The genomic impact of European colonization of the Americas

Abstract

The human genetic diversity of the Americas has been shaped by several events of gene flow that have continued since the Colonial Era and the Atlantic slave trade. Moreover, multiple waves of migration followed by local admixture occurred in the last two centuries, the impact of which has been largely unexplored.Here we compiled a genome-wide dataset of ~12,000 individuals from twelve American countries and ~6,000 individuals from worldwide populations and applied haplotype-based methods to investigate how historical movements from outside the New World affected i) the genetic structure, ii) the admixture profile, iii) the demographic history and iv) sex-biased geneflow dynamics, of the Americas.We revealed a high degree of complexity underlying the genetic contribution of European and African populations in North and South America, from both geographic and temporal perspectives, identifying previously unreported sources related to Italy, the Middle East and to specific regions of Africa.

Exchanging fluids

“…Genetic diversity in Latin America has also increased across the centuries as a result of the complex patterns of African slavery and European migration. The complexity is both geographic (in terms of origins) and temporal (in terms of when populations were introduced to Latin America; Ongaro et al, 2019). Between the sixteenth and nineteenth centuries, the bulk of efforts shifted several times from one region of Africa to another for the extraction of slaves brought to Latin America, mainly through four cycles that concentrated, initially, on coastal regions of Western sub-Saharan Africa, such as Guinea, Angola, and the Benin-Dahomey stretch, and subsequently on more inland and Eastern regions, such as Mozambique (Bueno, 2003).…”

“…This increasing diversity across centuries can also be observed in the case of European migration, which was initially of predominantly Iberian origin and subsequently of mostly Italian and German origins to certain Latin American regions, such as Argentina (Fausto, 1999). Cutting-edge evidence has been presented of important genomic proportions of Jewish and Middle Eastern groups in several Latin American countries (Ongaro et al, 2019). This pattern of genetic diversity has resulted in substantial heterogeneity among Latino groups (Conomos et al, 2016).…”