Showing posts with label Haplogroup. Show all posts
Showing posts with label Haplogroup. Show all posts

Sunday, June 30, 2013

Haplogroup Assignment; Old Habits that Die Hard

Introduction:


It has become a common theme in DNA research papers dealing with population genetics, particularly those that are either published in the "west" or else rely heavily on references to previous publications by "western" research teams, to dichotomize human phylogeny neatly into two main types: African and non-African. As a result, a good amount of the readership of these papers have also become accustomed to treating human phylogeny accordingly. No doubt that the reactionary segment of that readership have applied such a phylogenetic arrangement synonymously with "races" of humanity.

It's one thing to assign human phylogeny into two main types, but it's another, in terms of how these assignments take form. One would be hard-pressed not to come across a single example, whereby lineage that is given an "L" designation in mictochondrial phylogeny, is automatically treated as "African", while the two main offshoots of the L3 clade are taken for granted as "non-African". Such arrangements tacitly or by design, insinuate non-overlapping phylogeny between the so-named two main groups. The discussion section will deal with this kind of arrangement of human phylogeny further, applying specific examples from published material.

Wednesday, December 9, 2009

R1*-M173 Chromosomes in Africa - II

On another matter of African haplogroup R chromosomes...

As of Dec 4, 2009, the following was released by Molecular Anthropology in the Genomic Era team which oversaw the 4th International conference of the series on DNA polymorphisms in human populations that took place at University La Sapienza - Rome from December 3 through to 5, 2009: 

Fulvio CRUCIANI (Italy)*

Human Y-chromosome haplogroup R1b1a (R-V88): A paternal genetic record of early-mid Holocene trans-Saharan connections

Human Y chromosomes belonging to haplogroup R-P25 are quite rare in Africa, being found mainly in Asia and Europe. However, a group of P25 Y chromosomes that are not defined by the presence of a downstream derived marker (the paragroup R-P25*) are found concentrated in the central-western part of the African continent, where they can be detected at frequencies as high as 95%. Phylogenetic evidence and coalescence time estimates suggest that R-P25* chromosomes (or their phylogenetic ancestor) may have been carried to Africa by an Asia-to-Africa back-migration in prehistoric times. Here we describe six new mutations that define the relationships among the African R-P25* Y chromosomes and between these African chromosomes and previously reported R-P25 Eurasian sub-lineages. The incorporation of these new mutations into a phylogeny of the R-P25 haplogroup led to the identification of a new clade (R1b1a or R-V88) encompassing all the African R-P25*, about half of the few European/west Asian R-P25*, and the R-M18 chromosomes. A world-wide phylogeographic analysis of the R-P25 haplogroup provided strong support to the Asia-to-Africa back-migration hypothesis. The analysis of the distribution of the R-V88 haplogroup in more than 1,800 males from 69 African populations, revealed a striking genetic contiguity between the Chadic-speaking peoples from the central Sahel and several other Afroasiatic speaking groups from North Africa. The R-V88 coalescence time was estimated at 9,200-5,600 kya, in the early-mid Holocene. We suggest that R-V88 is a paternal genetic record of the proposed mid-Holocene migration of proto-Chadic Afroasiatic speakers through the Central Sahara into the Lake Chad Basin.

* With:
Beniamino Trombetta (1), Daniele Sellitto (2), Andrea Massaia (1), Giovanni Destro-Bisol (3), Elizabeth Watson (4) Eliane Beraud Colomb (5), Jean-Michel Dugoujon (6), Pedro Moral (7), Rosaria Scozzari (1)
(1) Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, Rome 00185, Italy; (2) Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome 00185, Italy; (3) Dipartimento di Biologia Animale e dell'Uomo, Sapienza Università di Roma, Rome 00185, Italy; (4) The Swedish Museum of Natural History, Stockholm, Sweden; (5) Laboratoire d'Immunologie, Hôpital the Sainte-Marguerite, Marseille, France; (6) Laboratoire d'Anthropobiologie, FRE 2960, Centre National de la Recherche Scientifique (CNRS) Université Paul Sabatier, Toulouse, France; (7) Departament of Biologia Animal, Universitat de Barcelona, Barcelona, Spain.

Cruciani is known for making observations that don't exactly match up with what his actual DNA results show. The present author pointed this out on this site with both R1*-M173 chromosomes, E-M78 clusters and E-M34. So, the present author now reiterates what's wrong with his so-called "Asia-to-Africa back migration", which he seems bent on promoting, since otherwise would implicate European ancestry directly from Africa, which is known to get Eurocentrists' and closet-Eurocentrists' pants in a bunch.

Previously, when Cruciani (2002) thought he had come up with undifferentiated, upstream Hg R1* chromosomes, he considered it a possibility that this could be suggestive of African origin, since the African counterparts were phylogenetically more basal than his non-African sample collection; yet, this didn't phase him to entertain the alternative then, about back-migration to Africa, predicated on a flimsy case about Hg R, in its entirety as a family, not being as diverse in Africa as it appears to be in Asia. At the time, this was essentially Cruciani's sole argument for his preference of a back-migration scenario, which obviously contradicted the fact then, that his African samples were the ONLY ones which tested positive for the most basal R markers.

So now, he comes up with new markers, and tries to see if he can solidify his earlier rather debatable, if not flimsy, position. But even here, having sampled a number of Chadic-speaking populations in the central Sahel as a gesture of applying fine-tooth combing to the DNA sequencing of the Hg R chromosomes, particularly the perplexingly-unique African examples, he points out that the Hg R chromosomes bearing the "new mutations" he tested for are still more prevalent in Africa, and rarer in non-African areas. Yet, Cruciani wants to convince us that this is some sort of unequivocal proof that Africans must have attained it from back-migration, and he tries to reinforce this effort, by invoking early Holocene estimation dates. Also, contrary to Cruciani's mindset, it is not necessary for *all* the sub-clades of K to emerge in Africa, in order for the origin of K-M9 on the continent to be probable. Hg K's most immediate descendants like Hgs T, K1, K2...etc do not form monophyletic branching with respect to one another, but each of them form their own distinctive branch from the ancestral K-M9 node. Nor is it even necessary for the M9 mutation to have emerged in Africa, in order for R to emerge in Africa; humans are not static creatures. All that is needed, is for the P clade to have been present in Africa at some point in time. To the present author's knowledge, P has not been uncovered as a standalone clade [lacking downstream markers] anywhere. However, it is interesting to note that African R1*-M173 chromosomes were previously tested for the P25 mutation, and came up negative. What does this then mean? It means that while Africans carried rare Hg R1 chromosomes bearing the P25 marker, they also carried examples without the P25 marker [see Hassan et al. 2008, for example]. In other words, African R1-bearing chromosomes aren't homogeneous as Cruciani would perhaps like us to believe.

Furthermore, as the present author has noted here and elsewhere before,...

Interestingly, upon revisiting Wood et al. (2005), it should be pointed out that paraphyletic clade of R*-M207 was detected amongst some "Afro-Asiatic" African groups, along with the paraphyletic clade R1*-M173 [it is worth noting that Wood et al. implicate the Egyptian sample here as something other than that of Semitic speakers (Arabic)], while some Niger-Congo groupsthough in small frequencies [pooled] — tested positive for the paraphyletic R1b*, lacking the established downstream R1b markers. Henceforth, R*-M207, lacking downstream mutations have been identified in African groups via this study; and yes, the basic nodes of all presently known Hg R's downstream clades had been accounted for, which means that R*, as predicted above, is NOT relegated to the Indian sub-continent. All in all, this suggests that African Hg R pool is actually more diverse than many seem to think.

So once again, African R-bearing chromosomes lacking the P25 marker have been identified, whereas Cruciani's Hg R chromosomes all appeared to have tested positive for P25; his samples bearing the R-positive chromosomes only differed from subsequent downstream markers - presumably aside from one or more of those "new mutations" that Cruciani claims he had used in his DNA sequencing. African chromosomes transcend even the ancestral Hg R1* marker; the paraphyletic R* is also implicated, which is ancestral to R1* marker!

...but the present author has a hunch that Cruciani isn't done fine-combing Hg R chromosomes just yet, if he is to unequivocally prove that back-migration scenario he seems to so desire. So, watch this space, and please go over the cited R1*-M173 link(s) again, as it is constantly updated!
_________________________________________________________________
References*

As already cited.

Personal notes retrieved from elsewhere.

Additional reading:

R1*-M173 Chromosomes in Africa

More on R1*-M173 bearers 

Mitochondrial DNA M1 haplogroup: A Response To Ana M. Gonzalez et al. 2007

 *Last edited on 10/22/2010.

Saturday, September 19, 2009

E-M34: Designation as "African" presents a Dilemma?

Earlier on this year, the present author of this site had an exchange with a chat room regular and the author of a paper titled "Y Haplogroups, Archaeological Cultures and Language Families: a Review of the Possibility of Multidisciplinary Comparisons Using the Case of E-M35", going by the name of Andrew Lancaster, on issues pertaining to the origins and demic diffusion possibilities of E1b1b subclade 'E-M34'. There are some observers out there who basically prefer to treat E-M34 as an isolated [standalone] lineage on its own, away from all its other E-M35 siblings, and mute the fact that this lineage essentially signifies recent common African ancestry. In what appears to be ironic, sections of these same observes are inclined to use E-M34 as primarily a marker of "external gene flow" into Africa. To put the underlying reasoning by such observers to test, the present author of this site decided to query the aforementioned Lancaster on his views.

