Population Genomics Provides Insights into the Population Structure and Climate-driven Adaptation of Collichthys Lucidus

Abstract

Background: Understanding the genetic structure and local adaptive evolutionary mechanisms of marine organisms is crucial for the conservation and management of biological resources. Collichthys lucidus is an ideal candidate for investigating population differentiation and local adaptation under heterogeneous environmental pressure. Results: To elucidate the fine-scale genetic structure and local thermal adaptation of C. lucidus, we performed restriction site-associated DNA tag sequencing (RAD-seq) of 177 individuals from 8 populations, and a total of 184,708 high-quality single nucleotide polymorphisms (SNPs) were identified. All the results revealed significant population structure with high support for two distinct genetic clusters, namely, the northern group (populations DL, TJ, LYG, NT, ZS, and WZ) and southern group (populations XM and ZH). The genetic diversity of the southern group was evidently lower than that of the northern group, which indicated that the southern group was possibly under climate-driven natural selection. In addition, a total of 314 SNPs were found to be significantly associated with temperature variation. Annotations of temperature-related SNPs suggested that genes involved in material (protein, lipid, and carbohydrate) metabolism and immune responses were critical for adaptation to spatially heterogeneous temperatures in natural C. lucidus populations. Conclusion: In the context of anthropogenic activities and environmental change, the results of the present population genomic work could make important contributions to the understanding of genetic differentiation and adaptation to changing environments.