Fine-scale genomic analyses of admixed individuals reveal unrecognized genetic ancestry components in Argentina

Abstract

Similarly to other populations across the Americas, Argentinean populations trace back their genetic ancestry into African, European and Native American ancestors, reflecting a complex demographic history with multiple migration and admixture events in pre- and post-colonial times. However, little is known about the sub-continental origins of these three main ancestries. We present new high-throughput genotyping data for 87 admixed individuals across Argentina. This data was combined to previously published data for admixed individuals in the region and then compared to different reference panels specifically built to perform population structure analyses at a sub-continental level. Concerning the Native American ancestry, we could identify four Native American components segregating in modern Argentinean populations. Three of them are also found in modern South American populations and are specifically represented in Central Andes, Central Chile/Patagonia, and Subtropical and Tropical Forests geographic areas. The fourth component might be specific to the Central Western region of Argentina, and it is not well represented in any genomic data from the literature. As for the European and African ancestries, we confirmed previous results about origins from Southern Europe, Western and Central Western Africa, and we provide evidences for the presence of Northern European and Eastern African ancestries.Author SummaryThe human genetic diversity in Argentina reflects demographic processes during which the European colonists invaded a territory where Native American populations were settled. During the colonial period, the slave trade also prompted many African people to move to Argentina. Little is known about the origins of these three continental ancestry components in Argentinean populations nowadays. Genotyping data for 87 admixed individuals throughout Argentina was generated and data from the literature was re-analyzed to shed light on this question. We confirmed that most of the European genetic ancestry comes from the South, although several individuals are related to Northern Europeans. We confirmed that the African origins in Argentina mainly trace back from Western and Central/Western regions, and we document some proportion of Eastern African origins poorly described before. As for the Native American ancestry, we identified that it can be divided into four main components that correspond to Central Chile/Patagonia, Subtropical and Tropical Forests, Central Andes and Central Western region of Argentina. In order to understand the specificity of the genetic diversity in Argentina, more effort is required to generate specific massive genomic knowledge at the local level.

Ancient Human Genomes and Environmental DNA from the Cement Attaching 2,000-Year-Old Head Lice Nits

“…In the latest genetic analyses using current time populations from the same region of this study, Calingasta (San Juan, Argentina), Luisi et al (2020) showed the greatest genetic affinity with people on the Pacific coast of central Chile. Current Sanjuaninos are unrelated to the original Huarpes, and are of a very recent ancestry, traced back to two or three generations only.…”

“…In the early 1800's, all native Huarpes of San Juan were 'deported' to Chile, due to the need for an indigenous workforce in Santiago de Chile (Michieli 1983). Luisi et al (2020) have shown that the lack of ancient samples from CWA, specifically San Juan province, prevents resolution of the origin of their indigenous people. The three Calingasta ancient mummies analysed in this study show for the first time that the original peoples of San Juan, Calingasta, came from Amazonia about 2,000 years BP -SJArg-2-Nit, and relate to Patagonian ancient samples about 1,500-1,000 years BP -SJArg-1-Tooth.…”

Disentangling signatures of selection before and after European colonization in Latin Americans

“…An ideal setting in which to test whether and how admixture contributed to genetic adaptation is Latin America. The genetic make-up of present day Latin Americans stems mainly from three ancestral populations: indigenous Native Americans, Europeans (mainly from the Iberian Peninsula), and Sub-Saharan Africans (Wang et al 2007;Moreno-Estrada et al 2013;Moreno-Estrada et al 2014;Homburger et al 2015;Chacon-Duque et al 2018;Luisi et al 2020) that were brought together starting ~500 years ago. The admixed genomes of Latin Americans are thus the result of an intermixing process between human populations that had been evolving independently for tens-of-thousands of years and that were suddenly brought together in a new environment.…”

Estandarización De Categorías Temporales Utilizadas en La Arqueología Del Centro De Argentina en Los Últimos 140 Años. Nuevos Usos De Viejos Datos

“…En el año 1573 llegan desde el norte grupos de europeos reconfigurando la economía, uso del espacio y relaciones económicas y sociales. Esto llevaría a la integración de los grupos prehispánicos a las formas sociales y económicas coloniales, manteniendo no obstante ello una continuidad cultural y biológica a nivel regional (p.ej., Luisi et al 2020).…”

“…La idea de reemplazo poblacional, extinción, migraciones, etc., también debe ser valorada a la luz de nuevos datos y no por tradiciones académicas del siglo pasado (o del antepasado). En este sentido los datos bioarqueológicos o genéticos (p.ej., Fabra et al 2012;Luisi et al 2020;Nores et al 2011), junto con interpretaciones paleoambientales (p.ej., Giorgis et al 2015;Izeta et al 2017;Silva et al 2011), deben ayudarnos a moldear una mejor interpretación del pasado.…”