Migratory jackpot individuals fuel rapid ecotype shifts in Galaxias fishes (opens in new tab)

Adaptation is considered essential for species facing environmental change, but our understanding of the evolution of complex ecotypes remains limited. We show that a substantial genomic cluster of co-adapted alleles has repeatedly fuelled complex life-history shifts in fishes. Specifically, the majority of strong outlier loci underpinning repeated landlocking of formerly marine-migratory Galaxias lineages are co-located on a single chromosome. Phenotypic, behavioural and genomic comparisons ...