The genetic structure and adaptation of Andean highlanders and Amazonian dwellers is influenced by the interplay between geography and culture

Abstract

Western South America was one of the worldwide cradles of civilization. The well known Inca Empire was the tip of the iceberg of a cultural and biological evolutionary process that started 14-11 thousand years ago. Genetic data from 18 Peruvian populations reveal that: (1) The between-population homogenization of the central-southern Andes and its differentiation with respect to Amazonian populations of similar latitudes do not extend northward. Instead, longitudinal gene flow between the northern coast of Peru, Andes and Amazonia accompanied cultural and socioeconomic interactions revealed by archeological studies. This pattern recapitulates the environmental and cultural differentiation between the fertile north, where altitudes are lower; and the arid south, where the Andes are higher, acting as a genetic barrier between the sharply different environments of the Andes and Amazonia (2). The genetic homogenization between the populations of the arid Andes is not only due to migration during the Inca Empire or the subsequent colonial period. It started at least during the earlier expansion of the pre-Inca Wari Empire (600-1000 YBP) (3) This demographic history allowed for cases of positive natural selection in the high and arid Andes vs. the low Amazon tropical forest: in the Andes, HAND2-AS1 (heart and neural crest derivatives expressed 2 antisense RNA1, related with cardiovascular function) and DUOX2 (dual oxidase 2, related to thyroid function and innate immunity) genes; in the Amazon, the gene encoding for the CD45 protein, essential for antigen recognition by T/B lymphocytes in viral-host interaction, consistent with the host-virus arms race hypothesis.

Detecting geospatial patterns of Plasmodium falciparum parasite migration in Cambodia using optimized estimated effective migration surfaces

“…The Mekong River running through southeastern Cambodia as well as the urbanized area of Phnom Penh, may both have contributed to reduced parasite migration in this part of Cambodia. The fact that detected migration hotspots and barriers were geographically related with landcover and hydrologic features underscores the role that geography plays in shaping parasite population structure, which is consistent with findings from other studies, for example, a major migration barrier was detected around the Andes Mountains in Peru [56].…”

Genetic assessment reveals no population substructure and divergent regional and sex-specific histories in the Chachapoyas from northeast Peru

“…From the genetics point of view, two recent independent studies [ 60 , 61 ] have identified east-west gene flow linking the north Peruvian coast and highlands with Amazonian groups to the east of the northern Andes. Interestingly, one of these studies has found gene flow between the Chachapoyas and populations from the Jivaroan ethnolinguistic stock such as the Awajún and Candoshi [ 61 ]. This evidence gives further support to our finding despite the lack of published historical works on ancient or recent migrations from Jivaroan populations towards the Chachapoya territory or vice versa.…”

How Ancestry Influences the Chances of Finding Unrelated Donors: An Investigation in Admixed Brazilians

“…To infer the genetic ancestry for Brazilians, we used the three parental populations: 502 African and 503 European individuals from the 1000 Genomes Project phase-III ( 33 ), and 234 Native American individuals ( 34 ).…”