In the mentioned paper, Lancaster sees the E-M34 clade more as ultimately a marker of demic diffusion "into Africa" as opposed to "out of Africa"; he invokes geneticists Cruciani et al. (2004) as his primary reference-sources, to justify his viewpoints. Here, he recites the claim that from a distribution standpoint, E-M34 clusters appear to be absent in nations immediately neighboring Ethiopia [like Sudan], and the supposed greater intra-clade diversity found in the Arabian peninsula than in Ethiopia. When repeatedly told that the geographical location of the contemporary nation of Ethiopia need not be the original African territory of the African forerunners of E-M34 carrying Ethiopians, or that for E-M34 to be deemed "African", it need not be predicated on it having to have originated in what is now Ethiopia, and that instead these forerunners could have originated in a more northern latitude in the geographical sphere of the eastern Sahara, Lancaster's reaction is to present what is now part of the contemporary nation of Egypt as a "concession" on his part. According to this "concession", he is willing to give into the possibility that E-M34 originated in what is now part of Egypt and thereafter spilled over to the Levant to its east, and coastal north African areas to its west. He points to the relatively visible, not necessarily predominant, distribution of E-M34 markers in these areas, and in some cases, sporadic incidences of paraphyletic examples of E-M34. Lancaster seems to seize on the condition of "Semitic" speaking in Ethiopia as something that further justifies his viewpoint.

Lancaster's so-called "concession" revolving around an Egyptian origin is all fine and dandy, but even here, he refuses to see an Egyptian origin as essentially an "African" origin as well. He refuses to get in touch with the reality that Egypt is part of Africa, and therefore, that the two are not mutually exclusive of one another. Logic intimates that what is Egyptian is by default also African, but for some reason, when it comes to things African, such no-brainers suddenly belie logic. He insists that it would be better [on his account] to perceive Egypt in terms of the over-time-changing and subjective Eurocentric-created geopolitical constructs like the "Middle East" rather than the less subjective designator for the continent to which Egypt belongs. In other words, his "concession" has a precondition attached to it; that is, as long as Egypt is viewed as "Middle East", which is tacitly supposed to be mutually exclusive of "Africa". It is against this backdrop, he chooses to interpret an African origin as needlessly implicating "all of Africa"; such "problems" or "issues" of course, never arise when dealing with any other continent.

On the issue of distribution, Lancaster's recitation of authors [namely Cruciani et al. (2004)] who proclaim to have come up short where findings in territories immediately neighboring Ethiopia [like Sudan] is something that deserves closer inspection. Cruciani et al. (2004) themselves don't quite go out on a limb to rule out an "eastern African" origin, but point out two "observations" that point to, in their words, a "Near Eastern" origin:

Although the frequency distribution of E-M34 could suggest that eastern Africa was the place in which the haplogroup arose, two observations point to a Near Eastern origin: (1) Within eastern Africa, the haplogroup appears to be restricted to Ethiopia, since it has not been observed in either neighboring Somalia or Kenya (present study) or Sudan (Underhill et al. 2000).

A number of observations here: Firstly, it is fairly obvious that "eastern Africa" as used here, is a tacit reference to the "sub-Saharan" area of eastern Africa; for if that wasn't the case, then naturally, one would have to assume that Cruciani et al. (2004) are not informed about Egypt being located in "eastern Africa". Moreover, this would be at odds with Mr. Lancaster's "concession". Secondly, the authors here are obviously drawing a far-reaching conclusion from fairly narrow observations made from just two studies that they cite, one of which happens to be their very own—their then present study. The authors study did not include any sample from Sudan, leaving the authors to rely on a single older study.

A comprehensive look back at studies done in Sudan suggest that it is an area understudied, which is interesting, given "Western" academic circles' obsession with eastern African areas; there are very few studies [undertaken by elements of 'Western' academia] that have dealt with that territory, let alone comprehensive region-wide study of Sudan. In any case, if one were to take it as the absolute fact based on a few measly [however instructive] studies undertaken, E-M34 absence or rarity in immediately surrounding [Ethiopia] territories of the likes of Sudan, Somalia and Kenya presents another interesting case.

Like Egypt, territories of Sudan and Somalia are right by the Red Sea, and in many cases, however different the internal clusters, and/or distribution and frequency patterns of markers involved may be, have experienced demic diffusion events involving the same line of clades or macro-haplogroups that now find place on Ethiopian landscape. Ethiopia itself is now essentially a landlocked nation, with the parting away of Eritrea, underlying just how fluid and subjective geopolitical constructs can be, and hence, intellectually not economical to place one's bets [arguments] on purely geopolitical constructs. So, if it were a simple matter of gene flow from the Arabian peninsula or the Levant [seems to be Lancaster's leading impression] of the so-called "Near East", one would think that the probability of E-M34 chromosomes finding their way into Sudan, Somalia, Djibouti, Eritrea, as it has obviously done in Egypt and Ethiopia, should be reasonably high enough.

However, if the mutation itself occurred at some point somewhere in central-eastern Sahara, north of the equator, then it is certainly conceivable a community with a very modest effective population size could have taken a two-pronged dispersal: one in a direction towards the delta region of the Nile River Valley, and the other towards the Ethiopian region. There could have even been an additional one, headed westwards, along coastal north Africa. With such migration, it is not necessary for the migrants to have stayed put in what is now Sudan or say Somalia, and even if they had, negative random genetic drift on settlers forming a community(s) of fairly modest effective population size could have ensured that their numbers in these areas remain at undetectable levels, that is to say, one which could easily evade the foci of the selective and patchy sample undertakings by "Western" academic concerns.

Lancaster made a fuss about paraphyletic E-M34 clades having been detected in the so-called Near East, but not in Ethiopia, based on the few studies that make note of these incidences. As natural, and equally so, he was reminded of the other side of said observations: paraphyletic examples of E-M34 were for instance, noted in a Tunisian sample (Arredi et al. 2004), and an isolated incidence in southern Europe, Bulgarian sample, along with another single one in central Asia (Cruciani et al. 2004), but interestingly enough, not in the so-called "Middle East" either [as per both cited studies used as examples]. Needless to say, it would not make the least sense to pounce on an isolated incidence in a Bulgarian sample or one individual from Central Asia and draw a far-reaching conclusion that this must be the vicinity of where the E-M34 mutation first occurred.

Europe is not exactly the epitome of a comprehensive and wide-variety of distinctive E-M35 clades, and one can make the argument, though to a lesser extent than Europe, that the so-called "Near East" is not a garden of variety either, when it comes to E-M35 chromosomes. Africa, on the other hand, is an entirely different story...naturally. The point being, since it hasn't been phylogenetically demonstrated to date that E-M34 derives from any of the other known E-m35 derivatives in either the so-called Near East or Europe, Africa with its unsurpassed comprehensive range, does not run into that problem.

Furthermore, in many of the areas where E-M34 chromosomes had been detected, as related to Lancaster but not getting through to him, it has been found in tandem with other markers undeniably suggestive of most recent common African ancestry. An example of this is in the Levant, wherein paraphyletic R1 chromosomes [as earlier found in northern Cameroon] where observed in high frequencies in tandem with E-M34 chromosomes in Dead Sea Samples, which interestingly, had far lower Hg J markers than other neighboring so-called "Near Eastern" Semitic-speaking groups; conversely, said Dead Sea sample had much higher incidences of E-M34 than said neighbors, along with the X chromosome G6PD marker, generally stated to be restricted to African samples.

Lancaster somehow managed to mangle up the example, and interpreted it as one that supposedly relies on the notion that if said R1 chromosomes are shared with Africans, then it must necessarily follow that the E-M34 is "African". Continuing with Cruciani et al. (2004),...

(2) E-M34 chromosomes from Ethiopia show lower variances than those from the Near East and appear closely related in the E-M34 network (fig. 2D). If our interpretation is correct, E-M34 chromosomes could have been introduced into Ethiopia from the Near East. The high frequency of E-M34 observed for some of the Ethiopian populations could be the consequence of subsequent genetic drift, which can also explain the lower frequencies (2.3% [Underhill et al. 2000] and 4.0% [Semino et al. 2002]) reported for two large independent samples of Ethiopians.

