The Genetic Legacy of the Pre-Colonial Period in Contemporary Bolivians

Abstract

Only a few genetic studies have been carried out to date in Bolivia. However, some of the most important (pre)historical enclaves of South America were located in these territories. Thus, the (sub)-Andean region of Bolivia was part of the Inca Empire, the largest state in Pre-Columbian America. We have genotyped the first hypervariable region (HVS-I) of 720 samples representing the main regions in Bolivia, and these data have been analyzed in the context of other pan-American samples (>19,000 HVS-I mtDNAs). Entire mtDNA genome sequencing was also undertaken on selected Native American lineages. Additionally, a panel of 46 Ancestry Informative Markers (AIMs) was genotyped in a sub-set of samples. The vast majority of the Bolivian mtDNAs (98.4%) were found to belong to the main Native American haplogroups (A: 14.3%, B: 52.6%, C: 21.9%, D: 9.6%), with little indication of sub-Saharan and/or European lineages; however, marked patterns of haplogroup frequencies between main regions exist (e.g. haplogroup B: Andean [71%], Sub-Andean [61%], Llanos [32%]). Analysis of entire genomes unraveled the phylogenetic characteristics of three Native haplogroups: the pan-American haplogroup B2b (originated ∼21.4 thousand years ago [kya]), A2ah (∼5.2 kya), and B2o (∼2.6 kya). The data suggest that B2b could have arisen in North California (an origin even in the north most region of the American continent cannot be disregarded), moved southward following the Pacific coastline and crossed Meso-America. Then, it most likely spread into South America following two routes: the Pacific path towards Peru and Bolivia (arriving here at about ∼15.2 kya), and the Amazonian route of Venezuela and Brazil southwards. In contrast to the mtDNA, Ancestry Informative Markers (AIMs) reveal a higher (although geographically variable) European introgression in Bolivians (25%). Bolivia shows a decreasing autosomal molecular diversity pattern along the longitudinal axis, from the Altiplano to the lowlands. Both autosomes and mtDNA revealed a low impact (1–2%) of a sub-Saharan component in Bolivians.

Paleogenetic Studies in Guajajara Skeletal Remains, Maranhão State, Brazil

“…In the present study, the samples were aligned and subjected to phylogenetic analyses with other groups of samples from previous mitochondrial studies [24,25,[45][46][47]. An NJ tree (Figure 2) of this data set gives tenuous support for separation into seven clusters.…”

Primer genoma mitocondrial en restos humanos de la Costa de Santa Cruz, Argentina

“…Asimismo, al interior de cada subhaplogrupo se está avanzando en la definición de clados con distribuciones geográficas acotadas, que se habrían diferenciado localmente (Gayà-Vidal et al 2011;Bodner et al 2012;de Saint Pierre et al 2012a,b;García et al 2012;Motti, 2012;Taboada-Echalar et al 2013).…”

Revisión sobre los marcadores del origen biogeográfico y su aplicación en la investigación forense

“…De tal manera, se deben encontrar conjuntos de marcadores que separen estos grupos de poblaciones; es decir, con elevados niveles de Fst entre poblaciones [8]. Pero debe ser con igual poder de resolución; por el contrario, se puede infra o sobreestimar la proporción de uno de los componentes, como ya ha sido observado en el análisis de población boliviana por Taboada [9] y Galanter [10]. Posteriormente, lo que se mide en un individuo es el ancestro genómico o nivel de ancestro gené-tico, siendo este el nivel promedio de mezcla calculado en el genoma, en relación con los aim [7].…”