Geneticists have discovered that small populations representing the ancestral population of Melanesia (a chain of archipelagos in western Pacific, near northeastern Australia: New Guinea, New Caledonia, Vanuatu, Solomon Islands, Bismarck, and Fiji) possess one
of the highest genetic diversity amongst human populations.
This diversity was assessed investigating their mitochondrial DNA by a team led by Jonathan Friedlaender, emeritus professor of anthropology at Temple University, and was linked to where they live, the size of their home island and the language they speak.
The complex research included scientists from Binghamton University, the Institute for Medical research in New Guinea and the University of Pennsylvania, who examined genetic variety from 32 distinct populations on four Melanesian islands: Bougainville (from Solomon archipelago), New Britain and New Ireland (from Bismarck archipelago) and the big island of New Guiena. "Mitochondrial DNA has been a focus of analysis for about 15 years," says Friedlaender.
"It is very interesting in that it is strictly maternally inherited as a block of DNA, so it really allows for the construction of a very deep family tree on the maternal side as new mutations accumulate over the generations on ancestral genetic backgrounds. In this part of the world, the genealogy extends back more than 35,000 years, when Neanderthals still occupied Europe," he adds.
"These island groups were isolated at the edge of the human species range for an incredible length of time, not quite out in the middle of the Pacific, but beyond Australia and New Guinea. During this time they developed this pattern of DNA diversity that is really quite extraordinary, and includes many genetic variants that are unknown elsewhere, that can be tied to specific islands and even specific populations there. Others suggest very ancient links to Australian Aborigines and New Guinea highlanders."
This new research offers a different perspective on the "apparent distinctions between humans from different continents, often called racial differences. In this part of the Pacific, there are big differences between groups just from one island to the next - one might have to name five or six new races on this basis, if one were so inclined. Human racial distinctions don't amount to much."
Photo credit: Jonathan Friedlaender. Naturally blonde blacks from Malaita Island (Solomon)