Polymorphism in exons CpG rich regions of the cyp17-II gene affecting its mRNA expression and reproductive endocrine levels in female Japanese flounder (Paralichthys olivaceus)

► Single nucleotide polymorphisms were identified in Japanese flounder cyp17-II gene. ► Non-synonymous SNP in exon4 was associated with gene expression and steroid level. ► SNP in CpG rich region of exon6 was synonymous and added a new methylation site. ► SNPs and methylation level could affect gene expression and reproductive endocrine.