Whole-genome analysis of Mustela erminea finds that pulsed hybridization impacts evolution at high latitudes.

Colella, Jocelyn P.; Lan, Tianying; Schuster, Stephan C.; Talbot, Sandra L.; Cook, Joseph A.; Lindqvist, Charlotte

At high latitudes, climatic shifts hypothetically initiate recurrent episodes of divergence by isolating populations in glacial refugia—ice-free regions that enable terrestrial species persistence. Upon glacial recession, populations subsequently expand and often come into contact with other independently diverging populations, resulting in gene flow. To understand how recurrent periods of isolation and contact may have impacted evolution at high latitudes, we investigated introgression dynamics in the stoat (Mustela erminea), a Holarctic mammalian carnivore, using whole-genome sequences. We identify two spatio-temporally distinct episodes of introgression coincident with large-scale climatic shifts: contemporary introgression in a mainland contact zone and ancient contact ~200 km south of the contemporary zone, in the archipelagos along North America's North Pacific Coast. Repeated episodes of gene flow highlight the central role of cyclic climates in structuring high-latitude diversity, through refugial divergence and introgressive hybridization. When introgression is followed by allopatric isolation (e.g., insularization) it may ultimately expedite divergence. Jocelyn Colella et al. report whole-genome sequences of 10 stoats (Mustela erminea) from four regions of glacial refugia. They find evidence for two past introgressive events between lineages that coincide with interglacial periods, a pattern that may extend to other high–latitude species.

NORTH America; ERMINE; SPECIES hybridization; NUCLEOTIDE sequencing; COASTS; ARCHIPELAGOES

Communications Biology, 2018, Vol 1, Issue 1, pN.PAG

2399-3642

Academic Journal

10.1038/s42003-018-0058-y