Genome-wide association study identifies novel candidate genes linked to acute and chronic thermal stress resilience in olive flounder (Paralichthys olivaceus)

Acute and chronic high-temperature stress negatively impact olive flounder ( Paralichthys olivaceus ) aquaculture, weakening immune function and increasing mortality. This study conducted a genome-wide association study (GWAS) to identify genetic markers linked to thermal stress resilience. A total of 384 fish were exposed to acute stress (29 °C for 30 min and 1 h) and chronic stress (19.8–30 °C for 16 days). Genomic DNA from 329 deceased and 55 surviving fish was genotyped using a 70 K SNP chip, yielding 57,638 SNPs from 376 fish after quality filtering. GWAS identified 34 SNPs associated with both acute and chronic thermal stress on chromosomes 4, 10, 11, 15, 18, 19, and 23, surpassing the suggestive ( p < 1 × 10 −4 ) and Bonferroni-corrected ( p < 8.6 × 10 −7 ) thresholds. Genes myhc , nlrc5 , hydin , and gfod1 were linked to thermal stress. These findings may support marker-assisted selection for thermal stress resilience strains, promoting sustainable aquaculture. • GWAS identified SNPs linked to acute and chronic thermal stress in olive flounder. • SNPs for acute heat stress were found on chromosomes 4, 15, and 23. • SNPs for chronic heat stress were identified on chromosomes 18 and 19. • A total of 34 SNPs were significantly associated with thermal stress response. • Annotated genes myhc , nlrc5 , hydin , and gfod1 were linked to heat stress resilience.