Philippine mtDNA, the Polynesian Motif, and Austronesian expansion

A new study (see below) examines mtDNA in the Philippines, Sulawesi and Taiwan.

The researchers study all the haplotypes tested but focus on the frequent mtDNA haplotypes B4a1a, E1a1a and M7c3c, which they claim support the "Out of Taiwan" model of migration.

Analysis of Hypervariable Segment I sequence variation within individual mtDNA haplogroups indicates a general decrease in the diversity of the most frequent types (B4a1a, E1a1a, M7c3c) from the Taiwanese aborigines to the Philippines and Sulawesi, although calculated standard error measures overlap for these populations.

However, as noted above with each finding the standard error for the comparisons overlapped, so the conclusions are not really meaningful.

What is interesting is the findings on the B4a1a haplotype and particularly those concerning its daughter haplotype B4a1a1, known commonly as the "Polynesian motif."

B4a1a1 is closely associated with Austronesian expansions, in my view specifically with Malayo-Polynesian expansion. While the parent haplotype B4a1a is frequent in Taiwan, the Philippines and Sulawesi, neither its predecessor B4a or the Polynesian motif B4a1a1 were found in the sample of 640 women from Taiwan.

The authors suggests that the Polynesian motif may have originated in the Philippines where it is present in small quantities in Mindanao. However they also conclude that because of the higher diversity of B4a1a in Taiwan that the haplotype must have migrated from there to the Philippines where it is found at the lower diversity. However, the estimated ages of 9,500 BP �4,600 for the haplotype in Taiwan and 7,900 BP �2,400 for the Philippines show an extensive overlap in the standard error calculation.

What seems more important is the presence of the parent B4a, which is present in small quantities in the Philippines but absent from Taiwan.

The estimated ages for the frequent haplogroups that the study focuses on i.e., 7300 BP for B4a1a, 7900 BP for E1a1a, and 11,400 BP for M7c3c, all seem to early to0 correspond to the commonly given dates for an Out of Taiwan expansion of Proto-Austronesian, which is generally place more in the range of 5000 BP.

Regards,
Paul Kekai Manansala
Sacramento
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Mol Biol Evol. 2009 Sep 15. [Epub ahead of print]

Philippine mitochondrial DNA diversity: a populated viaduct between Taiwan and Indonesia?

Tabbada KA, Trejaut J, Loo JH, Chen YM, Lin M, Miraz�n-Lahr M, Kivisild T, De Ungria MC.

DNA Analysis Laboratory, Natural Sciences Research Institute, Miranda Hall, University of the Philippines Diliman, Quezon City, Philippines.

Relatively little is known about the genetic diversity of the Philippine population, and this is an important gap in our understanding of Southeast Asian and Oceanic prehistory. Here we describe mtDNA variation in 423 Philippine samples and analyze them in the context of the genetic diversity of other Southeast Asian populations. The majority of Philippine mtDNA types are shared with Taiwanese aboriginal groups and belong to haplogroups of post-glacial and pre-Neolithic origin which have previously been identified in East Asian and Island Southeast Asian populations. Analysis of Hypervariable Segment I sequence variation within individual mtDNA haplogroups indicates a general decrease in the diversity of the most frequent types (B4a1a, E1a1a, M7c3c) from the Taiwanese aborigines to the Philippines and Sulawesi, although calculated standard error measures overlap for these populations. This finding, together with the geographical distribution of ancestral and derived haplotypes of the B4a1a sub-clade including the Polynesian Motif, is consistent with southward dispersal of these lineages "Out of Taiwan" via the Philippines to Near Oceania and Polynesia. In addition to the mtDNA components shared with Taiwanese aborigines, complete sequence analyses revealed a minority of lineages in the Philippines which share their origins - possibly dating back to the Paleolithic - with haplogroups from Indonesia and New Guinea. Other rare lineages in the Philippines have no closely related types yet identified elsewhere.

Two new studies on Austronesian expansion, peopling of Pacific

There are a couple of linked articles appearing in the latest edition of Science bearing on the peopling of the Pacific including the Austronesian expansion. I have not read the full articles yet, but have posted the abstracts below.

The first traces the a gut pathogen known as Helicobacter pylori suggesting that different Austronesian language branches are linked with related clades of this bacteria. The second study basically agrees with the first using this time linguistic phylogeny to trace the route of Austronesian speakers. Both studies claim that the Austronesian expansion began in Taiwan.

Opposing claims include an Austronesian expansion beginning in South China; and the two that I find most compatible with the evidence: an expansion from Indochina as espoused by Wilhelm Solheim; or from Sundaland or Insular Southeast Asia as brought forth by Stephen Oppenheimer. The datings also of the new study seem to recent when compared to the archaeological, genetic, and in my view also the linguistic evidence.

From other press releases, it appears that the authors are suggesting an initial expansion from Taiwan and then a secondary one from the Philippines. The second demographic movement might be linked with the divergence of Proto-Malayo-Polynesian, which if true I would find agreeable at least in terms of geography (but not chronology).

Regards,
Paul Kekai Manansala
Sacramento

Science. 2009 Jan 23;323(5913):527-530.

The Peopling of the Pacific from a Bacterial Perspective.

Moodley Y, Linz B, Yamaoka Y, Windsor HM, Breurec S, Wu JY, Maady A, Bernhöft S, Thiberge JM, Phuanukoonnon S, Jobb G, Siba P, Graham DY, Marshall BJ, Achtman M.

Max-Planck-Institut für Infektionsbiologie, Department of Molecular Biology, Charitéplatz 1, 10117 Berlin, Germany.

Two prehistoric migrations peopled the Pacific. One reached New Guinea and Australia, and a second, more recent, migration extended through Melanesia and from there to the Polynesian islands. These migrations were accompanied by two distinct populations of the specific human pathogen Helicobacter pylori, called hpSahul and hspMaori, respectively. hpSahul split from Asian populations of H. pylori 31,000 to 37,000 years ago, in concordance with archaeological history. The hpSahul populations in New Guinea and Australia have diverged sufficiently to indicate that they have remained isolated for the past 23,000 to 32,000 years. The second human expansion from Taiwan 5000 years ago dispersed one of several subgroups of the Austronesian language family along with one of several hspMaori clades into Melanesia and Polynesia, where both language and parasite have continued to diverge.

Science. 2009 Jan 23;323(5913):479-483.

Language Phylogenies Reveal Expansion Pulses and Pauses in Pacific Settlement.

Gray RD, Drummond AJ, Greenhill SJ.

Department of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.

Debates about human prehistory often center on the role that population expansions play in shaping biological and cultural diversity. Hypotheses on the origin of the Austronesian settlers of the Pacific are divided between a recent "pulse-pause" expansion from Taiwan and an older "slow-boat" diffusion from Wallacea. We used lexical data and Bayesian phylogenetic methods to construct a phylogeny of 400 languages. In agreement with the pulse-pause scenario, the language trees place the Austronesian origin in Taiwan approximately 5230 years ago and reveal a series of settlement pauses and expansion pulses linked to technological and social innovations. These results are robust to assumptions about the rooting and calibration of the trees and demonstrate the combined power of linguistic scholarship, database technologies, and computational phylogenetic methods for resolving questions about human prehistory.