While Cruciani et al. (2004) claim that the internal variation of Ethiopian showed "lower variances" than those from the so-called Near East, a close look at their own visual aid of the networks in question suggest something different: it shows little distinction between the level of distinctive branching within the Ethiopian index and that of the so-called Near Eastern examples. The distraction that Lancaster offers in reaction to this observation, was simply to query the present author of this blog as to whether he was questioning Cruciani et al.'s genetic credentials. Of course, that very idea is preposterous and immaterial, as a succinct and very specific observation was made about Cruciani et al. (2004) on the diagrammatic interpretation of the respective Ethiopian and "Near Eastern" E-M34 networks, which only needed a direct, and equally succinct and specific rebuttal to the contrary, if the dissident (Lancaster in this case) had one. The diagram in question was this:

Click on the image for better resolution

The subtext accompanied with the diagram reads:
Microsatellite networks of E3b haplogroups. A, E-M35*. B, E-M78. C, E-M81. D, E-M34. Reduced-median and median-joining procedures (Bandelt et al. 1995, 1999) were applied sequentially. A haplogroup-specific weight proportional to the reciprocal of microsatellite variance was used in the construction of the networks. The E-M78 unweighted network (not shown) gave the same quadripartite structure. Unassigned chromosomes (B) showed an intermediate position between clusters α and δ in the unweighted network. Microsatellite haplotypes are represented by circles, with areas proportional to the number of individuals harboring the haplotype. Branch lengths are proportional to the number of one-step mutations separating two haplotypes.

The diagram is there for anyone to examine him/herself, and so, if one wanted to make an argument counter to the one the present author of the blog makes, it should be a fairly straightforward undertaking, without beating around the bush with shallow distractions. The latter part [emphasized in bold] of the aforementioned "second" reasoning provided by Cruciani et al. (2004) just goes to show how much observations made in a particular study are greatly influenced by sampling selections and range by the respective authors of these studies; the differing observations attest to this. If the effect of genetic drift is to be thrown into the mix, as Cruciani et al. (2004) insinuate, then that takes us back to or only reaffirms the point made here earlier, about the effects of that same phenomenon on the demographic history of E-M34 migrants. Interestingly enough, the authors proceed with concluding their segment on E-M34 as follows:

From the Near East, E-M34 chromosomes could also have been introduced into Europe, possibly by Neolithic farmers, but the paucity of E-M34 chromosomes in southeastern Europe (Semino et al. 2004 [in this issue]; present study) weakens this hypothesis. Indeed, as for E-M78δ chromosomes, introduction of E-M34 from Africa directly to southern-central Europe cannot be excluded at the present.

The piece necessitates little further elaboration; it pretty much speaks for itself. The gem in it, of course, is that if E-M34 chromosomes introduced "directly" from Africa to southern Europe is more than probable and explains its distribution there, then why can the same not be true for the so-called "Near East"?

*According to Semino et al.'s report, there is microsatellite indication that much of Ethiopian hg J-M267 examples are of Neolithic provenance...
The majority of J-M267 Y chromosomes harbor the single-banded motif YCAIIa22-YCAIIb22 in the Middle East (>70%) and in North Africa (>90%), whereas this association is much less frequent in Ethiopia and only sporadically found in southern Europe. Considering the distribution of this YCAII single-banded pattern—which, besides the usual stepwise mutational mechanism, could be due to a stable mutational event (one locus deletion or a single-nucleotide mutation in the primer sequence)—we suggest that the motif YCAIIa22-YCAIIb22 potentially characterizes a monophyletic clade of J-M267...According to this interpretation, the first migration, probably in Neolithic times, brought J-M267 to Ethiopia and Europe, whereas a second, more-recent migration diffused the clade harboring the microsatellite motif YCAIIa22-YCAIIb22 in the southern part of the Middle East and in North Africa. In this regard, it is worth noting that the median expansion time of the J-M267-YCAIIa22-YCAIIb22 clade was estimated to be 8.7–4.3 ky, by use of the TD approach (see fig. 4 legend), and that this clade includes the modal haplotype DYS19-14/DYS388-17/DYS390-23/DYS391-11/DYS392-11 of the Galilee (Nebel et al. 2000) and of Moroccan Arabs (Bosch et al. 2001).
If true, this would mean that any "Afro-Asiatic" hg J-M267 from southern Arabia would have had to have been acquainted with the farming subsistence from the Levantine areas, and as such, certain Neolithic social terms associated with such economy would have been available. As noted here before, nothing comes to mind that suggests basic "Near Eastern" or "south Arabian" Neolithic-derived terms in Ethio-Semitic. Kivisild et al. are essentially treating hg J1-M267 as the effective marker for proto-Semitic speakers in Ethiopic populations, as opposed to E-M78 or E-M35 clades, which is odd, because the primary agents of spreading proto-Semitic or proto-Afrisan languages into the "Near East" and the Arabian peninsula in the first place would have largely been E-M35 carriers, who originate from an area where preponderance of evidence—including both genetic particulars and language diversity—places the origin of proto-Afrisan language phylum. This therefore puts hg J carrying groups in the "Near East" and elsewhere on the receiving end of "Afro-Asiatic" language acculturation, not the primary agents of it.

The structuring of hg J clades along linguistic lines within Ethiopian samples simply says that these groups likely merged together from distinctive demographic episodes; one involving the group predominantly comprising of proto-Ethiopic Semitic speakers—likely carrying both hg E-M35 clades and hg J clades—and the other,  predominantly Cushitic speaking groupsthat's just about it; it tells us very little about the specific direction from which the aforementioned linguistically-structured markers respectively arrived—be it from the north or from the southern Arabia, short of comprehensive comparative analysis at the molecular levels between the Ethiopic groups and geographically proximate, exotic, non-Ethiopic groups.

Kivisild et al. were compelled to make J1-M267 into THE telltale marker for the spread of proto-Semitic phylum into the African horn, because they recognized the low to absent incidences of E-M78 in south Arabian samples, which no less were not based on actual sampling of Yemeni population at the time of their observations, but at the same time they had to contend with linguistic reconstructions that place Ethio-Semitic languages into the southern branch of the Semitic phylum. For those who are bent on explaining away autochthonous coming about of Semitic languages on African soil, this element entices the cooking up of theories around an origin in the southern tip of the Arabian peninsula, no matter how tenuous.

One cannot also help but arrive at the conclusion that the presence of E-M34 clades in southern Arabia must have been elusive to the authors in question, and that it may well be serving as a marker of Afrisan diffusion into that region. In Cruciani et al.'s 2004 journal, which the authors rely on, not only had E-M34 markers been reported in the sole southern Arabian sample (Omani), but so had the E-M78 counterparts, and they occur in identical incidences. That said, E3b1c1-M34 chromosomes are visibly prevalent in Ethiopian groups, as they are across the whole stretch of northern Africa.

From the earlier mentioned Semino et al. (2004) study, as it concerns the compatibility of Ethiopian J1-M267 clades with the idea of their introduction by southern Arabians, particularly their nearest neighbors—the Yemeni, it was acknowledged that:
The lower internal variance of J-M267 in the Middle East and North Africa, relative to Europe and Ethiopia, is suggestive of two different migrations.  - Semino et al. (2004)
This revelation to the authors' above is consistent with those reported elsewhere, and may well prove instructive in the quest to determine the duplicity of Ethiopian hg J clades with those in southern Arabia, particularly those of Yemen:
At another extreme, the haplogroup distribution of Yemen shows very limited variation, particularly when compared to neighboring populations, Oman and UAE (3 versus 11 haplogroups each), whereas Qatar is intermediate with a total of seven haplogroups, four of which display frequencies of less than 3.0%. Although Qatar does not approximate the lack of diversity seen in Yemen, the two populations display affinities that are apparent in the MDS plot, in which populations of the Levant are interspersed among the South Arabian populations, with Qatar and Yemen segregating apart from both UAE and Oman. - Cadenas et al. (2007)
The authors figure that one of the underlying causes for this reduction in diversity of Yemeni Y-DNA gene pool, in addition to subsequent expansions masking earlier ones, could be a matter of a "high degree of consanguinity" within the population. Having said that, elsewhere, they wrote:
Median BATWING expansion times based on Y-STR data for the Omani (2.3 ky; 95% CI: 0.6–29.2) J1-M267 chromosomes4 indicate a more recent arrival to the South Arabian populations as compared to the older expansion times obtained for the Egyptian (6.4 ky; 95% CI: 0.6–278.5)4 and Turkish (15.4 ky; 95% CI: 0.4–604.8)12 representatives of this haplogroup. Conversely, in the present study, Y-STR age estimates based on the method described by Zhivotovsky et al46 generated much older values for the J1-M267 haplogroup in Yemen, Qatar and UAE (9.7 +/- 2.4, 7.4 +/- 2.3 and 6.4 +/- 1.4 ky, respectively) than seen in the Omani,4 consistent with an earlier arrival to the region during the Neolithic. The data suggest expansion from the north during the Neolithic (or perhaps more recently), which is also reflected in the lower STR variances in southern Arabia (0.14 for Qatar, 0.15 for UAE, 0.20 for Yemen and 0.27 for Oman4 versus 0.31 in Egypt4 and 0.51 in Turkey12). Subsequently, a series of recent demographic events may account for the high haplogroup frequency of J1-M267 in the populations from the present study.  - Cadenas et al. (2007)
Like Semino et al. (2004) and Luis et al. (2004) before them, these authors too note the higher intra-haplogroup variance in J1-M267 chromosomes in areas to the north of the southern Arabian territories mentioned here both in the "Middle East" and Northeastern Africa than those in populations of said southern Arabian peninsula areas. In light of this, it is important to reiterate, just as the said authors themselves did by citing Semino et al. (2004), that the Ethiopian hg J1 clade gene pool was even more varied than those from the "Middle East" and coastal Northern Africa.

