July 22, 2006

mtDNA and human movements in Oceania

Definitions of Remote Oceania and Near Oceania.

Mol Biol Evol. 2006 Jul 19; [Epub ahead of print]

Deciphering Past Human Population Movements in Oceania: Provably Optimal Trees of 127 mtDNA Genomes.

Pierson MJ, Martinez-Arias R, Holland BR, Gemmell NJ, Hurles ME, Penny D.

The settlement of the many island groups of Remote Oceania occurred relatively late in prehistory, beginning ca. 3000 years ago when people sailed eastwards into the Pacific from Near Oceania where evidence of human settlement dates from as early as 40 000 years ago. Archaeological and linguistic analyses have suggested the settlers of Remote Oceania had ancestry in Taiwan, as descendants of a proposed Neolithic expansion that began ca. 5500 years ago. Other researchers have suggested that the settlers were descendants of peoples from Island Southeast Asia, or the existing inhabitants of Near Oceania alone. To explore patterns of maternal descent in Oceania we have assembled and analyzed a dataset of 137 mtDNA genomes from Oceania, Australia, Island Southeast Asia and Taiwan that includes 19 sequences generated for this project. Using the MinMax Squeeze Approach (MMS) we report the consensus network of 165 most parsimonious trees for the Oceanic dataset, increasing by many orders of magnitude the numbers of trees for which a provable minimal solution has been found. The new mtDNA sequences highlight the limitations of partial sequencing for assigning sequences to haplogroups and dating recent divergence events. The provably optimal trees found for the entire mtDNA sequences using the MMS method provide a reliable and robust framework for the interpretation of evolutionary relationships and confirm the female settlers of Remote Oceania were descended from both the existing inhabitants of Near Oceania and more recent migrants into the region.

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