Rapid global differentiation of migratory phenotypes in Bar-tailed Godwits

Activiteit: Academic presentationAcademic


Migratory phenotypes are generally considered heritable and under strong selection, and therefore relatively inflexible in changing conditions. However, divergent patterns observed within species attest to recent evolution of migratory phenotypes, and colonization of flyways, since the Last Glacial Maximum (LGM; <20,000 years). Bar-tailed Godwits (Limosa lapponica) include five recognized subspecies distinguishedby plumage, body size, annual-cycle phenology, and distance and direction of migration. Using genome-wide information (>20,000 single-nucleotide polymorphisms) across all major breeding populations, we assessed the fine-scale genetic structure and evolutionary history of the species. Our analyses support a primary divergence of two major clades (Beringia and western Palaearctic), which later admixed to form the NE Russian subspecies menzbieri. We found clear geographic structure within the Alaska breeding subspecies baueri, which reflects latitudinal clines in morphology and migration timing. In contrast, we found no genetic structure within taymyrensis, despite the use of two completely distinct migration routes in that subspecies. In general, magnitude of phenotypic differences did not match global genetic population structure, suggesting that migratory differences either do not impede gene flow, or are too recent to leave a genome-wide signal. We propose that population structure in Bar-tailed Godwits is mainly driven by phylogeographic processes (e.g. post-LGM changes in habitat and sea level) rather than isolation by phenotypic differences. Ongoing work will further reconstruct the temporal and spatial patterns of diversification, and explicitly examine the impact of phenotypic differences on gene flow.
Evenementstitel137th American Ornithological Society Annual Meeting: Birds on the Edge - Dynamic Boundaries
LocatieAnchorage, United States, AlaskaToon op kaart
Mate van erkenningInternational