The Polymorphism of LvMMD2 and Its Association with Growth Traits in Litopenaeus vannamei.

The Pacific white shrimp Litopenaeus vannamei is one of the major economic aquaculture species. The growth trait is considered as the most important trait in L. vannamei aquaculture. Identification of the genetic components underlying growth-related traits in L. vannamei could be useful for the selective breeding of growth trait. Our previous work identified several growth-related SNPs by genome-wide association study (GWAS). Based on the assembled genome, we identified a new candidate gene (LvMMD2) beside the associated marker. This gene encodes the progestin and AdipoQ receptor 10 (PAQR10) protein. We further investigate the polymorphisms of LvMMD2 and their association with body weight of L. vannamei. By resequencing the coding region of LvMMD2, a total of 8 SNPs were identified, including 6 synonymous mutations and 2 nonsynonymous mutations. Association analyses based on a population of 322 individuals revealed that several SNPs located in the coding region of LvMMD2 were significantly associated with the body weight, especially the nonsynonymous mutation named as MMD_5 contributed the most association to the trait and it could explain 10.5% of phenotypic variance. In addition, several genes involved in growth and development have been identified as LvMMD2-interacting genes. These findings strongly suggested that LvMMD2 might be an important gene regulating the shrimp growth. More importantly, the MMD_5 could be a promising candidate locus for marker-assisted selection (MAS) of the body weight in L. vannamei.