Data from: Population genomic analysis uncovers African and European admixture in Drosophila melanogaster populations from the southeastern United States and Caribbean Islands

Drosophila melanogaster is postulated to have colonized North America in
the past several 100 years in two waves. Flies from Europe colonized the
east coast United States while flies from Africa inhabited the Caribbean,
which if true, make the south-east US and Caribbean Islands a secondary
contact zone for African and European D. melanogaster. This scenario has
been proposed based on phenotypes and limited genetic data. In our study,
we have sequenced individual whole genomes of flies from populations in
the south-east US and Caribbean Islands and examined these populations in
conjunction with population sequences from the west coast US, Africa, and
Europe. We find that west coast US populations are closely related to the
European population, likely reflecting a rapid westward expansion upon
first settlements into North America. We also find genomic evidence of
African and European admixture in south-east US and Caribbean populations,
with a clinal pattern of decreasing proportions of African ancestry with
higher latitude. Our genomic analysis of D. melanogaster populations from
the south-east US and Caribbean Islands provides more evidence for the
Caribbean Islands as the source of previously reported novel African
alleles found in other east coast US populations. We also find the border
between the south-east US and the Caribbean island to be the admixture hot
zone where distinctly African-like Caribbean flies become genomically more
similar to European-like south-east US flies. Our findings have important
implications for previous studies examining the generation of east coast
US clines via selection.