Monday, February 2, 2009

Comments on Battaglia et al. 2008: Y-chromosomal evidence of the cultural diffusion of agriculture in southeast Europe

The objective here is to dissect and analyze Battaglia et al.'s study. Immediately below, we have the abstract:

Battaglia et al.

Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy.

The debate concerning the mechanisms underlying the prehistoric spread of farming to Southeast Europe is framed around the opposing roles of population movement and cultural diffusion. To investigate the possible involvement of local people during the transition of agriculture in the Balkans, we analysed patterns of Y-chromosome diversity in 1206 subjects from 17 population samples, mainly from Southeast Europe. Evidence from three Y-chromosome lineages, I-M423, E-V13 and J-M241, make it possible to distinguish between Holocene Mesolithic forager and subsequent Neolithic range expansions from the eastern Sahara and the Near East, respectively. In particular, whereas the Balkan microsatellite variation associated to J-M241 correlates with the Neolithic period, those related to E-V13 and I-M423 Balkan Y chromosomes are consistent with a late Mesolithic time frame. In addition, the low frequency and variance associated to I-M423 and E-V13 in Anatolia and the Middle East, support an European Mesolithic origin of these two clades. Thus, these Balkan Mesolithic foragers with their own autochthonous genetic signatures, were destined to become the earliest to adopt farming, when it was subsequently introduced by a cadre of migrating farmers from the Near East. These initial local converted farmers became the principal agents spreading this economy using maritime leapfrog colonization strategies in the Adriatic and transmitting the Neolithic cultural package to other adjacent Mesolithic populations. The ensuing range expansions of E-V13 and I-M423 parallel in space and time the diffusion of Neolithic Impressed Ware, thereby supporting a case of cultural diffusion using genetic evidence.

The Sorenson Molecular Genealogy Foundation (SMGF) produced a review article of the study in question, and it might well be instructive to go over aspects of it:

Genetic research by the Sorenson Molecular Genealogy Foundation (SMGF) and scientists from ten organizations in Europe and the U.S. shows human groups with the deepest roots in southeastern Europe were not pushed out by an incoming wave of farmer-colonists as agriculture first spread into Europe. Instead, indigenous Europeans with a hunting and gathering lifestyle adopted agriculture when it was introduced by settlers from the Middle East. The study was published in the Dec. 24, 2008 online issue of European Journal of Human Genetics...

There aren't exactly that many advocates out there, who suggest that European populations were "replaced" by incoming Neolithic farming communities; but rather, that the latter were absorbed into the European population. Where have these people been all this time? At any rate, it goes onto say this:

First, the European DNA groups, haplogroups I and R, make up about 60 percent of today’s population in southeastern Europe and represent some of the earliest modern humans to have occupied Europe, stretching back into Paleolithic times.

Second, haplogroup E entered southern Europe from Africa’s eastern Sahara and became established in the region roughly 10,000 years ago.

Third, haplogroup J is Middle Eastern and likely introduced agriculture into southeast Europe around 8,500 years ago.

Pay attention to the last piece; there is no mention of J *and* E; just J alone, in the invocation of the introduction of agriculture into southeast Europe.

Now, observe:

Both of the two later-arriving lineages, haplogroups E and J each make up 20 percent or less of the region’s population.

Lineages E and J are found predominately in the southern part of the Balkans, the region where Middle Eastern immigrants would have entered the area and where the first pottery associated with a farming society in the region is also observed.

The study proposes that the haplogroup J lineage introduced farming to the inhabitants of the southern Balkans represented by haplogroup E.

Members of haplogroup E subsequently transmitted the farming technology along the Adriatic where it was readily adopted by indigenous Europeans represented by haplogroup I.


While it is acknowledged that haplogroup E and J arrived in from non-European sources, it is only in southeast Europe, do we come across mention of haplogroup E carriers, who are not presented as the "co-agents" of the initial introduction of agriculture into Europe, but rather, served as the "middle-men", so to speak, who already happened to be in the Balkans [they are deemed to be descendants of "Mesolithic" pastoralists, who came in from north Africa, and implicated by the E-M78* paragroup] when the Hg J bearing agriculture-innovators arrived, then picked up the agricultural traditions from these Hg J bearing agriculture "pioneers", and spread it thereof onto aboriginal European groups, like those including haplogroup I bearers.

