Characterization of AFLP markers associated with growth in the Kuruma prawn, Marsupenaeus japonicus, and identification of a candidate gene.

Growth rate of the Kuruma prawn, Marsupenaeus japonicus is an important economic trait, with larger animals commanding higher market prices. To identify gene markers associated with growth, a genetic map of a full-sib F(2) intercross family of M. japonicus has previously been generated and quantitative trait loci (QTL) influencing weight, total length, and carapace length were identified. In this study, amplified fragment length polymorphism (AFLP) markers associated with the major QTL region, contributing 16% to phenotypic variation, were characterized. Flanking sequence has been obtained and allelic variants responsible for segregation patterns of these markers have been identified. The genomic sequence surrounding the AFLP band 7.21a, residing under the QTL peak, contains a gene sequence homologous to the elongation of very long chain fatty acids-like (ELOVL) protein family. A full-length mRNA (ELOVL-MJ) encoding this protein was isolated from M. japonicus, representing both the first ELOVL gene in crustacea and the first candidate gene identified via QTL studies in crustacea.