December 21, 2010

Y-chromosomes and mtDNA from Maharashtra

The paper has a nice map of the frequency of haplogroup J2a-M410, which is an update of the previous map from Sengupta et al. (2006)

The most recent gene flow paternal gene flow from West Asia corresponds largely to this haplogroup.

Unfortunately the authors used the "evolutionary mutation rate" which I and others have criticized, hence their age estimates are inflated. J2a and R1a1 have similar Y-STR variances in the two studied populations (0.36 and 0.34), and their ages are roughly a third of those reported (with wide uncertainty), or about ~4ky.

This is roughly consistent with the postulated arrival of the Indo-Aryans in India, and should probably be added to the enumeration of cases where the genealogical mutation rate correlates well with prehistory. It also seems consistent with my speculation about a West Asian origin of the Indo-Aryans.

Haplogroup R1a1 is more diverse in India-Pakistan than in west Eurasia, but there is variation in diversity in different South Asian groups. It's possible that a subgroup of it also migrated from the west, but that possibility must remain speculative in the absence of even more Y-SNP structure within it. Interestingly:
The network analysis of R1a with other Indian populations failed to provide any regional or linguistic clustering (Fig. S2).

The new Y-chromosome data from this paper can be found in Table S2.

PLoS ONE 5(12): e15283. doi:10.1371/journal.pone.0015283

The Influence of Natural Barriers in Shaping the Genetic Structure of Maharashtra Populations

Kumarasamy Thangaraj et al.

The geographical position of Maharashtra state makes it rather essential to study the dispersal of modern humans in South Asia. Several hypotheses have been proposed to explain the cultural, linguistic and geographical affinity of the populations living in Maharashtra state with other South Asian populations. The genetic origin of populations living in this state is poorly understood and hitherto been described at low molecular resolution level.

Methodology/Principal Findings
To address this issue, we have analyzed the mitochondrial DNA (mtDNA) of 185 individuals and NRY (non-recombining region of Y chromosome) of 98 individuals belonging to two major tribal populations of Maharashtra, and compared their molecular variations with that of 54 South Asian contemporary populations of adjacent states. Inter and intra population comparisons reveal that the maternal gene pool of Maharashtra state populations is composed of mainly South Asian haplogroups with traces of east and west Eurasian haplogroups, while the paternal haplogroups comprise the South Asian as well as signature of near eastern specific haplogroup J2a.

Our analysis suggests that Indian populations, including Maharashtra state, are largely derived from Paleolithic ancient settlers; however, a more recent (~10 Ky older) detectable paternal gene flow from west Asia is well reflected in the present study. These findings reveal movement of populations to Maharashtra through the western coast rather than mainland where Western Ghats-Vindhya Mountains and Narmada-Tapti rivers might have acted as a natural barrier. Comparing the Maharastrian populations with other South Asian populations reveals that they have a closer affinity with the South Indian than with the Central Indian populations.



German Dziebel said...

I assume you equate J2a with your autosomal Daghestani component and date both at some 4,000 years BP. Is this the date you suggest for the Indo-Aryan branch of Indo-European? What's, IYO, the age of Indo-European as a whole?

Gioiello said...

I think it is clear from this paper that the haplogroup of the agriculturalists who expanded from Anatolia/Caucasus was J2 and not R1b1b2. If it was like that, we would have to have the same figure of it like J2 and it isn't so. R1b1b2 either arrived from East if Vizachero and the others are right about its ancientness or from West (Italy, Spain?) if its ancientness is older as I think.

Andrew Lancaster said...

I think it is clear from this paper that the haplogroup of the agriculturalists who expanded from Anatolia/Caucasus was J2 and not R1b1b2. If it was like that, we would have to have the same figure of it like J2 and it isn't so.

No this does not follow at all. If there are major expansions to a large group of areas from a smaller area there is absolutely no reason to think that all the newly colonized areas will end up with the same selection of male lines dominating them, even if each of the colonized regions will show a domination.

velvetgunther said...

If, as you say, this is Indo-Aryan or Indo-Iranian then that would somewhat fit with Colin Renfrew's Anatolian origin hypothesis. However, it's surprising to see greater concentrations in west and south west India rather than in the northern states of Punjab and UP, which were the centres of Indo-Aryan culture.

Jack said...

