrying the DYS271 mutation), 13% in Burkina Faso (16% of haplotypes carrying the DYS271 mutation) and only 1% in Senegal (Semino et al. 2002), whereas haplotype 24 reaches its highest frequency (81%) in Senegal (Semino et al. 2002).

• A possible explanation might be that haplotype 24 chromosomes were already present across the Sudanese belt when the M191 mutation, which defines haplotype 22, arose in central western Africa. Only then would a later demic expansion have brought haplotype 22 chromosomes from central western to western Africa, giving rise to the opposite clinal distributions of haplotypes 22 and 24.

Source: Cruciani et al. 2002, A Back Migration from Asia to Sub-Saharan Africa

This piece shows that the oldest Hg E3a bearing populations, characterized by high frequencies of haplotype 24 and relatively modest frequencies of haplotype 22, remain localized in West Africa; the contrasting distribution and frequency patterns of these haplotypes suggest that the higher the population with haplotype 22, the less older it is in its genetic composition relative to those bearing less haplotype 22 in a gene pool dominated by the relatively older haplotypes, like haplotype 24. Senegal appears to have the highest concentration of haplotype 24, and interestingly, the lowest concentration of haplotype 22...thus, making it likely the oldest Hg E3a bearing group.

The Senegalese samples also have other peculiarities that further support the aforementioned idea of their being the oldest Hg E3a bearing group:

• Hg E3 (P2 or PN2 clade):
  
  Bantu (South Africa) - E3* = 1.9%, Senegalese - E3* = 2.9%, Ethiopian (Amhara) - E3* = 10.4%, Ethiopian (Oromo) - E3* = 12.8% in the ascending order.
  

...the 'older' groups appear to have relatively wider distribution of E3, as the Senegalese sample in particular seems to indicate vis-a-vis other Niger-Congo speaking groups elsewhere; a lineage which has by far the highest frequencies and distribution in Ethiopia [which is in East Africa fyi]

The Senegalese sample shows considerably more E-M35* than that from other Niger-Congo speaking groups of sub-Saharan West Africa, which are not immediately neighbouring major "ancient" African groups in East Africa or like Khoisans.

Hg E-M35* lineages:

• In descending order…Ethiopian (Oromo) - E-M35* = 19.2%, KhoiSan (South Africa) - E-M35* = 16.7%, Ethiopian (Amhara) - E-M35* = 10.4%, Berber (North-Central Morocco) - E-M35* = 7.9%, Berber (Southern Morocco) - E-M35* = 7.5%, Senegalese - E-M35* = 5%, Tunisian - E-M35* = 3.4%, Algerian - E-M35* = 3.1%, Arab (Morocco) - E-M35* = 2.3% , Burkina Faso -E-M35* = .9%
  

The Senegalese group is also the only sub-Saharan 'predominantly-Niger-Congo' speaking group that shares the rare microsatellite motif with Ethiopians on the E-M78 bearing chromosome:

It is interesting that both E-P2* and E-M35* and their derivatives, E-M78 and E-M123, exhibit in Ethiopians the 12-repeat allele at the DYS392 microsatellite locus, an allele scarcely seen (Y-Chromosome STR Database), especially in other haplogroups and other populations (A.S.S.-B., unpublished data).

In addition, the Ethiopian DYS392-12 allele is usually associated with the unusually short DYS19-11 allele, which is typical of this area. These findings are not easily explained. One possible scenario is that an ancient differentiation of the E-P2 haplogroup occurred in loco (East Africa). However, this also implies a low mutability of the associated microsatellite motif (DYS392-12/DYS19-11). Alternatively, the microsatellite motif may be due to homoplasy.The first scenario is more likely, since this unique microsatellite haplotype occurs in E-P2*, E-M35*, and E-M78 but is almost *absent in all other haplogroups and populations*.

In addition, the high stability of the DYS392 locus (Brinkmann et al. 1998; Nebel et al. 2001) and of the shorter alleles of DYS19 (Carvalho-Silva et al. 1999) has been reported elsewhere.

Moreover, the observation that the derivative E-M78 displays the DYS392-12/DYS19-11 haplotype suggests that it also arose in East Africa. This is illustrated by the microsatellite network (fig. 3, shaded area), which reveals that the Ethiopian branch harboring DYS392-12 is not shared with either Near Eastern or European populations. — Semino et al. Origin, Diffusion, and Differentiation of Y‐Chromosome Haplogroups E and J, 2004.

The Ethiopian sample may not share the said allele with those populations mentioned, including the northwest African samples as far as the present author can tell, but it does share the said allele with the Senegalese sample [see fig. below], which would suggest that the Senegalese M78 derivative didn’t come from interaction with its northwest African neighbors; rather, they may well be relics of ancient migrations from east to west.

