Genome-wide evolutionary signatures of climate adaptation in spotted sea bass inhabiting different latitudinal regions

Temperature is an important climatic factor that shapes the distribution of eurythermal species. Thermal adaptation of species is important to both evolutionary biology and climate-change biology because it frequently leads to latitudinal gradients of various phenotypes among populations. Spotted sea bass (Lateolabrax maculatus) has a broad latitudinal distribution range along the marginal seas of the Northwest Pacific, providing an excellent teleost model for climate adaptation studies. We generated over 8.57 million SNP loci using whole genome re-sequencing from 100 samples collected at 14 geographic loci. We built the phylogeographic structure and demographic history of L. maculatus and determined sea surface temperature as the key environmental factor and major driving force for genetic divergence and local adaptation. We also identified distinct selective signatures and functional genes underlying adaptive mechanisms and ecological tradeoffs in the southernmost and northernmost populations inhabiting distinct climatic and latitudinal zones. The results offer an opportunity to better understand the genetic basis of the phenotypic variation in eurythermal fishes inhabiting different climatic regions.