May 24, 2008

mtDNA and human dispersals in Southeast Asia

Yann Klimemtidis points me to this new paper. From the press release:
Prevailing theory suggests that the present-day populations of Island Southeast Asia (ISEA) originate largely from a Neolithic expansion from Taiwan driven by rice agriculture about 4,000 years ago - the so-called "Out of Taiwan" model.

However an international research team, led by the UK’s first Professor of Archaeogenetics, Martin Richards, has shown that a substantial fraction of their mitochondrial DNA lineages (inherited down the female line of descent), have been evolving within ISEA for a much longer period, possibly since modern humans arrived some 50,000 years ago.

Moreover, the lineage can be shown to have actually expanded in the opposite direction - into Taiwan - within the last 10,000 years.

Says Professor Richards: “I think the study results are going to be a big surprise for many archaeologists and linguists on whose studies conventional migration theories are based. These population expansions had nothing to do with agriculture, but were most likely to have been driven by climate change - in particular, global warming and the resulting sea-level rises at the end of the Ice Age between 15,000-7,000 years ago.”

Molecular Biology and Evolution 2008 25(6):1209-1218; doi:10.1093/molbev/msn068

Climate Change and Postglacial Human Dispersals in Southeast Asia

Pedro Soares et al.

Modern humans have been living in Island Southeast Asia (ISEA) for at least 50,000 years. Largely because of the influence of linguistic studies, however, which have a shallow time depth, the attention of archaeologists and geneticists has usually been focused on the last 6,000 years—in particular, on a proposed Neolithic dispersal from China and Taiwan. Here we use complete mitochondrial DNA (mtDNA) genome sequencing to spotlight some earlier processes that clearly had a major role in the demographic history of the region but have hitherto been unrecognized. We show that haplogroup E, an important component of mtDNA diversity in the region, evolved in situ over the last 35,000 years and expanded dramatically throughout ISEA around the beginning of the Holocene, at the time when the ancient continent of Sundaland was being broken up into the present-day archipelago by rising sea levels. It reached Taiwan and Near Oceania more recently, within the last ~8,000 years. This suggests that global warming and sea-level rises at the end of the Ice Age, 15,000–7,000 years ago, were the main forces shaping modern human diversity in the region.

Link

8 comments:

terryt said...

Maju. Have a look at my map 3 in the essay regarding MtEve! Exact fit.

We've known for more than forty years humans were in the Northern Solomons by 30,000 years ago so what's the surprise with this article? Journalistic hyperbole? And haplogroup E is not the one associated with people beyond the northern Solomon Islands so the article has no bearing on that region.

South Central Haplo said...

What are the ratios of mt haplogroups in SE Asia, any paper?

Majority of mt haplogroup in se Asia including E are derivatives of mt M.
Except in Australian aborigines where they have N.

Aborigines did not get help in expanding due to agriculture and M expanded due to agriculture etc in other areas.

Maju said...

Maju. Have a look at my map 3 in the essay regarding MtEve! Exact fit.


Hehe! But for this localized clade, which is perfectly within the coastal migration model anyhow.

I have not the slightest doubt that SE Asia was central for Eastern Eurasia and Oceania but I don't think this applies re. Western Eurasia (or even for the most part South Asia). That's one of the points we disagree at.

Majority of mt haplogroup in se Asia including E are derivatives of mt M.
Except in Australian aborigines where they have N.


What about B, F and R*? Agreed that B and F may have arrive from the north but not R* surely. Also P is not just found in Australia but in New Guinea as well.

terryt said...

The quote at the beginning of the article misrepresents the situation somewhat. The prevailing theory is not "that the present-day populations of Island Southeast Asia", but that the Austronesian languages, "originate largely from a Neolithic expansion from Taiwan driven by rice agriculture about 4,000 years ago". In 10,000 years languages would diversify far too much to see anything like a close relationship. So E's expansion is not connected to the Austronesian expansion. I'd suggest it probably has something to do with the Hoabinhian though.

Maju wrote: "P is not just found in Australia but in New Guinea as well". Now, the research quoted here tends to prove this haplogroup is part of a later movement across Wallace's line than the first one to New Guinea and Australia (N, giving rise to S). From the article: "haplogroup E ... evolved in situ over the last 35,000 years". In other words it hadn't even evolved when humans first reached Australia.

And I'd maintain that "global warming and sea-level rises" have always been "the main forces shaping modern human diversity in the region", not just "at the end of the Ice Age, 15,000–7,000 years ago".

Maju said...

In 10,000 years languages would diversify far too much to see anything like a close relationship.

Not necesarily. Think in Afroasiatic languages: they seem to have stemmed from Nubian Mesolithic, maybe the oldest grain-gathering economy in the world. Niger-Congo languages must also be quite old in their spread.