For larger image, click on this link: Source

So what do all these genetic indicators say?

Senegalese sample has the highest concentration of haplotype 24 and the lowest concentration of haplotype 22 - making it the most likely ancient Hg E3a bearing group, it also has higher Hg E3 vis-a-vis other Niger-Congo speaking group of west Africa, has the higher Hg E-M35* vis-a-vis other Niger-Congo speaking groups not neighbouring major "ancient" populations of east Africa or south Africa [aka KhoiSans], and has the rare Ethiopian/East African 12-repeat allele at the DYS392 locus.

The advent of Hg E3a itself coincides with the rise of the Ogolian aridity, which rendered much of North Africa to as far as beyond the Niger River bend largely inhabitable, inducing populations to be densely populated south of the Sahara, which is therefore the likely region of the rise of TMRCA of Hg E3a bearers.

Bearing "rare" lineages predominantly found in east Africa - i.e. the likely point of origin, along with sequential archaeological evidence for [east-to-west and thereafter, in situ west African south-to-north] repopulation events in west Africa, much of which was abandoned in the Ogolian desertification, show that the earliest Hg E3a bearers— which finds expression in Senegalese samples - could not have arose in situ west Africa, but originated in an eastward oriented geography and migrated to west Africa, as the Ogolian aridity relaxed, bringing along with them new microlithic traditions picked up from the Shum Laka region, settled therein and thereafter underwent demic expansion, resulting in the "high diversity and frequency" of the Hg E3a distribution in west Africa.

All this becomes even more apparent, when one realizes that Hg E3 (PN2 clade) is quite rare even in sub-Saharan west Africa, but even rarer in the Sahara. It has the highest frequency in sub-Saharan east Africa [Ethiopia], where it is deemed to have originated— and so, the likelihood of the emergence of Hg E3a in a region with significantly higher frequencies of Hg E3 makes more sense than vice versa.

The above are all the reason the present author found it particularly simplistic in a discussion that he was a part of in the past, a strange question asked by a discussant, as to how one could possibly reconcile 'high diversity and frequency' of Hg E3a in west Africa with the prospect of its origins outside of west Africa; that question was no doubt a mentality born out of lack of familiarity with genetics and how multidisciplinary science works.

Update!

Getting back to the point raised earlier about the rare 12-repeat allele at DYS392 by Semino et al...

It is interesting that both E-P2* and E-M35* and their derivatives, E-M78 and E-M123, exhibit in Ethiopians the 12-repeat allele at the DYS392 microsatellite locus, an allele scarcely seen (Y-Chromosome STR Database), especially in other haplogroups and other populations (A.S.S.-B., unpublished data). 

In addition, the Ethiopian DYS392-12 allele is usually associated with the unusually short DYS19-11 allele, which is typical of this area. These findings are not easily explained. One possible scenario is that an ancient differentiation of the E-P2 haplogroup occurred in loco (East Africa). However, this also implies a low mutability of the associated microsatellite motif (DYS392-12/DYS19-11). Alternatively, the microsatellite motif may be due to homoplasy.The first scenario is more likely, since this unique microsatellite haplotype occurs in E-P2*, E-M35*, and E-M78 but is almost *absent in all other haplogroups and populations*.

In addition, the high stability of the DYS392 locus (Brinkmann et al. 1998; Nebel et al. 2001) and of the shorter alleles of DYS19 (Carvalho-Silva et al. 1999) has been reported elsewhere.
Moreover, the observation that the derivative E-M78 displays the DYS392-12/DYS19-11 haplotype suggests that it also arose in East Africa. This is illustrated by the microsatellite network (fig. 3, shaded area), which reveals that the Ethiopian branch harboring DYS392-12 is not shared with either Near Eastern or European populations. — Semino et al. Origin, Diffusion, and Differentiation of Y‐Chromosome Haplogroups E and J, 2004.

To which the present author responded...

The Ethiopian sample may not share the said allele with those populations mentioned, including the northwest African samples as far as I can tell, but it does share the said allele with the Senegalese sample [see fig. below], which would suggest that the Senegalese M78 derivative didn’t come from interaction with its northwest African neighbors; rather, they may well be relics of ancient migrations from east to west.

Cruciani et al. in their 2007 publication, Tracing human male movements in northern/eastern Africa and western Eurasia: new clues from Y-chromosomal haplogroups E-M78 and J-M12, had this to say about the 12-repeat allele in question:

“An eastern African origin for this haplogroup was hypothesized on the basis of the basis of the exclusive presence in that area of a putative ancestral 12-repeat at the DYS392 micro satellite , found in association with E-M78 chromosomes (Semino et al. 2004). North-eastern African populations were not represented in that study.

