biostudies-literatureUnknown7(2)Liu HThe sea-land transition is one of the most dramatic evolutionary changes and requires an adaptive genetic response to salinity changes and osmotic stress. Here, we used multi-species genomes and multi-tissue transcriptomes of the talitrid crustaceans, a living sea-land transition model, to investigate the adaptive genetic changes and osmoregulatory organs that facilitated their salinity adaptation. Genomic analyses detected numerous osmoregulatory genes in terrestrial talitrids undergoing gene family expansions and positive selection. Gene expression comparisons among species and tissues confirmed the gill being the primary organ responsible for ion transport and identified the genetic expression variation that enable talitrids to adapt to marine and land habitats. V-type H⁺-ATPMarine life science & technology205-217https://www.ebi.ac.uk/biostudies/studies/S-EPMC12102416biostudies-literatureOsmoregulatory evolution of gills promoted salinity adaptation following the sea-land transition of crustaceans.PMC12102416Liu HLiu ZHou ZLi SWang XfalseOsmoregulatory evolution of gills promoted salinity adaptation following the sea-land transition of crustaceans.The sea-land transition is one of the most dramatic evolutionary changes and requires an adaptive genetic response to salinity changes and osmotic stress. Here, we used multi-species genomes and multi-tissue transcriptomes of the talitrid crustaceans, a living sea-land transition model, to investigate the adaptive genetic changes and osmoregulatory organs that facilitated their salinity adaptation. Genomic analyses detected numerous osmoregulatory genes in terrestrial talitrids undergoing gene family expansions and positive selection. Gene expression comparisons among species and tissues confirmed the gill being the primary organ responsible for ion transport and identified the genetic expression variation that enable talitrids to adapt to marine and land habitats. V-type H⁺-ATP2025-01-01T00:00:00Z2025 May2026-06-01T11:44:39.971Z2026-04-08T11:56:19.737ZS-EPMC121024164041724910.1007/s42995-025-00298-6