In other words, one gets the impression from this article that the authors here are saying that Hg J-carrying populations were the ones largely responsible for introducing Neolithic farming culture into Europe, and that Hg E-carrying groups in Europe were the recipients, amongst others, albeit major agents of spreading it further deep into western Europe. If so, this runs counter to the generally acknowledged idea about the first "Near Eastern" farming communities being the product of the union between emigrant Hg E-bearing groups from mainland Africa and autochthonous "Near Eastern" groups. In other words, E-bearing groups were not recipients but co-agents of Neolithic farming introduction into Europe; this article however, gives an impression that suggests otherwise.

It isn't so much as what is "wrong with the theory" Battaglia et al. put forward, but rather, that it is inconsistent with the general consensus of Neolithic farmers arriving in with both Hg J and E carriers, together concurrently. While the SMGF article says that their indicators suggest that E-V13 emerged in the Balkans, Cruciani et al. on the other hand, who identified this marker and also tested E-M78 bearing groups, including sufficiently those in the Balkans, say that the star-like pattern of European clusters vs. the non-star-like pattern of the "Near Eastern" examples [including Anatolia] shows that while the marker reaches its frequency peak in the Balkans, it actually has relatively greater microsatellite diversity in the so-called Near East. This also suggests that V13 first emerged amongst late Mesolithic Anatolian/"Near Eastern" groups who brought and/or adopted the Neolithic farming culture from the Levant, but that it would eventually peak in frequency in southeastern Europe due to positive genetic drift and population expansions within that region. This too is inconsistent with what this new paper is telling us. The paper leaves one wondering about what specific loci examinations and phylogenetic reconstructions the authors base their claims on.

It is Cruciani's [the original identifier of the E-V13 marker] word against these authors about E-V13 emerging in the "Near East" rather than Europe, but peaking in frequency in the Balkans. Additionally, Cruciani et al. arrived at this, after having studied both Balkan and so-called Near Eastern samples. Cruciani et al.'s demonstration of E-V13 haplogroup structuring in Europe, along with their E-V13 haplogroup-structuring in the so-called Near East have been well documented with maps, supplemented by specified respective microsatellite information under study; the same remains to be deduced from the study at hand. Furthermore, the article says:

In addition, it is also worth noting the Anatolian region of supposed Einkorn wheat origin (region 5 of Cinnioglu et al.), only one V13 chromosome out of 43 is found (P. A Underhill unpublished data).

Whereas Cruciani et al. not only found a relatively higher frequency of V13 chromosome in their Anatolian sample, but also took into account the general Asian minor region. They also took into account V13 chromosomes in other "southwest Asian"/"Near Eastern" areas, not just select Turkish samples. Frequency here is not the issue, as both Cruciani et al. 2007 and the present authors agree on that point, about frequency peak being in the Balkans; however, within-region microsatellite diversity certainly is.

From the looks of it, the fact that the age estimation for a Turkish sample in the present study was relatively greater than those from Greek regions, is further cause to raise questions about the authors' thesis, in that they did not study the "Near Eastern" or "southwest Asian" area as extensively as they should have, an area where Cruciani & co. apparently seem to have done more. In fact, the present study's "Methods & Materials" section was examined, and therein, it doesn't appear that the authors even studied any "Near Eastern" populations themselves, other than select Turkish samples.

From personal communication elsewhere, opinion has been expressed that the present authors don't focus on the issue of whether or not haplogroup E carriers were amongst the Neolithic agriculture "pioneers" who initially introduced the economy into Europe; however, examination of the study at hand, suggests otherwise;

The paper does in fact address the issue of the "Neolithic pioneers", and what lineages were supposedly involved; see:

“To investigate the possible involvement of local people during the transition of agriculture in the Balkans, we analysed patterns of Y-chromosome diversity in 1206 subjects from 17 population samples, mainly from Southeast Europe. Evidence from three Y-chromosome lineages, I-M423, E-V13 and J-M241, make it possible to distinguish between Holocene Mesolithic forager and subsequent Neolithic range expansions from the eastern Sahara and the Near East, respectively. In particular, whereas the Balkan microsatellite variation associated to J-M241 correlates with the Neolithic period, those related to E-V13 and I-M423 Balkan Y chromosomes are consistent with a late Mesolithic time frame. In addition, the low frequency and variance associated to I-M423 and E-V13 in Anatolia and the Middle East, support an European Mesolithic origin of these two clades. Thus, these Balkan Mesolithic foragers with their own autochthonous genetic signatures, were destined to become the earliest to adopt farming, when it was subsequently introduced by a cadre of migrating farmers from the Near East.”

“The low E-V13 frequency and STR variation observed in Crete indicates tat if the first Neolithic colonists came from central Anatolia, they didn't bring this hg. The two more recent expansion times for V13 Greece and Sesklo and Dimini (Table 3), dating to the Bronze age, possibly reflect a more recent integration of some V13 chromosomes into populations of first farmers represented by J-M410 and G-M201 lineages.

