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A revertant of major founder Native American haplogroup C common in populations from Northern South America is studied. Genetic structure analyses are consistent with the reversion mutation occurring at an early stage during the tribalization process.

One hundred nineteen individuals classified as White, living in different localities of the Brazilian state of Rio Grande do Sul, were studied in relation to the HVS-I region of the mitochondrial DNA. The results indicate that Brazilian populations are remarkably heterogeneous, while some present an overwhelming majority of transplanted European genomes.

A history of symmetrical and asymmetrical matings has been developed according to sex as revealed by bi- and uni-parental genetic markers in South American populations of predominantly African derivation. Eleven such populations were studied for estimates of African, European and Amerindian contributions to each gene pool. Five autosomal loci and one Y chromosome hypervariable locus were used along with mtDNA. Thirty-eight sequences were identified, of which 17 could be classified as African, 4 Amerindian and 2 European. Evidence for asymmetrical matings related to sex and ethnic group were found for 9 of the 11 populations with the most consistent finding the introduction of European genes through males. Results differ by community, so local factors are important.

This investigation was performed to identify and evaluate the distribution of all 15 Y-chromosome lineages belonging to the Q clade in a sample of natives from South America. One hundred and forty-eight individuals from 20 Native American populations, as well as 24 Asian samples including Eskimos, were tested with 18 biallelic loci that can identify all currently known lineages of the Y-Chromosome Q clade. Sequencing was performed in part of the sample (∼180,000 nucleotides, which detected, for instance, several downstream markers related to the Q1a3a lineage). No new mutation was found and Q1a3a was consistently found in high frequencies in all populations, followed at a much lower frequency by Q1a3*, while Q1a3a derived-lineages are probably population/tribe/region-specific. The number of basal Y chromosome lineages in North America is apparently higher than in South America due probably to a bottleneck during the South American colonization and/or more recent Circum-Arctic gene flow. Am. J. Hum. Biol., 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]