DIFFICULTIES IN REJECTING A LOCAL ANCESTRY WITH mtDNA HAPLOGROUP DATA IN THE SOUTH-CENTRAL ANDES

This study assesses whether local genetic drift within populations can be rejected as a sufficient explanation for mitochondrial DNA haplogroup frequency changes between contemporary and prehistoric population samples in the South-Central Andes. Differences in the frequencies of haplogroups between populations are a popular line of evidence for assessing population history. The null hypothesis of haplogroup frequency change is a stochastic force inherent to finite populations called genetic drift. Genetic draft is particularly influential in small populations. Innumerable historical events can result in low population sizes. and the simplest scenarios for these events arc those occurring locally. In this study, simulations are used to provide a baseline for the amount of haplogroup-frequency difference expected from local genetic drift over time. The results from the simulations are compared to observed data front 23 population samples, including six prehistoric population samples. The study concludes that local genetic drift cannot he rejected when comparing a prehistoric population to a contemporary population. For the South-Central Andes, these results have dire consequences when attempting to infer genetic exchange. This study demonstrates that more informative genetic data are required for such inferences.