EVIDENCE OF MITOCHONDRIAL-DNA DIVERSITY IN SOUTH-AMERICAN ABORIGINALS

The absence in South American aboriginals of an Asian-specific marker, a 9-bp deletion between the genes for the second subunit of cytochrom e oxidase II and lysine transfer RNA in region V, has been interpreted as a bottlenecking effect at the Isthmus of Panama during the peoplin g: of the Americas. We screened mitochondrial DNA (mtDNA) for this 9-b p tandem repeat and for polymorphisms in specific regions of the mtDNA in 2 ancient and 31 contemporary samples from South American aborigin als. We found additional (mtDNA) diversity in South American aborigina ls in three ways. First, an Asian-specific marker not previously repor ted in South American aboriginals was identified by a sequencing analy sis in both the contemporary Andean and Amazonian aboriginal peoples. Second, two new haplotypes so far unique to South American aboriginals were found. Additionally, we show that South American aboriginals fal l into discrete populations. These results suggest that the prehistori c colonization of South America is the outcome of multiple migrations; the data do not support a bottlenecking effect at the Isthmus of Pana ma.