DNA Research on Polynesian Origins and Migrations

[Illustration: DNA strand]

We carry our histories within us, in our genes and in our DNA.  New techniques of DNA analysis are now allowing researchers to learn more about human history, including the migration paths of the ancient Polynesians who sailed their double-hulled voyaging canoes over the largest ocean in the world to become the first Hawaiians. 

It has long been a question of science exactly how and when Earth’s continents and islands were first inhabited by humans.  An ancient proverb referring to the Hawaiian’s ancestors states, “I ulu no ka lālā i ke kumu” (“The branches grow because of the trunk”).[i]

Scientists have traditionally relied on fossils and linguistic similarities to trace back through time and discover the history of ancient humans.  This research has been revolutionized by recent studies[ii] on strands of hair and human cells containing the DNA that reveals to scientists clues about our distant past.

DNA studies are also pinpointing the very earliest of human origins.  One recent study of a complete human genome concluded that humans first migrated out of Africa into Europe and Asia about 52,000 years ago. 

Genetic analyses have also led to new discoveries in the fields of anthropology, archaeology, and paleontology, supplementing traditional evidence such as fossils, artifacts, and site excavations.

[Illustration: Human migration graphic]

A study led by Dr. Geoffrey Chambers of Victoria University concluded that the ancestors of Polynesian people first migrated from Taiwan and China to the Philippines and Indonesia, then to West Polynesia and East Polynesia, and then to New Zealand.   Chambers analyzed DNA data that had originally been collected for a study on genetics and alcoholism.

The DNA profiles in Chamber’s study showed that there is less genetic diversity in Polynesians than in other groups.  For example, the probability of finding two individuals with the same DNA profile is 1 in 112 million for Asians, and 1 in 47 million for Caucasians, but only 1 in 6.7 million for Polynesians. 

Researchers theorize that these lower rates of genetic diversity are a result of the fact that Polynesians, sailing voyaging canoes to inhabit remote Pacific islands were very isolated from other races.  There are more than 20,000 islands throughout the Pacific Ocean, which is 25% larger than all the world’s land combined.  The Polynesians settled many of these distant and isolated islands.

Mitochondrial DNA—Three Main Subgroups of Polynesians

Another recent genetics project was led by University of Hawai‘i scientist Rebecca Cann.  Cann’s study analyzed mitochondrial DNA, unlike the Victoria University study, which used nuclear DNA.  Mitochondrial DNA is inherited only from the mother.

Analyzing hair samples gathered from people all around the Pacific, the researchers concluded that there are three main subgroups of Polynesians.  The study found that 95% of all Hawaiians are in one of these three sub-groups, along with 90% of Sāmoans and all the Tongans sampled.  Interestingly, this genetic marker that distinguished the Polynesian sub-groups was also found in some Native Americans. 

A second genetically distinct sub-group of Polynesians contains a small minority of Hawaiian people as well as people from Sāmoa and the Cook Islands.  A third group doesn’t seem to show up at all in the Hawaiian Islands, but appears to link Sāmoans to Indonesians.  Cann’s research also concluded that it is likely that Polynesians first sailed to South America, rather than the other way around, as many researchers had previously asserted. 

Cann’s genetic study traces the Polynesian expansion from the Southeast Asia mainland to some time around 6,000 years ago.  Cann theorizes that there were several waves of migrations from Asia, and that Micronesia was settled after Polynesia, contrary to what most anthropologists have claimed.

Y Chromosomes Study

A research project at the University of Texas Health Science Center studied the Y chromosomes of 551 men from Southeast Asia and the Pacific.  The Y chromosome is passed only from fathers to sons, and so it is specific to males (unlike the mitochondrial DNA in the previous study).  This University of Texas research found that aboriginal Taiwanese carried distinctly different genetic markers than eastern Pacific Polynesians or southwestern Pacific Micronesians. 

The Texas study also found that the Micronesians/Polynesians were more closely related to Southeast Asians than Taiwanese.  These findings cast doubt on the previous reigning theory that Taiwan was the ancestral origin of Polynesians.  The history of Polynesian migration will become clearer as new genetic analysis techniques are refined.

Origins of the First Hawaiians

Before DNA research began yielding new clues to Polynesian origins, information about the first Hawaiian settlers came predominantly from archaeological and linguistic evidence.  The oldest evidence from Hawaiian archeological sites links the Hawaiian Islands to the Marquesas Islands, an archipelago about 2,500 miles (4,020 km) southeast of the Hawaiian Islands. 

Fish hooks found in both places are also remarkably similar, including the particular notching of the shank of the hook.  Research has also shown that the language of the ancient Hawaiians is more closely linked to the Marquesan language than to any other Polynesian language or dialect. 

The same DNA techniques that genetic anthropologists are using to discover ancient family lineages of Hawaiians are being used to study the spread of diseases among endangered Hawaiian bird species.  Another application of DNA studies helps scientists with the captive breeding of endangered Hawaiian birds, including the native honeycreepers. 

[Photograph: Endemic Hawaiian bird]