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Three migrations were seen upon analysis of mtDNA  genomes of 14 ethnolinguistic groups.

Three migrations were seen upon analysis of mtDNA genomes of 14 ethnolinguistic groups.

The plot thickens!

It still fascinates me how regions of  the earth have been reached and populated by humans.  Particularly, I am curious how humans ‘conquered’ the islands of the Philippines. Curious because it says where I, a Filipino, and the rest of Filipinos came from.

I’ve written two blog posts about this topic already (here and here). Let me first summarize what I think are notable points in these studies. The first post is about the diversity of mtDNA in the Philippines by K. A. Tabbada et al [1]. In that paper, they said that the Philippines was populated mostly via Austronesian expansion (~5 000 years ago) but they found out that there is also an ancient lineage that links the Filipinos to people in Near Oceania and Australia (whose founder age they estimate to be ~47 000 years ago).  They point out that “there is evidence of substructuring within the lineages which means there is a pattern of long-term in situ evolution.”

The second post I wrote is about the human Y chromosome (NRY) diversity in the islands [2].  In that study, the authors obtained results similar to the mtDNA analysis such as the Austronesian expansion and a founder lineage. Moreover, they were able to connect different Filipino ethnolinguistic groups to different groups outside of the Philippines.  Three things are clear in that study: 1) there is genetic diversity even within Philippine populations (even within negrito groups), 2) there is no simple distinction between negrito and non-negrito groups, and 3) there are recent and ancient connections to the people of neighboring countries including Near Oceania and Australia.

Now, a recent paper in the European Journal of Human Genetics studied complete mtDNA of 14 ethnolinguistic groups in the Philippines [3]. They have found out that different groups posses different genetic make-up and that these different genetic make up is caused by different waves of migration that are both recent and ancient and an in situ diversification. These conclusions are similar to the first two papers but what I find striking are the reporting of a direct Indian migration to the islands and the suggestion that every ethnolinguistic group has unique genetic history.

The Indian-Philippine link is noteworthy. The presence of these haplogroups that connect the Filipinos and Indians have NOT been observed in other Southeast Asian groups. AetaZ and Agta groups which posses these haplogroups, “seem to demonstrate a direct mtDNA link between India and the Philippines.” How did the people from South Asia travel to the Philippines without passing through the rest of Southeast Asia? Maybe other regions in Southeast Asia are undersampled?

Another reason why it is remarkable is that it says that the timing of this migration to the islands is in between the initial colonization and the Austronesian expansion. The timing of migration also coincides with a similar migration of South Asians to Australia [4].

There is more to look forward to. The authors said, “although the NRY and mtDNA landscapes of the Filipino population are now described, these genetic systems are just two loci and specifically reflect respectively, male and female genetic histories. A more comprehensive view of Filipino diversity and history can still be sought through genome-wide variation.”

I will be waiting for your results eagerly!

Reference:
[1] K. Tabbada, J. Trejaut, J. Loo, Y. Chen, M. Lin, M. Mirazon-Lahr, T. Kivisild, and M. C. De Ungria,  Philippine Mitochondrial DNA Diversity: A Populated Viaduct between Taiwan and Indonesia? Mol. Biol. Evol. 27(1):21–31  (2010). DOI: 10.1093/molbev/msp215

[2]  Delfin F, Salvador JM, Calacal GC, Perdigon HB, Tabbada KA, Villamor LP, Halos SC, Gunnarsdóttir E, Myles S, Hughes DA, Xu S, Jin L, Lao O, Kayser M, Hurles ME, Stoneking M, & De Ungria MC (2010). The Y-chromosome landscape of the Philippines: extensive heterogeneity and varying genetic affinities of Negrito and non-Negrito groups. European journal of human genetics : EJHG PMID: 20877414

[3] Delfin F, Min-Shan Ko A, Li M, Gunnarsdóttir ED, Tabbada KA, Salvador JM, Calacal GC, Sagum MS, Datar FA, Padilla SG, De Ungria MC, & Stoneking M (2013). Complete mtDNA genomes of Filipino ethnolinguistic groups: a melting pot of recent and ancient lineages in the Asia-Pacific region. European journal of human genetics : EJHG PMID: 23756438

[4] Pugach I, Delfin F, Gunnarsdóttir E, Kayser M, & Stoneking M (2013). Genome-wide data substantiate Holocene gene flow from India to Australia. Proceedings of the National Academy of Sciences of the United States of America, 110 (5), 1803-8 PMID: 23319617

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