May 08, 2012

Patrilineal signals of Austronesian expansion in mainland Southeast Asia

There was a recent paper on the spread of Austronesian in Island Southeast Asia, and now here's one on its spread in mainland Southeast Asia. Information about sampled populations can be found in Table 1. Haplogroup frequencies below:



PLoS ONE 7(5): e36437. doi:10.1371/journal.pone.0036437

Patrilineal Perspective on the Austronesian Diffusion in Mainland Southeast Asia

Jun-Dong He et al.

The Cham people are the major Austronesian speakers of Mainland Southeast Asia (MSEA) and the reconstruction of the Cham population history can provide insights into their diffusion. In this study, we analyzed non-recombining region of the Y chromosome markers of 177 unrelated males from four populations in MSEA, including 59 Cham, 76 Kinh, 25 Lao, and 17 Thai individuals. Incorporating published data from mitochondrial DNA (mtDNA), our results indicated that, in general, the Chams are an indigenous Southeast Asian population. The origin of the Cham people involves the genetic admixture of the Austronesian immigrants from Island Southeast Asia (ISEA) with the local populations in MSEA. Discordance between the overall patterns of Y chromosome and mtDNA in the Chams is evidenced by the presence of some Y chromosome lineages that prevail in South Asians. Our results suggest that male-mediated dispersals via the spread of religions and business trade might play an important role in shaping the patrilineal gene pool of the Cham people.

Link

6 comments:

Jim said...

This is interesting in and of itself, and when someone does the same thing for Daic (Thai and relatives)-speaking groups, that will be another piece of the picture. Daic languages look to be Austronesisan, branching at the same level as the languages in Taiwan. And of course it will be intersting when someone compares Cham and Daic populations with those Austronesian speakers on taiwan.

Jim said...

Oopsie. Looks like someone has done that.
http://dienekes.blogspot.com/2008/05/paternal-genetic-affinity-between.html

terryt said...

What I find most interesting is the complete absence of Y-DNA D in the sample. That argues against a 'coastal' migration for D. It is basically absent from regions accessible from the coast.

German Dziebel said...

@terry

Good point, Terry. I noticed it, too. It's also interesting that Cham and Kihn both have Y-DNA C3 plus a C*. The latter could be C2 or not but in any case, this suggests that C2 may not have been picked up by Austronesians before entering Polynesia, but in fact part of an original C2/C3 make up of Austronesians as a whole. This could be a sign of the "Mongoloid" component that they brought with them to Polynesia, and not a sign of an indigenous Papuan component that came in through admixture.

Same for mtDNA B4/B5: both lineages are present in both Chams and Kihns suggesting that B4 is not limited to Austronesians but in fact is a broader Southeast Asian component that Austronesians carried with them all the way to Polynesia.

South Central Haplo said...

O2 is strong in both islands and coastal mainland. A SNP analysis like done in other threads will help a lot in finding the genetic man/direction. O3 is more inland.

terryt said...

"It's also interesting that Cham and Kihn both have Y-DNA C3 plus a C*. The latter could be C2 or not but in any case"

It might not be C2 either. C* is claimed in Wikipedia as being found all round the South China Sea, while C2 is definitely Siouth Wallacean. C3's origin is very likely north of China. So the differentiation of C2, C4 and C3 considerably pre-dates the Austronesian expansion.

"this suggests that C2 may not have been picked up by Austronesians before entering Polynesia, but in fact part of an original C2/C3 make up of Austronesians as a whole".

As I just pointed out, it looks very much as if C2 and C3 origins are very much distant from each other. I would say that it is almost certain that C2 joined the Austronesians when they reached Southern Wallacea and, from there, moved almost entirely eastward into the wider Pacific.

"This could be a sign of the 'Mongoloid' component that they brought with them to Polynesia, and not a sign of an indigenous Papuan component that came in through admixture".

The Mongoloid element is far more likely to have been introduced by Y-dna O and mt-DNAs M7 and M9. C2 is moderately far from any early Mongoloid presence.

"Same for mtDNA B4/B5: both lineages are present in both Chams and Kihns suggesting that B4 is not limited to Austronesians but in fact is a broader Southeast Asian component that Austronesians carried with them all the way to Polynesia".

Very true. In fact B4'5 is part of haplogroup R11'B. The three mambers are spread around the South China Sea. R11'B6 in South China, R24 in the Philippines with B4'5 between these two opposite ends. The haplogroup's spread presumably goes back to the time of Sunda and lowered sea level.

"O2 is strong in both islands and coastal mainland".

I used to wonder if its spread was associated with the expansion of Austro-Asiatic languages. I'm drawing very near to concluding that it was.

"O3 is more inland".

Very much so. I doubt vwery much that it was associated with the early elements of the austronesian expansion but it has become the dominant O haplogroup in the Pacific.