Y Chromosome Study Reveals Details on Timing of Human Settlement in Americas

An analysis of Y chromosome sequences from a haplogroup representing virtually all Native American lineages in Mesoamerica and South America is presented in PLOS One this week, offering new details about the timing of human settlements in the region. In the study, a team led by scientists from the Universidad Nacional de La Plata analyzed the Pan-american Y chromosome Q Haplogroup, building a phylogenetic tree using new whole Y chromosome sequences from 13 Argentine samples and sequences from 89 published samples. With the data, the researchers uncover evidence for a South American settlement before 18,000 years ago and the substantial loss of linages during a rapid environmental cooling event in the Northern Hemisphere known as the Younger Dryas. Further investigation is required to better understand the first South American settlements, the study's authors write, including ones with a larger number of diverse individuals with Native American ancestry and a larger number of sequences belonging to ancient Native American sublineages. Future efforts should also focus on the causes behind the environmental changes triggered during Younger Dryas.