MANILA, Philippines?This is what I remember from grade school: long, long ago, waves of people came and settled in the Philippines. One such group was composed of short, dark people. They moved farther inland, to high ground, when another wave of settlers, comparatively taller and fairer than the previous wave, came to the archipelago.

I?m sure there was more to the story we learned in class; a quick skim through the early Philippine history section of various texts indicates there may have been at least five waves of settlers in this archipelago. The texts also say some of these peoples came from the Malay Peninsula, but in last month?s issue of the journal Molecular Biology and Evolution, British researchers from the University of Leeds said that contrary to prevailing ?out of Taiwan? model, the people who settled in the Philippines, Malaysia and Indonesia in the last 5,000 years weren?t farmers from Taiwan.

Moved toward land masses

Based on genetic samples obtained throughout the region, the study authors said that people came from the islands of Southeast Asia and moved outward toward land masses including the Malay Peninsula, Taiwan and Papua New Guinea due to a series of floods caused by global warming.

?I think the study results are going to be a big surprise for many archaeologists and linguists whose studies conventional migration theories are based,? said study author and biologist Martin Richards. ?These population expansions had nothing to do with agriculture, but were most likely to have been driven by climate change.?

For the recently published study, the researchers analyzed the genetic information from 50 samples collected in Indonesia, Malaysia, Taiwan, Papua New Guinea and the Philippines?including one sample each from Batanes, Luzon, the Visayas and Mindanao. The researchers studied the mitochondrial DNA, the genetic information passed down from mother to child, and traced the spread of certain genes over time.

According to the researchers? genetic analysis, a good portion of the Philippines was settled about 7,000 years ago, likely during one of the final major flooding events post-Ice Age. The small pool of genetic samples used for the study is only 15 percent of the total genetic diversity in the region, the authors noted, but they added that preliminary results suggest the analysis would also hold if more samples are collected and studied.

Described in the university press release as ?the UK?s first professor of archeogenetics,? Richards looks at how humans? genetic sequences vary from each other by correlating the biology with the anthropological and historical records for the area. In recent years, he?s traced the route early humans used to move out of Africa, and when and how they spread out over Europe.

Prehistorical settlement

Lately though, Richards and his colleagues from various international institutions have focused on the prehistorical settlement of Southeast Asia. In the research article, they described how Southeast Asia looked about 50,000 years ago this way: The Malay peninsula, which includes Thailand, Malaysia and Singapore, was part of a larger land mass called ?Sundaland,? which linked the peninsula to the islands of Sumatra and Borneo.

About 20,000 years ago, the most recent Ice Age ended, and the resulting climate change caused a series of floods over the next few millenniums, increasing the coastlines even as whole portions of land and settlements disappeared under ever-higher sea levels. With more lands opening up and fewer people claiming these areas, the early humans spread out and built settlements.

The study may not significantly change my view on the nation?s prehistory, but it does provide food for thought on the relationship between migration and effects of long-term global warming.

E-mail the author at massie@massie.com.