Estimating the proportions of different ancestries in admixed populations is very important in population genetics studies, and it is particularly important for detecting population substructure effects in case-control association studies. In this work, a set of 48 ancestry-informative insertion-deletion polymorphisms (INDELs) were selected with the goal of efficiently measuring the proportions of three different ancestries (sub-Saharan African, European, and Native American) in mixed populations. All selected markers can be easily analyzed via multiplex PCR and detected with standard capillary electrophoresis. A total of 593 unrelated individuals representative of European, African, and Native American parental populations were typed, as were 380 individuals from three Brazilian populations with known admixture patterns. As expected, the interethnic admixture estimates show that individuals from southern Brazil present an almost exclusively European ancestry; Afro-descendant communities in the Amazon region, apart from the major African contribution, present some degree of admixture with Europeans and Native Americans; and a sample from Belém, in the northeastern Amazon, shows a significant contribution of the three ethnic groups, although with a greater European proportion. In summary, a panel of ancestry-informative INDELs was optimized and proven to be a valuable tool for estimating individual and global ancestry proportions in admixed populations. The ability to accurately infer interethnic admixtures highlights the usefulness of this marker set for assessing population substructure in association studies, particularly those conducted in Brazilian and other Latin American populations sharing trihybrid ancestry patterns.
A sample of 203 Brazilian males from Rio Grande do Sul (RS), the Brazilian southernmost state, was typed for 11 Y-STR markers (DYS19, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438, and DYS439). We also typed 42 individuals from two South Amerindian tribes (Kaingang and Guarani) to use the data as parental Amerindian contribution to our analyses. Gene and haplotypic diversities were estimated, with the South Amerindian samples showing smaller values for these parameters than Brazilians. To obtain a more comprehensive picture of the genetic structure of the Brazilian population as a whole, the Y-STR data from the RS sample was compared with those already published. No genetic substructuring was observed in the comparisons performed. Multidimensional scaling confirmed the proposed European source of most Y-chromosome Brazilian patrilineages.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.