Meta-analysis of Brazilian genetic admixture and comparison with other Latin America countries.

Abstract

This study aims at performing a systematic review and meta-analysis with the studies of genetic admixture inference of Brazilian population and to compare these results with the genetic admixture levels in other Latin American countries. We searched for articles regarding the estimation of Brazilian genetic admixture published between 1980 and 2014 that used autosomal markers. Then, conducted meta-analyses at the whole-country and regional level. Finally, we compared the results of Brazil with other estimates from other South, Central and North American countries. We analyzed data from 25 studies in 38 different Brazilian populations. European (EUR) ancestry is the major contributor to the genetic background of Brazilians, followed by African (AFR), and Amerindian (AMR) ancestries. The pooled ancestry contributions were 0.62 EUR, 0.21 AFR, and 0.17AMR. The Southern region had a greater EUR contribution (0.77) than other regions. Individuals from the Northeast (NE) region had the highest AFR contribution (0.27) whereas individuals from the North regions had more AMR contribution (0.32). In the Latin America context, Brazil has the 5th high EUR contribution, the 12th for the AFR component and the 10th for the AMR ancestry. Admixture proportions vary greatly among Brazilian populations and also through Latin America. More studies in the Center-West, North and NE regions are needed to capture a more complete picture of the genomic ancestry of Brazil.