Furthermore, just as the aforementioned authors in the 2004 publications note the older expansion ages for populations to the north of the more southward-oriented populations in the Arabian peninsula, the authors here too arrive at the same conclusion, noting that the expansions appear to have began from the Neolithic times onwards from the north to south along the Arabian peninsula. Yet again, Ethiopian hg J clades in turn show older expansion ages than sections of Northern African and "Middle Eastern" gene pool, which have been affected by more recent demographic events, as have the southern Arabian groups mentioned here.

The estimated upper-end expansion time frame of Yemen's hg J1 gene pool in particular is one that is not inconsistent with that generally associated with the spread of Neolithic farming subsistence, but the more internally more varied hg J1 clades of Ethiopia than those in Yemen (not to mention the distinctive aforementioned paraphyletic clades of Ethiopia), and the rest of the south Arabian groups described here, is inconsistent with an idea of introduction from Yemen, or any other southern Arabian territory for that matter. This is significant, considering that hg J has a considerable presence in Yemeni Y-DNA gene pool; 72.6% according to Cadenas et al. (2007).

The picture is no less different, when it comes to E1b1b1c (E-M123 or its subclade "E-M34")  chromosomes; while Cadenas et al. (2007) cited Cruciani et al.'s (2004) reckoning about the plausibility of Ethiopian E3b1c1-M34 bearing chromosomes arriving from the "Near East", they did not go quite as far as suggesting a "Near Eastern" origin for the clade in any context:
On the other hand, Cruciani et al57 have postulated that the E3b1c-M123 clade may have originated in the Near East, as its presence in East Africa is restricted to Ethiopia (11.2%). The median expansion time for M123 in Egypt is 10.8 ky,4 comparable to the estimated age of M123 STR variation obtained through the method described by Zhivotovsky et al46 for UAE (11.1 +/- 3.9 ky) and Yemen (10.6 +/- 4.1 ky), although allelic differences between these two populations indicate that they do not share a common ancestry. Recent archaeological finds supports a trading relationship between Mesopotamia and the Arabian Gulf region dating back to the Al Ubaid Period (~7000 yBP) as evidenced by the excavation of Ubaid pottery from Mesopotamia in UAE.8–10 Ancient maritime trade routes linking Mesopotamia to the Indus Valley included Dilmun (the island of Bahrain) and Magan (in the southeastern tip of the Arabian Peninsula). It is possible that the close ties between Mesopotamia with both the Nile River Valley and the ancient Persian Gulf region during the Neolithic helped disseminate these haplogroups- Cadenas et al. (2007)
In fact, the authors' language suggests acknowledgment of E3b1c-M123 as more of a marker of African ancestry than one of "back-migration":
The E3b1-M35 sub-haplogroups, M123 and M78, are believed to have spread from East Africa to North Africa and later expanded eastward through the Levantine corridor and westward to northwestern Africa. Although E3b1a-M78 data suggest that this dispersal occurred in both directions,4,34,47 E3b1c-M123 disseminated primarily to the east.4 The distribution of the E3b1-M35 derivatives in Yemen, Qatar and UAE agrees with their arrival by expansion via the Levantine corridor rather than through the Horn of Africa. This route is similar to general patterns of Levantine mtDNA gene flows during the Upper Paleolithic55 to the Neolithic.5,55 This is immediately apparent by the M35 profile of several East African populations. - Cadenas et al. (2007)
Having noted Cruciani et al.'s (2004) postulation, the authors merely note that the trade network between said regions may have facilitated the spread of E3b1c-M123, which was followed by its expansion downward in the Arabian peninsula, wherein it appears to have undergone multiple founder effect—and likely genetic drift thereafter—events, resulting in the patterns noticed in the Arabian peninsula, with different populations having different subsets of E3b1c1-M34 chromosomes, which of course, brings us right back to Cruciani et al.'s (2004) claim of relatively lower internal variation in the Ethiopian E3b1c1-M34 gene pool than those from the "Near East".

Cruciani et al. (2004) provided us with a map of E3b1c-M123 among other E1b1b1 markers, displaying the Y STR network, wherein they tell us that the Ethiopian examples are more closely related than the "Near Eastern" examples, and hence, lesser diversity thereof. As noted here before, an instant look at the map itself doesn't appear to invoke a sense of that much of a difference between the internal diversity of Ethiopian chromosomes and those of "Near Eastern" examples as far as the number of distinctive inter-connecting "branches" that respective haplotypes fall into is concerned, save to say that where said haplotypes are branched-out immediately from one another and having come from populations within the same region or general geography, the Ethiopian examples do appear to display more shorter-length branches in between them than those from the "Near East". The comparison based on the latter phenomenon though, doesn't come from a level playing field; the Ethiopian haplotypes are expected to show relatively shorter branches with respect to one another, because they are highly geographically-proximate populations of the same nation state, whereas those from the "Near East" were pooled from distinct geographical territories spanning the Asian Minor, the Levant all the way to the southern tip of Arabia.

As we've just seen from above, the "Near East" expansions of E3b1c1-M34, likely first in the northward-oriented territories therein, and then from there towards the south, was marked by multiple "founder effect" situations accompanied by genetic drift—positive or negative, resulting in different subsets of E3b1c-M123 developing internally within respective distinct populations of the region. A fairer assessment would be pooling *all* African examples together, and comparing them with the pooled "Near Eastern" examples. Cadenas et al.'s (2007) posting of internal-diversity of E3b1c1-M34 clades per region is consistent with previous data.

Furthermore, the studies posted here all, and more, keep citing that singular Underhill et al.'s (2004) one study wherein E-M34 was not detected in a Sudanese sample, around which Cruciani et al. (2004) raise their "Near Eastern" origin plausibility, for Ethiopian chromosomes. In that same study, interestingly, no hg J clades were observed in the Sudanese sample either; How is that for a reality check? Yet, other studies have noted hg J markers in Sudanese samples. Semino et al. (2004) for their part, refrained from inferring the origin of Ethiopian E3b1c1-M34 clades, only noting that:
The network of E3b1a-M78 and that of E3b1c-M123 are in agreement with the hypothesis of their ancient presence in the Near East and their subsequent expansion into the southern Balkans. The divergence time (TD) (Zhivotovsky 2001) between the Near East and European lineages has been estimated to a range of 7–14 thousand years (ky) ago. Cinniog˘lu et al. (2004) found a high degree of variance of E3b1c-M123 in Turkey, which has been interpreted as being due to multiple founders rather than a single early dispersal event that has remained geographically circumscribed- Semino et al. (2004)
In Turkey alone, we are confronted with a scenario of multiple founder situations; it has implications on the point made herein and that by Cadenas et al. (2007), about this phenomenon having an impact on the pattern of "internal" variation from across a fairly wide region spanning the Asian minor to the southern tip of the Arabian peninsula, when populations therein are pooled together and pitted against that of the more geographically constricted territory of Ethiopia. The high degree of internal variation in Turkey has been attributed to "multiple founders" from different demographic episodes, but Yemeni and other south Arabian populations, as we shall see below [and also revisit info above], display fairly low internal variation for their E-M34 markers, or conversely, high degree of homogeneity...

From Cadenas et al.'s (2007) posting:
As the MDS plot displayed a close affiliation between South Pakistan and North Iran and the former segregated away from the Gulf of Oman populations, the x^2-test was repeated excluding South Pakistan. Although statistically significant differences are still apparent for haplogroup E (x^2 = 10.170, d.f. = 2, P = 0.0062) and R (x^2 = 10.560, d.f. = 2, P = 0.0051), J (x^2 = 2.577, d.f. = 2, P = 0.2757) exhibits an even distribution among Oman, UAE and South Iran. However, a greater homogeneity is observed among the South Arabian populations of Oman, UAE and Qatar for haplogroups E (x^2 = 2.249, d.f. = 2, P = 0.3248), J (x^2 = 4 831, d.f. = 2, P = 0.0893) and R (x^2 = 0.308, d.f. = 2, P = 0.8573). The significant differences in frequency of haplogroups result in detectable clines moving from the South Arabian populations to South Iran and then South Pakistan (E: 18.8, 6.8 and 3.3%; J: 50.4, 35.0 and 25.3%; and R: 11.2, 25.6 and 46.2% for South Arabia, South Iran14 and South Pakistan,30 respectively).  - Cadenas et a.l. (2007)
The above show gradients, wherein hg E is greatest in southern Arabia and decreases as one proceeds northward to southern Iran, and then eastward to south Pakistan, and the same applies to haplogroup J, while the reverse trend is seen in hg R, with the lowest frequencies in southern Arabia. The piece above notes a greater loss of diversity in all three haplogroups involved when it comes to southern Arabia, compared to the other mentioned regions. Yemeni gene pool for these are yet even more limited in their diversity than the aforementioned south Arabian populations of Oman, UAE and Qatar. Recalling the piece cited earlier:
At another extreme, the haplogroup distribution of Yemen shows very limited variation, particularly when compared to neighboring populations, Oman and UAE (3 versus 11 haplogroups each), whereas Qatar is intermediate with a total of seven haplogroups, four of which display frequencies of less than 3.0%. Although Qatar does not approximate the lack of diversity seen in Yemen, the two populations display affinities that are apparent in the MDS plot, in which populations of the Levant are interspersed among the South Arabian populations, with Qatar and Yemen segregating apart from both UAE and Oman. - Cadenas et al. (2007)
Luis et al. (2004) posted an internal variance of  .41 for the Egyptian sample vs. the just .05 internal variance for the Omani sample, as it pertains to the E3b1c-M123 clade. Likewise, the internal variation of Egyptian J clades—J-12f2(xJ2-M172) and J*-12f2(xJ2-M172)—was .45 and .31 respectively, while those reported for the Omani sample were .40 and .27 respectively. There is apparently greater disparity between the reported values for the two samples in the case of the E-M123 marker than the J clades, but the common element here is the relative greater internal variation in the Egyptian sample vs. the Omani. On the other hand, Cadenas et al. (2007) report the following internal variance values for the following groups respectively: For UAE the value was .25 [E3b1c-M123] and .15 [ J1-M267], while for Yemeni, the values were .14 [E3b1c-M123] and .20 [J1-M267]. Qatar did not report for any E3b1c clades, but did have a value of .14 for J1-M267. The level of diversity demonstrated above in eastern African examples of E3b1c-M123 and J1-M267 markers, including those from Ethiopia, is inconsistent with a south Arabian origin. 

The plausible scenario for introduction of hg J1 clades in Ethiopian populations is more likely one wherein the J1 clades arrived early in the continent, whether due to in situ origin or back-migration, and was picked up by the ancestors of contemporary Semitic speaking groups of Ethiopia somewhere in the Sahara, noticeably more northward than their current habitat. However, even if one were to entertain a back-migration scenario as the causal factor for all African J1 clades for arguments sake, it appears to have arrived when the clades were in their very early stages of diversification, hence the abundance of paraphyletic clades, as discussed elsewhere here [link].

If the spread of the Neolithic farming subsistence played any role in all of this, then one would have to contend that it likely did not accompany some massive movement of people from the so-called "Near East", but rather, small scale migrations likely induced by increasing social organizations in both the so-called "Near East" and the Sahara, paving way to the opening of early and perhaps modest trade routes. This may have primarily involved fauna and possibly flora in the Neolithic context, between populations in each area with a view to liven up their preexisting stock with more choices or variety [with 'exotic' goods]. As such, would-be migrants who decided to settle in a new homeland, simply integrated into preexisting Saharan communities, and thereby not shifting the traditions of host communities in any considerable way.

We've already gone through the lack of immediacy between the so-called "Near Eastern" Neolithic farming "revolution" of economy therein, which is significant, considering that "Near Easterners" are right next door to the northeastern corner of Africa—one would expect entry into the Nile Valley through the Sinai corridor to have been more immediately accessible than many of the areas in mainland Europe, and hence, serve as one of the earliest entry points of demic-diffusion accompanying the spread of a tradition largely of a farming subsistence economy; several researchers claim that archaeological indicators suggest that large farming in northeastern Africa came in more or less about the same time as its spread into some areas in northern Europe, between ca. 8ky to 6ky ago or so, which makes it either on par and/or even later than certain southern areas of Europe. Yet, conversely, cattle domestication is said to have likely arrived before or about the same time as that in the so-called "Near East".

These developments don't square with massive intrusion of migrants into an area, thereby considerably shifting traditions in the destination point. It is against this backdrop that no considerable language shifts would have taken place either, which makes more sense in the Ethiopian context, considering the lack of tracing of "Near Eastern Neolithic-derived" terms in Ethio-Semitic languages. Now of course, the alternative to all this, is that hg J1 could have originated in the Sahara near the northeastern end of the African continent, and it certainly cannot be ruled out in the final analysis—just as the aforementioned matter of great internal diversity and paraphyletic clades demonstrate, but this is a matter that understandably doesn't sit well with many "westerners", just as the fact that E3b1a-M78 could be considered African ancestry [which if any, is usually begrudgingly accepted as African, preferably "northeast as opposed to sub-Saharan African"] and seeing as how both it and the J clade are widely acknowledged to be important markers of the diffusion of the so-called Neolithic farming subsistence into Europe.*

The argument revolving around the "Semitic" language family carries very little weight in the big scheme of things; it appears to be one that Lancaster heavily relies on. The Semitic language branch is after all, merely an offshoot of a language family that originated and spent the bulk of its evolution in Africa before spilling over to nearby territories.

Ethiopia has a distinction of being the most concentrated area for a fairly wide variety of a Semitic branch, which in this case, is what's deemed within "Western" academic circles as the south Semitic branch. When pressed on any justification for ruling out a possible direct African origin for the Semitic subphylum, Lancaster offered no specific or substantive explanation, other than to simply generalize that certain segments of "Western" academia profess a "Near Eastern" origin for the Semitic offshoot of the African language superphylum.

It is of note, that for all such speculation that Lancaster takes for granted as gospel truth, not one of these proponents have effectively demonstrated how [lexically and grammatically] and in what specific time frames Ethio-Semitic branch purportedly derived from the South Arabian branch. Sure, there are deemed to be some similarities here and there, which should be expected, given the history of bidirectional contact across the Red Sea, but this is far from establishing the particulars just mentioned, regarding time and nature of a purported derivation. Time can for example, be extrapolated from key root terms, with the aid of archaeology and other disciplines like bio-anthropology; examples of the sort, include proclaimed "Neolithic" terms. None has been identified, in the case of connections between Ethio-Semitic and known South Arabian dialects. As matter of example,

Andrew Lancaster writes:

But Lionel Bender (1997), a leading expert on Ethiopian languages, proposed a scenario upon linguistic grounds wherein Semitic languages originated in Ethiopia and crossed the Red Sea. We can note that although this linguistic theory would be in line with these very particular and unsurprising genetic links between the Horn of Africa and the Southern Arabian Peninsula, it does not correspond to much else in genetics or archaeology, and there is no reason to invoke such a theory in order to explain genetic links between the Horn of Africa and nearby Southern Arabia.

While Lancaster in his own little way seeks to downplay Bender's take on the geographic origin of Semitic, which in his very own words was proposed "upon linguistic grounds", by way of thereafter making references to its misplaced impact or implications on molecular genetics and archaeology that no specific personality had made in the first place, he provides no answers to the requested linguistic particulars just discussed above. His need to invoke Bender here, is to presumably discourage potential usage of Bender's proposal for the very thing that he admits is the case:

We can note that although this linguistic theory would be in line with these very particular and unsurprising genetic links between the Horn of Africa and the Southern Arabian Peninsula.

His real concern here, is that Bender's findings may be seized upon as yet another line of evidence that can be used to buttress an "African" origin point for E-M34, and its subsequent spilling over to nearby territories, as opposed to vice versa. That said, Lancaster's line of defense for not being able to substantively explain the nature and time-line of the genesis of a "Near Eastern" origin for the Semitic subphylum, culminating in Ethio-Semitic in the African Horn, is that he is not a professional linguist and has to rely on others; any clear-headed individual can see right through it as a dismissive line of defense, because if one is bold enough to take sides, then one ought to know the particulars of the arguments they are siding with. When pressed on it, Lancaster was not even able to offer further explanation for the immediately obvious loose ends that Chris Ehret et al's (2009) recent paper seem to be suffering from. The paper in question was: Bayesian phylogenetic analysis of Semitic languages identifies an Early Bronze Age origin of Semitic in the Near East, which itself is a noticeable departure from Ehret's own past viewpoints on the genesis of Semitic. Change of viewpoints is of course not unusual in academia, but it has to be accompanied with a well-defined intellectual justification, that is clearly laid out before the audience. The abstract put forward for the just-now-mentioned paper goes like this:

Kitchen A, Ehret C, Assefa S, Mulligan CJ. Department of Anthropology, PO Box 103610, University of Florida, Gainesville, FL 32610-3610, USA.

The evolution of languages provides a unique opportunity to study human population history. The origin of Semitic and the nature of dispersals by Semitic-speaking populations are of great importance to our understanding of the ancient history of the Middle East and Horn of Africa. Semitic populations are associated with the oldest written languages and urban civilizations in the region, which gave rise to some of the world's first major religious and literary traditions. In this study, we employ Bayesian computational phylogenetic techniques recently developed in evolutionary biology to analyse Semitic lexical data by modelling language evolution and explicitly testing alternative hypotheses of Semitic history. We implement a relaxed linguistic clock to date language divergences and use epigraphic evidence for the sampling dates of extinct Semitic languages to calibrate the rate of language evolution. Our statistical tests of alternative Semitic histories support an initial divergence of Akkadian from ancestral Semitic over competing hypotheses (e.g. an African origin of Semitic). We estimate an Early Bronze Age origin for Semitic approximately 5750 years ago in the Levant, and further propose that contemporary Ethiosemitic languages of Africa reflect a single introduction of early Ethiosemitic from southern Arabia approximately 2800 years ago. - abstract ends -

Supposing one were entertaining the authors' proposal, the 800 BC or so date, or even if one were to extend this date to the beginning of the south Arabian influences coinciding with the emergence of the the D'mt complex, logically suggests that any already differentiated and fully developed south Arabian "Semitic" language that diffused into the African Horn would have been adopted as is, meaning—in the very shape or form the language was brought in and expected to be no different, especially in the era it was introduced. However, from archaeology, and citing personal notes posted elsewhere:

"The inscriptions dating from this period in Ethiopia are apparently written in two languages, pure Sabaean and another language with certain aspects found later in Ge`ez (Schneider 1976). All the royal inscriptions are in this second, presumably Ethiopian, language." - Stuart Munro-Hay

What does this imply? "Pure" as used here, suggests that although "Epigraphic South Arabian" alphabets were used to convey a message in two different languages [one for south Arabian administrative centers, and the other for the comprehension of the locals (aka "Ethiopian" people, i.e. Eritreans, Tigrinya or what have you)], one of the languages on the inscriptions was the south Arabian language that was brought in along with South Arabian immigrants, while the other was a local language aka a local "Ethiopian" language.

