RESUMO
Numerous studies of human populations in Europe and Asia have revealed a concordance between their extant genetic structure and the prevailing regional pattern of geography and language. For native South Americans, however, such evidence has been lacking so far. Therefore, we examined the relationship between Y-chromosomal genotype on the one hand, and male geographic origin and linguistic affiliation on the other, in the largest study of South American natives to date in terms of sampled individuals and populations. A total of 1,011 individuals, representing 50 tribal populations from 81 settlements, were genotyped for up to 17 short tandem repeat (STR) markers and 16 single nucleotide polymorphisms (Y-SNPs), the latter resolving phylogenetic lineages Q and C. Virtually no structure became apparent for the extant Y-chromosomal genetic variation of South American males that could sensibly be related to their inter-tribal geographic and linguistic relationships. This continent-wide decoupling is consistent with a rapid peopling of the continent followed by long periods of isolation in small groups. Furthermore, for the first time, we identified a distinct geographical cluster of Y-SNP lineages C-M217 (C3*) in South America. Such haplotypes are virtually absent from North and Central America, but occur at high frequency in Asia. Together with the locally confined Y-STR autocorrelation observed in our study as a whole, the available data therefore suggest a late introduction of C3* into South America no more than 6,000 years ago, perhaps via coastal or trans-Pacific routes. Extensive simulations revealed that the observed lack of haplogroup C3* among extant North and Central American natives is only compatible with low levels of migration between the ancestor populations of C3* carriers and non-carriers. In summary, our data highlight the fact that a pronounced correlation between genetic and geographic/cultural structure can only be expected under very specific conditions, most of which are likely not to have been met by the ancestors of native South Americans.
Assuntos
Cromossomos Humanos Y/genética , Haplótipos/genética , Indígenas Sul-Americanos/genética , Repetições de Microssatélites/genética , América Central , Europa (Continente) , Genótipo , Geografia , Humanos , Idioma , Linguística , Masculino , Filogenia , Polimorfismo de Nucleotídeo Único , Grupos Populacionais/genética , América do SulRESUMO
Twelve Y-chromosomal short tandem repeats (STRs) DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438 and DYS439 were studied in the three major ethnic groups from Ecuador: Mestizos, Native Amerindians (Kichwas, Quichuas) and Afro-Ecuadorians aiming to construct a representative database for this region in Latin America. All three populations exhibit high haplotypes diversities. Analysis of molecular variance (AMOVA) reveals significant differentiation between the Mestizos, the Kichwas and the Afro-Ecuadorians. The analysis of a hunter-gatherer group of Native Amerindians from the Amazonian provinces of Ecuador, the Waoranis (Huaorani) revealed markedly reduced haplotypes variability and a large genetic distance to the major Ecuadorian populations.
Assuntos
População Negra/genética , Cromossomos Humanos Y , Etnicidade/genética , Indígenas Sul-Americanos/genética , Repetições de Microssatélites/genética , Equador , Variação Genética , Genética Populacional , Genótipo , Geografia , Haplótipos , Humanos , Masculino , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase , Controle de QualidadeRESUMO
Allelic frequencies and haplotypic composition of 305 male unrelated individuals from the Caribbean Colombian states of Atlántico, Bolívar, Cesar, Córdoba, Guajira, Magdalena and Sucre, were determined using 16 Y-chromosome STR loci. Two hundred and ninety three (293) haplotypes were identified, of which 283 were unique and the other 10 were found twice or thrice in the Caribbean population tested. Haplotypic diversity surpassed the values obtained in other populations, ranging from 99.66% in the population of Sucre to 99.99% in the population of Córdoba. We also calculated the overall haplotypic diversity (99.97%) and the discrimination power of these haplotypes (96.1%) in these groups. Analysis of molecular variance (AMOVA) for 10 Colombian and Spanish populations (3139 haplotypes) reveals low differentiation between the Colombian populations of mainly European descent and large distance to Afroamerican populations living in Colombia.