In order to test this hypothesis, we analyzed for DYS392 a geographically widespread subset of the E_M78 chromosomes here identified. We observed that the DYS392 12-repeat allele is associated with the majority of the chromosomes belonging to the north-eastern African E-V12* (15 out of 18) and to the eastern African E-V32 (21 out of 23), with about half (9 out of 21) of the E-V22 chromosomes (both in eastern and north-eastern Africa), with a few of the European E-V13 (2 out of 23) and with some north-African E-V65 (3 out of 16) chromosomes.

These findings show that the DYS392 12-repeat allele is common in different regions characterized by high frequencies of E-M78, and suggest that it was most likely generated by multiple mutation events occurring in different UEP-defined sub-haplogroups. Thus, the DYS392 allele distribution is not informative to infer the place of origin of E-M78 chromosomes.”

Cruciani et al. point out that Northeast Africa wasn't represented in the 2004 Semino et al. study, presumably to emphasize the point that its detection therein would have shown that the 12-repeat allele in question wasn't confined to sub-Saharan east Africa, particularly Ethiopia. It is certainly true that northeastern Africa was not represented, but in fact, a close examination of Semino et al.'s 2004 study, shows that the 12-repeat allele wasn't confined to sub-Saharan east Africa; it makes single or very low appearances in the "Near Eastern" and "European" samples, and interestingly none in north African [sans northeast Africa] samples.

Cruciani et al. on the other hand, did detect the 12-repeat allele in north African [sans northeast Africa], but still in relative low frequency (3 out of 16). The same applies to their findings in European samples, where it appears to be yet rarer than that of the north African samples. Considerable frequency is however noted in their northeast African sample, and consistently, in sub-Saharan east African samples. So, even going by Cruciani et al.'s findings, the greater distribution of the 12-repeat allele in eastern Africa in general, would argue for its introduction from eastern Africa.

Cruciani et al. reckon that simply because the 12-repeat allele is not confined to east Africa, it therefore doesn't allow one to infer the place of origin of E-M78 bearing chromosomes. This ignores the point just made about its relatively rare occurrence outside of east Africa. Cruciani et al. reach this conclusion on the understanding that the 12-repeat allele's appearances in distinct sub-clades invokes homoplasy or parallel mutational events, and indeed, Semino et al. 2004 did not rule out that possibility, but unlike Cruciani et al. they took additional material into consideration:

1) "It is interesting that both E-P2* and E-M35* and their derivatives, E-M78 and E-M123, exhibit in Ethiopians the 12-repeat allele at the DYS392 microsatellite locus, an allele scarcely seen..."

So while there is notable presence of 12-repeat allele bearing E-M78 chromosomes in northeast Africa as well, only in sub-Saharan east Africa does one come across not only considerable frequencies of E3-P2 [PN2 clade], but also the more immediate precursor of Hg E-M78, i.e.— Hg E-M35*, which bear this 12-repeat allele. As far as the present author can discern at this point, pending introduction to studies that suggest otherwise, the ensemble of at least three different PN2 macro-clades—including the ancestral ones—bearing the said "12-repeat allele" only occurs in sub-Saharan east Africa. Case in point:

"...first scenario is more likely, since this unique microsatellite haplotype occurs in E-P2*, E-M35*, and E-M78 but is almost *absent in all other haplogroups and populations*."

2) "One possible scenario is that an ancient differentiation of the E-P2 haplogroup occurred in loco (East Africa). However, this also implies a low mutability of the associated microsatellite motif (DYS392-12/DYS19-11)...

In addition, the high stability of the DYS392 locus (Brinkmann et al. 1998; Nebel et al. 2001) and of the shorter alleles of DYS19 (Carvalho-Silva et al. 1999) has been reported elsewhere."

So again, while not ruling out independent parallel microsatellite mutational events across different PN2 clades, the repeat occurrence of the 12-repeat allele across different PN2 clades, including the ancestral ones, coupled with the possibility of "low mutability", which translates into "high stability" of the locus in question, indicates that the 12 repeat could well have also been inherited from a precursor PN2 clade(s). If the latter is the case, certainly sub-Saharan East Africa as the likely place of origin for the allele, can be put forward as a strong argument. And in getting back to the appearance of this allele in sub-Saharan or Sahelian west Africa, in the Senegalese sample for instance, would tend to favor an east African origin at some point in history, rather than as a remnant of interactions with coastal northwest Africans, where the allele is rare, even going by Cruciani et al.'s findings.