Though both languages were written in ESA alphabets, evidence above suggests that the "Ethiopic" language very likely had grammatical features that clearly distinguished it from its Sabean/south Arabian counterpart. The aforementioned citation of Munro-Hay should be instructive, once again:

"...and another language with certain aspects found **later** in Ge`ez (Schneider 1976).

Now, Ge'ez is considered to be Semitic, which therefore follows that this ancestral language was the proto-Semitic language of Ge'ez.

Also, the era suggested in the abstract implies that the Neolithic J carriers of the region [Ethiopia, presumably migrants originally from South Arabia] didn't already speak some form of proto-Semitic or Semitic, but rather, that this only came into being around the time of the D'mt complex, give or take.

Now of course, the authors of the study at hand could attempt to move their dates and make it coincidental with these Neolithic era groups, but they would have to come up with a good deal of "south-Arabian" imported Neolithic root terms for the Ethio-Semitic branch, which hasn't been produced to date, that comes to attention, especially given that the Neolithic in the African Horn has been more linked to those of the Nile Valley in the Sudanese region, in terms of influences, than those in the Levant or south Arabia as sources of inspiration.

Furthermore, we are told:

"another language with certain aspects found later in Ge`ez (Schneider 1976). All the royal inscriptions are in this second, presumably Ethiopian, language." - Stuart Munro-Hay

The emphasized bit goes right back to the following, as already stated herein:

[One for south Arabian administrative centers, and the other for the comprehension of the locals (aka "Ethiopian" people, i.e. Eritreans, Tigrinya or what have you)], one of the languages on the inscriptions was the south Arabian language that was brought in along with South Arabian immigrants, while the other was a local language aka a local "Ethiopian" language.

If an observer takes issue with assigning "African origin" to E-M34 even as he/she professes to concede to an "Egyptian origin", then they are most surely suffering from the same psychologically-seated self-contradictions as Mr. Lancaster. It found expression in his debate etiquette, which visibly devolved for the worse, bordering juvenile at times as he sought to threw in off-topic distractions and playing the role of multiple personalities—doubling as a regular poster under his regular or actual name, and suspiciously, as "a moderator" with a pseudonym who only appears when the heat is being turned on Lancaster, as his viewpoint is put through its paces. It is not that Lancaster does not see a very compelling argument for E-M34 as essentially an African marker or lineage, it is just that he stigmatizes "Africa" and turns anything rightfully associated with it into something offensive [to him]. Presents a dilemma? Far from it; an African origin of E-M34 is more than compelling!

As regularly advised on this site, lookout for future updates.
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References*

— As noted in the body of the passages above.

— The passage placed in between two ' * ' signs was borrowed from a later posting [link] than the present one, because of its relevance to the discussion at hand.

—Semino et al. (2004), Origin, diffusion, and differentiation of Y-chromosome haplogroups E and J: inferences on the neolithization of Europe and later migratory events in the Mediterranean area.

—Cruciani et al. (2004), Phylogeographic Analysis of Haplogroup E3b (E-M215) Y Chromosomes Reveals Multiple Migratory Events Within and Out Of Africa.

—J.R. Luis et al. (2004), The Levant versus the Horn of Africa: Evidence for Bidirectional Corridors of Human Migrations.

—Cadenas et al. (2007), Y-chromosome diversity characterizes the Gulf of Oman.

—*Personal notes taken from notes dated to 2009 and 2010.

Monday, April 27, 2009

DE* as "Last Refuge" of Sects so psychologically troubled by African Ancestry?

The purported finding of DE* paraphyletic haplotypes in only 2 Tibetan sample candidates appears to have caused hysterical excitement in certain quarters, specifically amongst sects of individuals who are psychologically and emotionally tormented by the prospect of African ancestry in their "homelands". But this excitement is emotionally driven, and just that. As such, intellectual engagement gives way to religious cultism as the medium of self-expression. But let's just examine how much or what really lies herein that is worth being hysterically excited over:
  • DE* is a descendant clade of M168. M168 is undoubtedly African; this fact alone makes it more than probable that this place [Africa] is also likely where DE* emerged.
  • DE* is more common in Africa than outside of it -
It has been identified in African samples in more than one accasion in separately-conducted studies, having been identified in 5 Nigerian sampling candidates in one study, *1 in an Egyptian sample [see "Miscellaneous notes" below] and 1 Guinean individual in another . On the other hand, it had purportedly been identified in only 2 Tibetan sampling candidates. So we have 6 to 7 African cases vs. 2 Asian cases.
  • DE*'s internal phylogeny is more diverse and widely distributed in Africa -
Considering the greater internal phylogenetic branching of haplogroup E vs haplogroup D, it can be suggestive of either 1) longer time-depth for haplogroup E explosion/expansion, and hence, implicating DE* being around longer in Africa, as the homeland of haplogroup E ...

Or

2) that the haplogroup E lineage experienced an explosion that the D counterparts did not achieve in more or less the same time depth. The question becomes: What could account for this?

Either way, with fact being that African Hg E internal phylogeny is more elaborate than Hg D, the end result suggests that the intensity of such intra-E phylogenetic explosion seems to have had some level of erasing effect on DE* distribution. Given the greater pressure, due to greater demic explosion brought to bear on preexisting DE* in Africa — mainly by its own sub-phylogeny — than that which would have been the case in Asia by the YAP+ counterpart sub-phylogeny there, it's amazing that DE* is relentlessly visible enough in the African gene pool, as demonstrated by its greater chance detectability here than elsewhere, including Asia. This suggests that DE* would have been more widely distributed in Africa than in Asia, having been able to withstand greater pressure from greater subsequent demic expansion of Hg E phylogeny than that involving Hg D phylogeny, respectively in Africa and Asia.

The distribution and internal branching of Hg D suggests, on the other hand, that it involved lower scale dispersal of Hg D*, which were relatively more controlled in their subsequent expansion. The distribution pattern for instance, shows that the major subclades of D in different territories are highly differentiated and generally sharply geographically-structured, being confined to territorial spheres. At least that is the image reflected, if one goes by what's professed in the ISOGG.org website, whatever may be said of the credibility:

Sub-group D1 (D-M15) is seen in Tibet, Mongolia, Central Asia, and Southeast Asia, and the sub-groups D* (D-M174) and D3 (D-P47) are seen in Central Asia. The sub-group D2 (D-M55) is seen almost exclusively in Japan.

Hg D* is presumably also identified in the Andaman Islands.
  • A hypothetical Hg DE* back-to-Africa migration seems to have been elusive in leaving genetic tracks behind, presumably from south Asia to Africa -
The supposed back-migrants would seem to have left no genetic tracks behind in a hypothetical destination from southern Asia via the Arabian peninsula, eastern Africa through to African interior, in a hypothetical back-to-Africa migration scenario. If they did, then it had been thoroughly erased by multiple demographic shifts. Hg D's distribution in south Asia, with rare to no presence in territories between that region and Africa, is however explained by founder effect of OOA migrants, already carrying Hg DE* amongst them.

Chandrasekar's speculation is highly questionable for the same reasons just stated above; see:

Some of the YAP insertion chromosomes without the M174 mutation reached the Mediterranean via Central Asia and gave rise to the E lineage with mutations at M40 and M96 (~31 000 years ago; Hammer et al. 1998). This E lineage back-migrated to Africa through the Levant as hypothesized by Hammer et al. (1997) and Altheide and Hammer (1997).

Hg D is rare to absent in the Levant, and conversely, Hg E is virtually rare to absent in populations that do carry Hg D.

Furthermore, Hg E's presence in the so-called Near East, including the Levant and Europe, serves as gene flow from Africa, because Africa is where the entire Hg E phylogeny occurs, not the Levant. All upstream Hg E markers are exclusively found in Africa, and essentially none in the Levant.

The so-called Near East has far much lower frequencies of Hg E than in mainland Africa, and all of these happen to be subclades of African counterparts. Much of these subclades are relegated to the P2 (PN2) phylogeny. Upstream PN2 clades as generally known, only occur in Africa.

Revisiting Chandrasekar's post again,...

Some of the YAP insertion chromosomes without the M174 mutation reached the Mediterranean via Central Asia and gave rise to the E lineage with mutations at M40 and M96 (~31 000 years ago; Hammer et al. 1998).

