Reduced mtDNA diversity in the Ngoebe Amerinds of Panama

Mitochondrial DNA (mtDNA) haplotype diversity was determined for 46 Ngoebe Amerinds sampled widely across their geographic range in western Panama. The Ngoebe data were compared with mtDNA control region I sequences from two additional Amerind groups located at the northern and southern extremes of Amerind distribution, the Nuu-Chah-Nulth of the Pacific Northwest and the Chilean Mapuche and from one Na-Dene group, the Haida of the Pacific Northwest. The Ngoebe exhibit the lowest mtDNA control region sequence diversity yet reported for an Amerind group. Moreover, they carry only two of the four Amerind founding lineages first described by Wallace and coworkers. We posit that the Ngoebe passed through a population bottleneck caused by ethnogenesis from a small founding population and/or European conquest and colonization. Dating of the Ngoebe population expansion using the Harpending et al. approach to the analysis of pairwise genetic differences indicates a Ngoebe expansion at roughly 6800 years before present (range: 1850-14,000 years before present), a date more consistent with a bottleneck at Chibcha ethnogenesis than a conquest-based event.