Admixture in Latin America: Geographic Structure, Phenotypic Diversity and Self-Perception of Ancestry Based on 7,342 Individuals

TLDR

Latin America’s current genetic makeup results from extensive admixture among Africans, Europeans, and Native Americans within a context of geographic and social stratification. The study estimated individual ancestry proportions for 7,342 participants from Brazil, Chile, Colombia, Mexico, and Peru, and characterized them for physical appearance traits and self‑perceived ancestry. The geographic distribution of admixture proportions reveals extensive population structure, and ancestry has significant but modest effects on most phenotypes, with genetically estimated and self‑perceived ancestry correlating yet certain physical attributes bias self‑perception relative to genetic estimates.

Abstract

The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry.