Figure 5 : Calfee et al. (2020) studied replicate
geographic ancestry clines in invasive honey bees (Apis
mellifera ). A) In 1957, western honey bees derived from
African populations (A. m. scutellata ; ‘scutellata’hereafter) escaped from a captive breeding programme in Rio Claro, São
Paulo. Scutellata populations both outcompeted and hybridized
with honey bee populations from Europe (previously introduced to the
Americas), forming invasive hybrid scutellata -European
populations. Replicate North and South American invasion routes
(indicated by arrows) of hybrid populations are shown with pink arrows,
with dates of first occurrence indicated. B) Geographic clines
in genome-wide ancestry. Curves are logistic cline models of ancestry
predicted by latitude, with dotted horizontal lines indicating the
latitude at which the model predicts 50% scutellata ancestry.C) Genomic location of scutellata ancestry in the two
hybrid zones shown in (B). Dashed line indicates mean scutellataancestry. Parallel peaks in excess scutellata ancestry, where
selection has outweighed migration to ‘push’ scutellata alleles
to high frequency hundreds of kilometres past the expected cline centre,
occur in chromosomes 1 and 11. Figure adapted from Calfee et al.(2020).