Genome-wide association analysis of heat tolerance in the northern pike (Esox Lucius)

Abstract

The northern pike is one of the important economic fish in Xinjiang, China. However, its survival and the expansion of aquaculture areas have been seriously affected by the increase in water temperature caused by global warming and the extremely high temperature in summer. Therefore, screening molecular markers and candidate genes will be helpful for the selection of heat tolerance of the northern pike, which will be beneficial to its better survival and expansion. In this study, the heat tolerance and cumulative survival time of the northern pike were measured under high temperature stress (26 °C ~ 35 °C). Genome-wide association study (GWAS) was used to analyze the loci and genes related to heat tolerance of the northern pike. A total of 77,617 single nucleotide polymorphisms (SNPs) were obtained through genotyping by sequencing (GBS) and used for subsequent GWAS analysis. 9 significant SNPs were obtained from GWAS analysis, which were assigned to eight chromosomes. By analyzing these significant SNPs, we predicted four candidate genes (clstn2, htr4, atp13a3 and schip1) related to respiration, ion channels, or obesity. The heat tolerance of the northern pike was determined by a variety of mechanisms regulated by various genes. The results observed in this study provide insights into the genetic basis of heat tolerance in the northern pike and contribute to the cultivation of heat-resistant fry.