It is also of note that Chandrasekar conveniently ignores that DE* has been found in Africa as well, but in even greater frequencies than his personal favored region [as noted in the second point above], i.e. Asia, not to mention that it is essentially non-existent in the so-called Mediterranean or the Levant. With DE* being in Africa, it is not necessary for Hg E to have come from the Levant, for reasons just mentioned and the ones immediately above this last Chandrasekar citation. Instead, Chandrasekar relies heavily on outdated studies, when Hg E phylogeny, as with many others, were in their early stages of being resolved.

His statement above, about "some of the YAP insertion chromosomes without the M174 mutation" has also implications that Chandrasekar seems to have overlooked:
  • Common sense intimates that any hypothetical DE* back-to-Africa migration — and it would have to have been major enough — would have been pooled from a newly situated migrant group. The keywords here: "newly situated".
Recalling Weale et al....

the presence of the DE* haplogroup has the effect of forcing an earlier date for the most recent common ancestor of all African YAP chromosomes. This reduces the possible time window within which a back-migration to Africa could have occurred under the scenario of an Asian origin for YAP. - Weale et al. 2003, Rare Deep-Rooting Y Chromosome Lineages in Humans.

Indeed! The presence of DE* in Africa suggests that this lineage was in place very shortly after its emergence. The OOA migrants had just recently left Africa for a reason; what on earth would these folks, who had just arrived, go back to Africa for, and at such a gruesomely long distance from a south Asian refuge? Pending tangible evidence of a compelling motive, it makes little sense.

And even if one were to take a hypothetical Asian origin of DE* for granted, based on skin pigmentation allele examinations, the original carriers of these markers would have closely resembled contemporary "black Africans", and even then, Hg E would still not be Asian [considering points above].

Let's face it; it's really not all that complicated: It just so happens that Hg D exists in Asia, while Hg E plays a dominating role in Africa, well, because DE* markers were present in both. Simple enough, isn't it?!

Neither territory has the other respective sub-clade lineage, because these emerged after OOA migrations, understandably.

Not sure why finding DE* therefore, surprises anyone. It's the only way D could have arrived in south Asia sans E; thus, DE* chromosomes brought in from Africa would have to have been around, in order for D to emerge, there is no other way around it. It is also the reason one finds DE* in both Africa, the origin point of destination, and Asia, the destination. However, instead of looking at it that way, some complicate things for themselves, and say that in order for DE* to be in Asia, it surely must have emerged there, and that there is no other way around that.

The most parsimonious explanation generally tends to reduce the number of questions for each answer that it provides than the alternative. In this case, an African origin entailing DE* dispersal in a OOA migration event, paving way for a founder effect situation in southern Asia is the most parsimonious. All things considered [from above], there really is little for the aforementioned sects to be cheerful about, at least from the intellectual side of things, as opposed to the religiously-motivated or plainly wishful end!
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Miscellaneous notes:

A lost gem?

The following recently grabbed the attention of the present author of this blog; the abstract goes like this:

The geographic location of Egypt, at the interface between North Africa, the Middle East, and southern Europe, prompted us to investigate the genetic diversity of this population and its relationship with neighboring populations. To assess the extent to which the modern Egyptian population reflects this intermediate geographic position, ten Unique Event Polymorphisms (UEPs), mapping to the nonrecombining portion of the Y chromosome, have been typed in 164 Y chromosomes from three North African populations. The analysis of these binary markers, which define 11 Y-chromosome lineages, were used to determine the haplogroup frequencies in Egyptians, Moroccan Arabs, and Moroccan Berbers and thereby define the Y-chromosome background in these regions. Pairwise comparisons with a set of 15 different populations from neighboring European, North African, and Middle Eastern populations and geographic analysis showed the absence of any significant genetic barrier in the eastern part of the Mediterranean area, suggesting that genetic variation and gene flow in this area follow the "isolation-by-distance" model. These results are in sharp contrast with the observation of a strong north-south genetic barrier in the western Mediterranean basin, defined by the Gibraltar Strait. Thus, the Y-chromosome gene pool in the modern Egyptian population reflects a mixture of European, Middle Eastern, and African characteristics, highlighting the importance of ancient and recent migration waves, followed by gene flow, in the region.

Source: Y-chromosome analysis in Egypt suggests a genetic regional continuity in northeastern Africa

by Manni et al. - 2002

For the complete journal, click here

The piece has raised some questions as to whether the YAP+ chromosomes in "some East Asian populations, such as the Japanese and Tibetans" is the same one identified in the Egyptian sample, i.e. essentially "Hg D", since this is largely the only YAP+ type found in said groups. The answer: Not necessarily, since the authors tested for YAP+, which is shared between Hgs D and E. The Egyptian YAP+ was very likely a paraphyletic chromosome that did not test positive for Hg E*, you know, just like how Hg DE* is devoid of the downstream characteristic markers of Hg E*. The 12f2 marker tested here more than likely refers to Hg J, which in this journal is designated as Hg 9. The nomenclature used here is apparently outdated [after all, this is a 2002 study we're dealing with here], but the finding of an upstream YAP+ chromosome that didn't belong to Hg E (as denoted here by SRY8299) is interesting nonetheless, because it adds to that theme of the unparalleled richness of Hg DE and derivatives on the African continent, as well as the distribution of the upstream DE* clade being *predominantly* an African 'thing'. So, in light of this, Egypt can now be added to the list of African territories wherein rare Hg DE* chromosome appears, a list which has no peers anywhere else where Hg DE* is concerned!

"haplogroup CF and DE molecular ancestors first evolved inside Africa and subsequently contributed as Y chromosome founders to pioneering migrations that successfully colonized Asia. While not proof, the DE and CF bifurcation (Figure 8d ) is consistent with independent colonization impulses possibly occurring in a short time interval."

Source: Use of Y Chromosome and Mitochondrial DNA Population Structure in Tracing Human Migrations

by Peter A. Underhill , Toomas Kivisild - 2007

A nutshell!...of what has essentially been more elaborately demonstrated about said markers on this site. The present author of this blog has not yet come across a single genetic journal that says differently about haplotype CF origin.

Sunday, January 27, 2008

P2 Clades: The Arrival of E3a and E3b Haplogroups

The MAJOR PN2 CLADES - E3a and E3b haplogroups: Investigating the backdrop against which they came about.

Recently, it has been proposed that E3b originated in sub-Saharan Africa and expanded into the Near East and northern Africa at the end of the Pleistocene (Underhill et al. 2001). - Cruciani et al. 2004, Phylogeographic analysis of haplogroup E3b...

We hear much about E3b and E3a haplogroup bearing populations in Africa, the major haplogroups on the African landscape today, but when and where did these lineages likely come about?

Here is what the present author of the blog thinks occurred, based on the information available to the author:

Between 23 and 18ky ago—Ogolian period begins, which coincides with and is likely connected to the LGM weather situation.

23,000 BP ~ 21,050 BC: "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 ]

—Much of North Africa and the Sahara are characterized by adverse weather conditions, with much of the region turning arid. The Sahara at this time, extends south beyond its current boundaries to a certain point, possibly a little beyond the Niger bend.

Arid conditions extend all the way to the "horn" coast of the African Horn region, possibly encouraging populations to reside more inwards—away from that horn-shaped coastal region; rather, likely towards the region straddling southern Sudan, Ethiopia, Kenya and Uganda or even further—region straddling Uganda, Kenya, and Tanzania.

—PN2 clade (E3) bearers in the vicinity of the Sudanese-Central African Republic -Ugandan-Kenyan region give rise to E3a ~ between 21 and 18 ky ago [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. At this time, it was likely the M78 derivative that came about ~ between 19 and 15 ky ago. It was also likely during this period, that some E3b-M35 variants spilled over to the "southwest Asia", which would be identified as E-M34. The E-M78* likely arose somewhere in the bidirectional-migration route between Northeast and sub-Saharan East Africa; this location was likely in the region straddling upper Egypt and Sudan of the eastern Sahara, amongst earlier E-M35 migrants from sub-Saharan East Africa. These M78 bearers were increasingly pressured to move further south due to progressive aridity, possibly as far as Uganda-Kenya and/or Tanzanian general region.

—The E3a bearing group would proceed westward, perhaps meeting groups of earlier lineages at the Shum Laka region of Cameroon, whereby quartz micro-lithic culture had already been in place by around 30 ky ago, hence preceding the rise of E3a common recent ancestor. But this group wouldn’t stay put here, at least not every section of it; they’d proceed to the savanna, grassland or vegetation holdouts in West Africa beyond the then boundaries of the Sahara. This probably occurred some time between 15ky and 13ky ago. During this period, as the Saharan aridity began to gradually slacken, some E-M78 bearing proto-Afrasan speaking nomads likely made their way into the Levant via the Sinai corridor.

Others taking refuge in the Cameroonian savanna-tropical forest general region probably followed suit, that is—after the aforementioned initial batch of migrants [bearing E3a descendants]; or else, the same group of people [from the initial migrants] shifted locations along the west African vegetation belts, once it became apparent that the far western reaches didn’t have much to offer, but the water system [as part of the Niger River]—however relatively shallow or what not—offered something additional. Finally, when the conditions in the Sahara were turning around for the better, starting between ~ 12ky and 11ky ago, these migrants would proceed northward, leaving the sort of trails that find expression at Ounjougou—Mali.

