Admixture in Africanized honey bees (Apis mellifera) from Panamá to San Diego, California (U.S.A.) honey bee dataset

The Africanized honey bee (AHB) is a New World amalgamation of several
subspecies of the western honey bee (Apis mellifera), a diverse taxon
historically grouped into four major biogeographic lineages: A (African),
M (Western European), C (Eastern European), and O (Middle Eastern). In
1956, accidental release of experimentally bred “Africanized” hybrids from
a research apiary in Sao Paulo, Brazil, initiated a hybrid species
expansion that now extends from northern Argentina to northern California
(U.S.A.). Here, we assess nuclear admixture and mitochondrial ancestry in
60 bees from four countries (Panamá; Costa Rica, Mexico; U.S.A) across
this expansive range to assess ancestry of AHB several decades following
initial introduction and test the prediction that African ancestry
decreases with increasing latitude. We find that AHB nuclear genomes from
Central America and Mexico have predominately African genomes (76–89%)
with smaller contributions from Western and Eastern European lineages.
Similarly, nearly all honey bees from Central America and Mexico possess
mitochondrial ancestry from the African lineage with few individuals
having European mitochondria. In contrast, AHB from San Diego (CA) show
markedly lower African ancestry (38%) with substantial genomic
contributions from all four major honey bee lineages and mitochondrial
ancestry from all four clades as well. Genetic diversity measures from all
New World populations equal or exceed those of ancestral populations.
Interestingly, the feral honey bee population of San Diego emerges as a
reservoir of diverse admixture and high genetic diversity, making it a
potentially rich source of genetic material for honey bee breeding.