How a bird's DNA rewiring explains migration patterns, and what it means for evolution
Researchers decoded the genetic architecture of migration in songbirds by identifying chromosome inversions—structural DNA rearrangements—that persist across populations. The discovery shows how evolution locks in adaptive traits and offers a new toolkit for understanding how species adapt to changing environments, with implications for conservation strategy and our understanding of how complex traits evolve.
Originaltitel: Inversions maintain differences between migratory phenotypes of a songbird
<p>Structural rearrangements have been shown to be important in local adaptation and speciation, but have been difficult to reliably identify and characterize in non-model species. Here we combine long reads, linked reads and optical mapping to characterize three divergent chromosome regions in the willow warbler Phylloscopus trochilus, of which two are associated with differences in migration and one with an environmental gradient. We show that there are inversions (0.4-13 Mb) in each of the regions and that the divergence times between inverted and non-inverted haplotypes are similar across the regions (similar to 1.2 Myrs), which is compatible with a scenario where inversions arose in either of two allopatric populations that subsequently hybridized. The improved genomes allow us to detect additional functional differences in the divergent regions, providing candidate genes for migration and adaptations to environmental gradients.</p>