Expansion of E-V13 and I-M423 from the Balkans

The most interesting aspect of this paper is that it supports a European rather than Middle Eastern origin of E-V13 and I-M243 based on an analysis of relative Y-STR variance. However, the age estimates presented in this paper are based on the infamous "evolutionary mutation rate", and are thus suspect. What appears as "Mesolithic" using the wrong mutation rate is actually Bronze Age, although with hefty confidence intervals.

Furthermore, caution should be used when correlating TMRCA with archaeological events. As I have noted before, the founder of a haplogroup is not the same as the Most Recent Common Ancestor (MRCA) of the present-day population from that haplogroup. This study seems to argue against the Middle Eastern origin of E-V13 suggested by Cruciani et al..

When exactly E-V13 came to the Balkans remains to be seen, but its expansion is properly placed in a Bronze Age rather than Mesolithic time frame. Interestingly, the paper has turned up some additional evidence:

Only four E-M78*, which do not belong to any already described sub-clade, have been observed in the southern Balkans. Two of them (from Greece) turned out to be characterized by the mutation M521 and therefore represent a new M78 lineage.

...

The presence of E-M78^* Y chromosomes in the Balkans (two Albanians), previously described virtually only in northeast Africa, upper Nile, gives rise to the question of what the original source of the E-M78 may have been.

This is suggestive that E-V13 expanded from the Balkans out of a pre-existing E-M78 ancestor, almost completely swamping that E-M78 population. When exactly E-M78 arrived in the Balkans, it is difficult to say, since Y-STR variance takes us only as far back as the MRCA who lived in the Bronze Age.

In any case, this paper adds important new data on Balkan Y-chromosomes, although it is unfortunately marred by facile Y-chromosome/archaeological correlations, and the use of the inappropriate evolutionary mutation rate.

At present, I see no reason to change my theory on the expansion of E-V13. The finding that E-V13 is less diverse in Anatolia and the Middle East further reinforces the idea of the Balkan origin of that expansion, while an estimated age in the 2nd millennium BC is consistent with the birth of the Greek world.

The authors write:

Interestingly, J-DYS445-6 and J-M92 (a sub-lineage of M67), both have expansion times between 7000 and 8000 years ago

Converted into non-"evolutionary" ages, these are again consistent with the expansion of the Greek world. J-M92 was correctly associated with the expansion of the Greek world by Di Giacomo et al. (2004) "Y chromosomal haplogroup J as a signature of the post-neolithic colonization of Europe", who did not fall into the evolutionary mutation rate trap.

Also of interest is the discovery of an extremely rare R1a*(xR1a1) in a single Macedonian Greek. Another instance of R1a*(xR1a1) was previously discovered in a Cretan Greek. R1a1 occurred in 16.3% of Greeks from Athens vs. 10.5% of Greeks from Macedonia, the opposite of what was observed by Semino et al. in 2000. R1a1 does not seem to have any clear geographical structure within Greece, which would be expected if it was of more recent introduction.

UPDATE: Having labeled E-V13 Mesolithic, the authors label haplogroups G and J2 as Neolithic. A most interesting observation (Table 1) is that haplogroup J2a-M410* and J2b-M12* have the maximum and second maximum Y-STR variance in the region, being much more diverse than other haplogroups supposedly representing pre-agricultural Europeans.

At least, such a finding should give pause to those who arrive at facile conclusions about ages of human migrations on the basis of Y-STR variance.

European Journal of Human Genetics doi:10.1038/ejhg.2008.249

Y-chromosomal evidence of the cultural diffusion of agriculture in southeast Europe

Vincenza Battaglia et al.

Abstract

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.

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