So E's expansion is not connected to the Austronesian expansion.

Maybe it's more connected with its prelude (Tai-Kadai/Austronesian divergence?). Not sure as the issue of Austronesian origins is somewhat controversial and it's not my primary area of interest anyhow.

Now, the research quoted here tends to prove this haplogroup is part of a later movement across Wallace's line than the first one to New Guinea and Australia (N, giving rise to S). From the article: "haplogroup E ... evolved in situ over the last 35,000 years". In other words it hadn't even evolved when humans first reached Australia.

How come? Aren't you reading too much into this excerpt?

If E has been evolving in situ, then Sahulian haplos too most likely. They have been separated for at least those 35,000 years (assuming the estimate is more or less correct), what is just slightly later than the archaeological dates of arrival of first humans to the area.

What the releases above are saying is that E has been evolving in Indonesia since the arrival of humans to the area (or some milennia later maybe). This basically excludes any movements from or towards mainland Oceania after that date.

Richard said...
This comment has been removed by the author.
Richard said...

Sorry, garbled that quote unforgivably

The paper contains this archaeological back-up, probably from David Bulbeck, who is a contributor:


These results open up a barely explored perspective on the population history of Homo sapiens in Southeast Asia.
They provide a window onto major, environmentally related demographic changes that took place before the proposed Neolithic/Austronesian dispersal that is usually the main point of reference for the prehistory of this region.
Moreover, archaeological evidence provides independent support for a large-scale dispersal across ISEA (or central/eastern Sundaland and Wallacea, as the region then was) during the 15,000 years after the LGM.
Prior to the LGM, there is no very clear distinction between the stone artifact assemblages of mainland Southeast Asia (MSEA—then, northwestern Sundaland) and ISEA.
However, following the LGM, 2 geographically discrete traditions or ‘‘technocomplexes’’ emerged. The Hoabinhian appeared across MSEA (including the Malay Peninsula) and the northern two-thirds of Sumatra. It was based on pebble tools flaked along their edges, usually on one face but occasionally bifacially (Solheim 1994; Bellwood 1997; Bulbeck 2003; Forestier 2007). In contrast, the ‘‘flake– blade technocomplex’’ was based on flakes detached from rotated multiplatform cores. This appears to have emerged as a distinctive stone tool technology approximately 25,000–30,000 years ago restricted to the islands and coastlines of the Sulu Sea region. After it had spread to northern Borneo ;18,000 years ago, it evidently dispersed throughout ISEA following the LGM (Bellwood 1997; Tanudirjo 2001; Mahirta 2003; Arifin 2004; Veth et al. 2005; Mijares 2006; Forestier 2007; Mijares 2007).
The expansion of the Hoabinhian from South China/Vietnam has already been related to the arrival of the R9b and N9a mtDNA haplogroups into the Malay Peninsula (Hill et al. 2006). Here, we now find a very close relationship between the geographic extent of post-LGM flake–blade industries and the haplogroup E lineages, again suggesting a close match between archaeological and genetic reconstructions.
Although Pleistocene assemblages assigned to the flake–blade technocomplex lack distinct stone tool types, post-LGM dispersal of Hoabinhian populations into ISEA,or flake–blade technocomplex populations into ISEA/Sumatra,would be expected to leave the mark of anomalous assemblages within their regional context—which are yet to be recorded archaeologically. The archaeology of Taiwan,however, does reveal the incursion of a distinct stone tool technology, which is particularly similar to North Luzon Holocene industries (cf., Mijares 2007). Although most Taiwan flaked stone industries of the last ;15,000 years are assigned to the Changpanian culture, which is related to the Hoabinhian (Bellwood 1997; Rolett et al. 2002),Zhang (2000) describes the appearance of a flake–blade industry,based on flakes struck from multiplatform cores, at 4 coastal sites in east Taiwan, all dated to 5,000–6,000 years ago. This would fit well with our estimated arrival from the south of E1a lineages in Taiwan.
Both the genetic and archaeological evidence therefore suggest that a maritime-oriented culture was in operation around the coastlines of what are now the Sulu and Sulawesi Seas by the LGM, which would have been preadapted to benefit from rising sea levels (Meacham 1984–1985; Oppenheimer 1998; Solheim 2006). The signature of dispersals from this region at the end of the Ice Age is evident both in the distribution of mtDNA haplogroup
E lineages and the expansion of the flake–blade technocomplex.

terryt said...

Hey thanks Richard. I'm pleased with myself. I wrote, "I'd suggest it probably has something to do with the Hoabinhian though". Mind you if you know a little of the prehistory of the region it's a pretty obvious connection.

And Maju. Although you say "it's not my primary area of interest" I maintain that what has happened in one region of the earth can give us insights into what's probably happened in at least most others.