Hgs G and J mark the successful colonization and subsequent demic expansions of Neolithic pioneers to these regions, consistent with a wave of advance, the widespread adoption of farming by Mesolithic hunter-gatherers in the Balkans and Central Europe is recorded in the autochthonous Hg I-M423.

These data indicate the complex interactions between farmers and foragers rather than the large-scale replacement of hunter-gatherers by pioneering agriculturalists during the spread from the Neolithic to the southeast Europe. The data also indicate that I-M423 and probably also E-V13 representatives would have been well established in the Balkans before the arrival of a nucleus of pioneering agriculturalists.

Thus, unlike Crete, southern and central Italy and the southern Caucasus, the cultural transmission of the Neolithic package played an important role. Either the initial G and J2 Hg agriculturalists who colonized the Balkans at first flourished but later diminished in a similar manner to that proposed regarding the Linearbandkeramik in central Europe or the package was rapidly and robustly adopted by local Mesolithic people in the southern Balkans (plausibly characterized by E-V13), who underwent a demic expansion and a subsequent range expansion to the eastern Adriatic. These former foragers who had recently acquired the Neolithic tradition participated in ‘leapfrog’ colonization up the Adriatic, where they eventually transmitted agriculture practices to resident Mesolithic populations represented by I-M423 chromosomes.”


In all the above pieces, "Neolithic pioneers of farming" are repetitively mentioned, implicating just Hgs G and J; the question then is, where has Hg E [or even E-M78*] been implicated in this group even once? However, E-M78* carriers have been implicated as being amongst the first supposed *converts* to the "Near Eastern-imported" Neolithic farming economy.

So, no, it isn't obvious that the authors here acknowledge Hg E-M78 carriers as part of the so-called "Neolithic pioneers" of the farming economy that spread into Europe. The challenge to those who see otherwise, is this question: Where do they make this obvious?

As a matter of classification [for the study], Cruciani et al. saw Balkans sans Asian Minor regions as part of Europe, just as these Battaglia et al. (the present authors) see them. To put it another way, Cruciani et al. don't include the Asian Minor as part of Europe, but rather, group them in the "Near Eastern" camp, as that region is generally treated in "Western" academia.

To reiterate, it appears that Battaglia didn't extensively study the so-called "Near Eastern" samples as Cruciani et al. did, aside from select Turkish samples. We don't even know how extensive Battaglia et al.'s Turkish samples were, which notwithstanding — from the little info they do provide, seems to corroborate Cruciani et al.'s position, that E-V13 chromosome's likely origins was somewhere in the Asian minor/Anatolia. This raises the question then: How is Battaglia et al. supposed to get a reasonably complete microsatellite phylogenetic pattern of the "Near East" vs. the Balkans, if they didn't extensively study the so-called Near East?

Lookout for ongoing updates, as they come to attention.

2 comments:

The Big Valley said...

quote:
In other words, one gets the impression from this article that the authors here are saying that J-carrying populations were the ones largely responsible for introducing Neolithic farming culture into Europe, and that Hg E-carrying groups in Europe were the recipients, amongst others, albeit major agents of spreading it further deep into western Europe.

Astute analysis as usual. Someone has to keep the academy honest. Based on avbailable evidence, would it not be just as likely that the "E" groups from the Eastern Sahara were part and parcel of the arrival/introduction of agriculture rather than solely the "J" migrants? It reminds me of alleged "Nubian slaves" claimed by assorted researchers when some dark-skinned type is shown in various Egyptian paintings, as if dark skin were somehow "foreign" to Egypt or confined to reputed "Nubians."

Mystery Solver said...

The Big Valley writes:

Based on avbailable evidence, would it not be just as likely that the "E" groups from the Eastern Sahara were part and parcel of the arrival/introduction of agriculture rather than solely the "J" migrants?

Indeed; it would.

The authors themselves don't exactly come out *loud* and say Hg E1b1b1a* (E3b*-M78) carriers were NOT [or vice versa] involved in the initial introduction of the Neolithic agricultural economy into Europe from the Levant, but by way of repetitive omission of said E3b groups from their invocations of Neolithic farming "pioneers", as they invoke Hg J [and in other instances, in companionship with Hg G, rather than said groups along with Hg E3b-M78 carriers] in the latter each time they mentioned them, they leave little doubt that they don't consider E3b carriers to be one of these "Neolithic farming pioneers".