The Genomic Impact of European Colonization of the Americas

The human genetic diversity of the Americas has been affected 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 (1) the genetic structure, (2) the admixture profile, (3) the demographic history, and (4) sex-biased gene-flow 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.Introduction Results - Clustering of the Donor Individuals - The Ancestral Mosaic of American Populations -- African Ancestries’ Distribution Reflects the Complexity of the Slave Trade Dynamics -- Complex Variation of European Ancestries’ Distribution -- Native American Ancestry Distribution -- The Contribution of Jewish-Related Ancestry in the Americas - Inferring the Time of Admixture in American Populations - Assessing the Impact of Sex-Biased Admixture of the Americas - Reconstructing the Ancestry-Specific Demographic Histories of Admixed Populations Discussion STAR★Method