Category: Migrations


Based on archaeology, linguistics, and, most recently, genetics, it is traditionally thought that Polynesia was inhabited by mariners originating in Taiwan or south China beginning about 3,500 years ago (in fact, our departmental reading, Relethford’s “Reflections of Our Past,” has an interesting chapter on this issue).

Polynesia is made up of hundreds of islands. Figure from acmecompany.com

A recently published study modifies this story somewhat. This study looked at the largest mtDNA (which is only passed through the maternal line) sample to date in order to determine which populations were most similar to modern Polynesians. From an interview with Martin Richards, one of the members of the research team, in the ScienceDaily summary:

“Most previous studies looked at a small piece of mtDNA, but for this research we studied 157 complete mitochondrial genomes in addition to smaller samples from over 4,750 people from across Southeast Asia and Polynesia. We also reworked our dating techniques to significantly reduce the margin of error. This means we can be confident that the Polynesian population — at least on the female side — came from people who arrived in the Bismarck Archipelago of Papua New Guinea thousands of years before the supposed migration from Taiwan took place.”

 What is especially interesting here is that the linguistic and archaeological evidence still strongly suggest some sort of connection with Taiwan. For one, modern Polynesian languages are thought to belong to the Austronesian language family, which is a group of languages spoken from Madagascar to Easter Island, but differ from the native languages of Australia and New Guinea. Archaeologists maintain that the earliest Polynesian pottery (called the “Lapita Culture”) shares many similarities to earlier pottery found on Taiwan and in south China. So, how do we reconcile these findings with the genetics? Again, Dr. Richards:

“Although our results throw out the likelihood of any maternal ancestry in Taiwan for the Polynesians, they don’t preclude the possibility of a Taiwanese linguistic or cultural influence on the Bismarck Archipelago at that time,” explains Professor Richards. “In fact, some minor mitochondrial lineages back up this idea. It seems likely there was a ‘voyaging corridor’ between the islands of Southeast Asia and the Bismarck Archipelago carrying maritime traders who brought their language and artefacts and perhaps helped to create the impetus for the migration into the Pacific.

“Our study of the mtDNA evidence shows the interactions between the islands of Southeast Asia and the Pacific was far more complex than previous accounts tended to suggest and it paves the way for new theories of the spread of Austronesian languages.”

This implies that later populations were moving through the area with their language and culture, but they were not necessarily bringing their genes (i.e., interbreeding), at least on the female side.

References

Soares, P., et al. Ancient Voyaging and Polynesian Origins. American Journal of Human Genetics 88: 239-247.

For those of you who don’t know, all students in UNCG’s 300+ level anthropology courses are reading a book and several articles in preparation for the Harriet-Elliott events. One of these readings, John Relethford’s “Reflections of Our Past,” has a chapter on the peopling of the Americas. Traditionally, most scholars contend that the first humans entered the Americas about 15,000 years ago (or maybe a bit earlier) and came from Asia via the Bering Land Bridge that then existed between modern-day Alaska and eastern Siberia.

Possible migration routes for the first colonization of the Americas

According to Relethford, who was writing in 2003, the genetics strongly supports an origin of Native Americans somewhere in Asia:

1. Contemporary Native Americans and northern Asians tend to have high frequencies of the Diego blood group allele DI*A (this allele is relatively rare among other populations).

2. Based on genetic distance analysis (which takes into account the relative frequency of many different genes simultaneously to look at overall genetic difference/similarity), contemporary northeast Asian populations are most genetically similar to Native Americans.

3. Native Americans share a number of mitochondrial DNA haplotypes (sections of DNA that are inherited together as a single unit) with Asian populations (some from Siberia, some from Japan and Korea).

Relethford also discusses another interesting question: how many migrations occurred? Was it a single migration event? Two? Three? More? The genetic data seem to suggest at least two separate migration events, if not more.

Finally, when did the first colonization of the Americas take place? Here, Relethford shows that the genetic data are pretty cloudy because any estimate based on a genetic clock will be affected by population size and the overprinting of multiple migrations. Indeed, Relethford suspects that “the final determination of the age of the first Americans will be settled by archaeology and not by genetics.”