10th millennium BC ~ 12ky ago: At Ounjougou—"It is not until the Holocene and the return of humid climatic conditions, beginning in the 10th millennium BC, that it is possible to again observe evidence of human occupation." — Aziz Ballouche [see: Link ]

"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...

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 ]

It's very probable that this E3a bearing group(s) came into contact with the then wandering earlier-inhabitants of west Africa, who would have been pressured to move southward beyond the then Saharan desert boundaries, due to progressing aridity of the Ogolian period. These groups could have brought their central-Saharan pottery [e.g. found in Niger] traditions with them [developed perhaps sometime during the transitioning period to the wetter phase of the Sahara], just as the E3a bearing group(s) brought the microlithic traditions that they possibly picked up in the vicinity of the Shum Laka region [see above excerpt carbon dating estimations of finds] …and/or else…the new migrants produced their own versions of pottery in their new found location [as it is not noted whether these pottery had affinities with examples found in the aforementioned central Saharan region], at a time when it was trendy to carry stuff in pottery ware in the Saharan-Sahelian zone, with the filling up river systems due to the Monsoon rains.

The 10,000 and 9,000 BC (Phase 1 of the Holocene in Ounjougou): "The first sedimentary sequence of the Holocene can be observed at the Ravin de la Mouche. It's a channel dug into yellow Pleistocene silt and filled with coarse grained sand and pebbles. As a chronological reference for the upper levels of this early Holocene site, we hold ten radiocarbon dates between 9400 and 8400 BC cal. The associated lithic industry evidences predominantly a unidirectional mode of debitage. But also other technologies, such as bipolar on anvil or multidirectional, have been applied by the Early Holocene population. The raw material mainly used was quartz. The typological range consists of small retouched flakes, geometric microliths and perçoirs, but also of continuously retouched bifacial arrowheads and backed points." — Human population and paleoenvironment in West Africa [see: Link]

"By" 11,000 years BP ~ by 9050 BC:

"The age of the sediment in which they were found suggests that the six ceramic fragments discovered between 2002 and 2005 are at least 11,400 years old. Most ancient ceramics from the Middle East and the central and eastern Sahara regions are 10,000 and between 9-10,000 years old, respectively." — Human population and paleoenvironment in West Africa [see: Link]

By the 'beginning' of 8,000 BC: "Outstandingly, there has been evidence of the presence of pottery and seed grinding implements since at least the beginning of the 8th millennium BC. It is therefore the oldest site. The eighth millennium (Phase 2 of the Holocene in Ounjougou) known of this socio-economic type in sub-Saharan Africa...

The pottery and the seed grinding implements of phase 2 of Ounjougou are the oldest artefacts of this type known at present in sub-Saharan Africa. To current knowledge, the pottery of Ounjougou could either have been invented in the actual Sudano-Sahelian zone or been imported from the Central Sahara, where there has been evidence since the ninth millennium BC. Still, the oldest pottery known in the Sahara, from the site of Tagalagal in Niger, is already quite diversified at the moment of its appearance, possibly meaning that the technique has been introduced.

The lithic industry of the phases 1 and 2 on the other hand shows similarities to both more southern and Saharan industries. Quartz microliths, obtained through bipolar debitage on anvil, are a characteristic of the West African techno-complex according to Kevin MacDonald. Bifacially retouched arrowheads, in contrast, are specific for Saharan production." — Human population and paleoenvironment in West Africa [see: Link]

"The eighth millennium (Phase 2 of the Holocene in Ounjougou): The subsequent Holocene sequence is well documented by two principal sites, the Ravin du Hibou and Damatoumou. The archaeological levels can be quite clearly chronologically placed by means of a date obtained through OSL measurements (9420±410 Ka) and seven radiocarbon dates (between 8000 and 7000 BC cal). The lithic industry, exclusively quartz, is characterised by unidirectional, bidirectional and peripheral debitage, as well as by bipolar on anvil. There are essentially microlithic tools: perçoirs, backed points, notched pieces, denticulates, scrapers, retouched flakes and geometric microliths. Some small bifacially retouched arrowheads were also found on those sites. At the Ravin du Hibou, seven sherds have been found during excavation. They are heavily fragmented and thus preventing the reconstruction of the form of the vessel. Quartz has always been used as a temper. In just a single case, grog has been used in addition. Two shards show identifiable decorations. Two different techniques have been used: A rolled impression, possibly made with a peigne fileté souple or with a cordelette, and a simple comb impression. There were also seed grinding implements discovered at the Ravin du Hibou, a fragment of a seed grinding stone and a cylindrical upper grinding stone." — Human population and paleoenvironment in West Africa [see: Link]

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On the DNA side:

If we look at the samplings undertaken thus far, the west African populations on Atlantic-bordering west coasts—like the Senegalese samples, these groups undoubtedly have amongst the highest frequencies of E3a lineages, but there is something to be discerned: These groups largely carry M2, P1, and M180 lineages devoid of the M191 mutation, perhaps indicating the earlier E3a bearers, while many of the Bantu speaking groups of central, east and southern Africa carry those 191 derivatives:

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. — Cruciani et al. 2002

The above suggests that the oldest E3a bearing population(s) ultimately moved to the far west corner of the continent.

From Semino et al. 2004, we have:

It is also of interest, that the Senegalese samples have higher E3* frequency, which attains its highest frequency in Ethiopian populations, than the Bantu speaking groups, where the only group tested positive, was that of the South African Bantu sample:

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 Senegalese sample also bears the E-M.35* 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%

E-M78 in descending order….

Arab Morocco = 42.9%, Oromo = 35.9%, Amhara = 22.9%, Sudan =17.5%, Tunisian = 15.5%, Berber (Southern Morocco) = 12.5%, Arab (Morocco) = 11.4%, Berber (Morocco) = 10.9%, Algerian (32) = 6.3%, Berber (north central Morocco) = 1.6%, North Cameroon = 1.3%, Senegalese =.7%

E-M81 in descending order…

Saharawish (North Africa) = 75.9%, Berber (Morocco) = 68.7%, Berber (north central Morocco) = 65.1%, Berber (southern Morocco) = 65%, Algerian = 53.1%, Arab (Morocco) = 52.3%, Arab (Morocco) = 32.6%, Mali = 29.5%, Tunisian = 27.6%, Sudan = 5%, Senegalese = .7%

E-M33 in descending order…

Mali = 34.1%, North Cameroon = 7.9%, Senegalese = 5%, Burkina Faso = 3.8%, Saharawish (North Africa) = 3.4%, Berber (north‐central Morocco) = 3.2%, Sudan = 2.5%, Berber (Morocco) = 1.6%

E-M75 in descending order…

Bantu (South Africa) = 15.1%, Burkina Faso = 11.3%, Khoisan (South Africa) = 4.6%, Sudan = 5%, North Cameroon = 3.3%, Senegalese = 2.9%, Ethiopian (Oromo) = 1.3%

Looking at this data, among predominantly E3a-bearing Niger-Congo language speakers, Senegalese groups have the highest E3* frequency, as well as E-M35*. It follows the North Cameroon sample in this instance, in the E-M78 frequencies - though I’m not sure if those North Cameroon samples comprise of Niger-Congo speaking groups, Nilo-Saharan or some other language phylum group. In west Africa, it succeeds only Mali [and Niger, which wasn‘t included in this sample]—as one of the areas which have considerable Niger-Congo speakers—to have E-M81 bearing candidates, but then, Mali is also well known for its Saharan Tamazight speakers.

In reference to the above, some might look at a lineage as, say E-M78 and imagine it to be a trace of interaction with Saharan or coastal North African Afrasan speaking groups, but microsatellite inspection would indicate otherwise:

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 [b]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.


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, 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.

http://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/production/ajhg/2004/74/5/386295/images/medium/fg3.gif Source: Semino et al., Origin, Diffusion, and Differentiation of Y‐Chromosome Haplogroups E and J, 2004.

Some time during post 11ky ago expansions into the wet Sahara, before its return to aridity, with activity going on across the Saharan expanse, like cattle domestication for example, E3a bearers spread well into central-east Sahara. It was likely during this period that HbS mutations were localized, with the oldest E3a bearing groups nearer to the Atlantic-hugging west coasts bearing the Senegalese haplotype, while the Benin haplotype was able to have a more far-reaching expansion northward and northeast ward, due its situation in Niger River Valley vis-à-vis North Africa and the rest of the Sahara.
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Additional references to those mentioned in the body of the post:

*Semino et al., Origin, Diffusion, and Differentiation of Y‐Chromosome Haplogroups E and J, 2004.

* http://www.esd.ornl.gov/projects/qen/nercAFRICA.html

*Knight et al. 2003 : http://www.bec.ucla.edu/papers/Mountain_3-7-05.pdf

*Cruciani et al. 2004, Phylogeographic analysis of haplogroup E3b.

* Cruciani et al. 2007, Tracing Past Human Male Movements in Northern/Eastern Africa and Western Eurasia: New Clues from Y-chromosomal Haplogroups E-M78 and J-M12.