Polynesian ancestors may have migrated through RI: Research

Polynesian ancestors may have migrated through RI: Research

By Randolph E. Schmid

WASHINGTON (AP): The native peoples of the scattered
Polynesian islands in the vast eastern Pacific may have migrated
there via Southeast Asia and Indonesia, a new study indicates.

Previous research had suggested Polynesian origins were in
Taiwan or the southwestern Pacific islands of Melanesia.

But a new study led by Bing Su of the University of Texas
Health Science Center in Houston fails to support the older
theory, suggesting the South Asian migration route. The findings
are being published in Tuesday's issue of Proceedings of the
National Academy of Science.

The team studied the Y chromosomes of 551 men from across the
Pacific and Southeast Asia, comparing the distribution of 15
specific genetic markers on those chromosomes. The Y chromosome
is specific to males and is passed from father to son.

They found that the Taiwanese aboriginal peoples carried a
different set of these markers than either the Polynesians of the
eastern Pacific or the Micronesians of the northwestern Pacific.

Indeed, the study concluded that "the divergence between the
Taiwanese and the Micronesian/Polynesian populations is twice as
great as the divergence of either population group from Southeast
Asians."

The researchers concluded that the most likely explanation for
their findings is that both the original Taiwanese and the
Polynesians originated in Southeast Asia, but that they dispersed
independently of one another.

The researchers also noted that there has been controversy
over the extent to which the Melanesians of the southwestern
Pacific contributed to the populations of Micronesia, to their
north, and Polynesia, to their east.

They found one marker, H17, common in Melanesians was
completely missing in Polynesians, suggesting the Melanesian
contribution was "very low or negligible."

They also found no significant European contribution to
Polynesian ancestry.

While the Y chromosome study does not unequivocally point to a
center of origin for the Polynesians, the islands of Southeast
Asia, such as the Indonesian group, emerge as a probable
migration route, the researchers said.

The earlier theory of Polynesian origins, suggesting dispersal
via Taiwan, had been based on studies of mitochondrial DNA. That
is a type of DNA inherited only from the mother.

Some questions about the earlier studies have been raised in
recent years, but the researchers said the reason for the
different findings using the male-only Y chromosome is unclear.
One possibility, they suggested, might have been differences in
male and female migration patterns.

Polynesia is the group of Pacific Islands east of the
International Date Line, including Hawaii, Samoa, Tonga, the
Society Islands and others. Melanesia is generally south of the
Equator and west of the date line, including the islands from the
New Guinea to Fiji, the Solomon Islands and Vanuatu. Micronesia
is north of the Equator and west of the date line, including the
Mariana, Marshall and Caroline islands.

In addition to Bing Su, researchers taking part in the study
were from Fudan University, Shanghai, China; Stanford University,
Stanford, Calif., Nottingham University, Nottingham, England;
National University, Canberra, Australia; Brown University School
of Medicine, Providence, R.I.; Pennsylvania State University,
University Park, Pa.; Chinese Academy of Medical Science,
Kunming, and the University of Cincinnati in Ohio.