Human Biology Open Access Pre-Prints

Document Type

Article

Anticipated Volume

96

Anticipated Issue

2

Abstract

Genetic and archaeological studies indicate that the American continent has undergone multiple waves of human migration, shaping a complex population genetic structure comprising three major ethnic groups—Native American, European, and African—unevenly distributed across the continent. In this study, we examined MAPT (17q21.31) haplotype and sub-haplotype frequencies by analyzing two SNP markers (rs10514879 and rs199451) in three South American groups from distinct countries: Waorani (Ecuadorian Amazon), Jujuy (Northwestern Argentina), and Afro-Colombian (Northwestern Colombia). To broaden the scope, we also genotyped four short tandem repeats (STRs) within the 17q21.31 chromosomal region and compiled H2 haplotype and sub-haplotype frequency data for 97 worldwide populations (Africa: 26; Asia: 37; Europe: 19; America: 15). We used the publicly available genome-wide databases 1000G and ALFRED. Genetic heterogeneity among population clusters, classified by geographic region, was examined by hierarchical AMOVA. Likewise, we explored genetic affinities between the Waorani, Afro-Colombian, and Jujuy samples and worldwide collections using factorial correspondence analysis (FCA). The H1 haplotype predominated in all study populations. Notably, H2 varied among them: in Afro-Colombians, H2 was found at a frequency of 0.058, with equal representation of sub-haplotypes H2’ and H2D. Among Native American groups (Waorani and Jujuy), the H2 haplotype was virtually absent, with only H2D detected in Jujuy at a very low frequency (0.007). Analysis of a set of STRs from the MAPT region identified distinct genetic features in Native American groups, characterized by markedly low heterozygosity. Waorani and Karitiana exhibited strikingly low genetic diversity, reflecting a significant degree of population isolation and, consequently, a potentially strong impact of genetic drift. In summary, our analyses demonstrate the utility of MAPT haplotypes in detecting the effects of population isolation, genetic drift, and admixture on the gene pool of the South American samples examined. MAPT haplotypes may serve as reliable lineage markers, given their ability to differentiate ethnic groups and trace ancestral chromosomes. They have proved to be informative and cost-effective tool for exploring ancestry, geographic origins, and demographic history in anthropological studies.

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