The idea I have is that indo-iranian/aryan entered the heart of the ME from the north or east preceded by other languages such as hurrian urartian. Maybe due to a population expansion north of the Caucasus. Hence Mitanni.
I think this J2 is tied to agriculture.

terryt said...

"I think this J2 is tied to agriculture".

So do I. I suspect it entered India long before the Indo-European speaking people did. Therefore J2 is not an IE marker. The fact it survived in the priestly classes after the IEs came in is no surprise. Invaders often leave the previous administrative class to run things while they live the high life. This would account for:

"However, it's surprising to see greater concentrations in west and south west India rather than in the northern states of Punjab and UP, which were the centres of Indo-Aryan culture".

The centres of Indo-Aryan culture are exactly where we'd expect the greatest loss of pre-IE male haplogroups.

ashraf said...

If J2 would have been entering with agriculture one will expect to see a distribution patern of J2 very similar to that of neolithic introduced R1b, but that's NOT the case.
J2 distribution patern fits VERY WELL with a recent bronze age dated diffusion into Europe and India-Iran (since the frequency of J2 decreases as long as we go away from the J2 epicenter in Anatolia-Western Iran)
R1a distribution patern in India-Eastern Europe is very likely a result of mesolitihic human movement, while R1b distribution patern in Europe is very likely associated with the repopulation of Europe from Anatolia after LGM.
Anyway both R1a and R1b distribution paterns are AGAINST the philogenetic connection of IE branches and the FACTS that Proto Indo-European desintegration is very recent (3000-2000 bc) as well as against the internal paradigmas of Proto Indo-European such as the Semitic,Egyptian and Sumerian...loanwords+fauna,technology,metallurgy,mythology and flaura of PIE points to a western Asian origin.
Surely R1a and R1b distribution paterns show very ancient human migrations and thus CANNOT BE ASSOCIATED with ancient indo-european languages speakers' expansion.
J2 distribution patern fits very well with a bronze age dated expansion (wich of course would not result in J2 being the major hg of Europe and India as major hg's in those 2 areas should have came by very ancient mesolithic and neolitihic times) and there was a consequent and duratorly continuing process of language shift with european IE languages being the result of symbiosis between locals non IE (who gave their phonetics and many cultural words to the newborn dialects) and newcomer IE speakers, the fact that only Anatolic and Armenic ,laying very close to the PIE homeland, have retained (only 1out of the 3 larynegeal for Armenian though) all the 3 PIE larynegeals while lost in all other IE dialects as well as the fact that Indic phonology (with its peculiar retroflexes) is a local India pre IE one, is very suggestive!

Jack said...

Loanwords are just I keep an open mind, but if we are talking about 2000 BC I still opt for a central eastern european expansion for centum languages and steppes for satem. I wonder how accurate this J2 map is, but there is a concave dip in the northern balkans isolines. Of course this does not mean that IE people did not have J2 from more ancient times maybe via other people and in some areas especially.
Actually, I find interesting the possibility that IE languages were in europe long before.
Speculating: what if Pre-proto IE was in Italy for example. Maybe after some deicing it moved north.
Perhaps tHis could combine somehow with J2.
But I suspect it would have been there before neolithic.
This version would also make Gioiello happy from what I understand.

Gioiello said...

Of course I am happy, but not when my postings are stopped.
Anyway my analysis is on R1b1b2 haplogroup, and I think having demonstrated that it was in Italy at least till R-L51. I don't know if they spoke IE languages. I have said something different, that the original languages of Italy (Rhaetian-Etruscan-Camun) could have been linked with what became after IE languages. But IE languages can have come from East recently: it is clear that they had some links with Ugro-Finnic languages. What it is important for me is that R1b1b2, and above all its subclades, come from Western Europe, perhaps from Italy.

ashraf said...

"Loanwords are just"

Loanwords also serve to establish the spatial and temporal homeland and migration path of each ancestral proto language.
For example grace of old Chinese, Nenets, Yeniseyan and Yukaghir loanwords into proto Turkic we could determine that proto Turkic developped somewhere around Lena river in northeastern Siberia and can not be dated earlier than 500 BC with its date of desintegration(because of migrations)something around 0 CE.
Semitic+Egyptian+Sumerian+Kartvelian loanwords into proto Indo-European are clues for eastern Anatolian origin for PIE.