Polymorphism in the insulin-related peptide gene and its association with growth traits in the Pacific oyster Crassostrea gigas

► Polymorphisms of the oIRP gene were evaluated for associations with growth performance. ► Six SNPs were significantly associated with growth performance. ► Two haplotypes might be the most advantageous haplotypes for growth traits in Crassostrea gigas. ► The oIRP gene could influence growth performance of C. gigas.