Genomic architecture of parallel ecological divergence: Beyond a single environmental contrast.

Morales HE, Faria R, Johannesson K, Larsson T, Panova M, Westram AM, Butlin RK

Sci Adv 5 (12) eaav9963 [2019-12-00; online 2019-12-04]

The study of parallel ecological divergence provides important clues to the operation of natural selection. Parallel divergence often occurs in heterogeneous environments with different kinds of environmental gradients in different locations, but the genomic basis underlying this process is unknown. We investigated the genomics of rapid parallel adaptation in the marine snail Littorina saxatilis in response to two independent environmental axes (crab-predation versus wave-action and low-shore versus high-shore). Using pooled whole-genome resequencing, we show that sharing of genomic regions of high differentiation between environments is generally low but increases at smaller spatial scales. We identify different shared genomic regions of divergence for each environmental axis and show that most of these regions overlap with candidate chromosomal inversions. Several inversion regions are divergent and polymorphic across many localities. We argue that chromosomal inversions could store shared variation that fuels rapid parallel adaptation to heterogeneous environments, possibly as balanced polymorphism shared by adaptive gene flow.

NGI Stockholm (Genomics Applications) [Service]

NGI Stockholm (Genomics Production) [Service]

National Genomics Infrastructure [Service]

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PubMed 31840052

DOI 10.1126/sciadv.aav9963

Crossref 10.1126/sciadv.aav9963

pii: aav9963
pmc: PMC6892616