Genetic Diversity and Signatures of Selection in the Roughskin Sculpin (Trachidermus fasciatus) Revealed by Whole Genome Sequencing

SIMPLE SUMMARY: The roughskin sculpin (Trachidermus fasciatus) was previously a locally abundant species in China, but the habitat required for the survival and breeding of this species has been seriously damaged. Its resources have been almost depleted, and it has been listed as a national second-class protected animal. In recent years, the population of roughskin sculpin has recovered in the natural environment through enhancement programs and the release of juveniles. However, the effects of released roughskin sculpin on wild populations’ genetic structure and diversity remain unclear. In this study, the whole-genome resequencing of two cultured populations and one wild population showed that the two cultured populations have similar genetic diversity compared with the wild population. In addition, artificial feeding affected the formation of traits of roughskin sculpin. The finding provides data support for the resource recovery of roughskin sculpin. ABSTRACT: The roughskin sculpin (Trachidermus fasciatus) is an endangered fish species in China. In recent years, artificial breeding technology has made significant progress, and the population of roughskin sculpin has recovered in the natural environment through enhancement programs and the release of juveniles. However, the effects of released roughskin sculpin on the genetic structure and diversity of wild populations remain unclear. Studies on genetic diversity analysis based on different types and numbers of molecular markers have yielded inconsistent results. In this study, we obtained 2,610,157 high-quality SNPs and 494,698 InDels through whole-genome resequencing of two farmed populations and one wild population. Both farmed populations showed consistent levels of genomic polymorphism and a slight increase in linkage compared with wild populations. The population structure of the two farmed populations was distinct from that of the wild population, but the degree of genetic differentiation was low (overall average Fst = 0.015). Selective sweep analysis showed that 523,529 genes were selected in the two farmed populations, and KEGG enrichment analysis showed that the selected genes were related to amino acid metabolism, which might be caused by artificial feeding. The findings of this study provide valuable additions to the existing genomic resources to help conserve roughskin sculpin populations.