Identification of SNPs in the 5′-flanking region and 3′-UTR of theMIHgene and their association with precocity of the Chinese mitten crabEriocheir sinensis

Moult-inhibiting hormone (MIH), an important regulator of steroidogenesis, inhibits the synthesis of ecdysteroid in Y-organ (YO) and plays a significant role in the regulation of moulting and post-embryonic development of crustacean. Because unsuccessful moulting have been widely observed in precocious crabs, we investigated whether genetic variants in the 5′-flanking region and 3′-untranslated region (3′-UTR) of the MIH gene are associated with precocity of the Chinese mitten crab. Thirty individual DNA samples were sequenced to search for SNPs in the 5′-flanking region and 3′-UTR of the MIH gene. Five SNPs (g.196 T>A, g.230 C>T, g.305 T>C, g.323 C>A and g.372 C>T) in the 5′-flanking region and 6 SNPs (g.2677 C>T, g.2759 T>A, g.2807 T>C, g.3042 A>G, g.3088 T>G and g.3295 T>G) in the 3′-UTR of the MIH gene were selected for the individual genotyping in a two-stage association study. We found that a SNP g.3088 T>G in the 3′-UTR of MIH gene was consistently associated with precocity of the Chinese mitten crab in stage 1 and stage 2, with a per-allele OR (Odds Ratio) of 1.469 (95% CI: 1.169–1.844) after two stages combined (P = 0.001). However, no significant associations were observed between the other 10 SNPs and precocity of the Chinese mitten crab. To our best knowledge, this is the first association study between various SNP genotypes and phenotype attributes in Chinese mitten crab. Our findings suggest that the SNP g.3088 T>G may be a candidate marker for effective marker-assisted selection to decrease the precocity of the Chinese mitten crab in future studies.