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

Abstract

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.

Chromosome‐level genome assembly and population genomic analysis reveal evolution and local adaptation in common hairfin anchovy (Setipinna tenuifilis)

“…Variability in water temperature is known to drive divergence in marine species by selecting thermal tolerance at multiple life history stages, affecting traits related to growth, reproduction and movement(Johansen & Jones, 2011;Pankhurst & Munday, 2011;Rountrey et al, 2014). Indeed, other studies have demonstrated that temperature is a significant determinant of adaptive divergence and genetic structure in marine species, such as Parastichopus californicus exhibiting different bottom temperatures in the coastal region of British Columbia and southeastern Alaska(Xuereb et al, 2018), and Sillago japonica(Han et al, 2021) and Lateolabrax maculatus (;Chen et al, 2021) inhabiting spatially varying temperature regimes in the Northwest Pacific Ocean. Even though temperature sometimes may not be the direct causation of selection, other factors closely associated with temperature could directly contribute to adaptation.For example, rising water temperatures could reduce the overall aerobic scopes of aquatic ectotherms and smaller aerobic scopes imply that less energy remains for supporting physiological performance and fitness-related activities(Pörtner & Knust, 2007).Overall, the obvious heterogeneity in environmental factors might have resulted in the divergent selection of specific genes,…”