Quantitative trait loci for body growth and sex determination in the hermaphrodite teleost fish Sparus aurata L.

Summary

Gilthead sea bream (Sparus aurata L.) is an important marine fish in Mediterranean aquaculture. Sex determination by age and/or body weight is a critical life-history trait, the genetic basis for which is largely unknown in this sequential hermaphrodite species. Herein, we performed a partial genome scan to map quantitative trait loci (QTL) affecting body weight and sex using 74 informative microsatellite markers from 10 paternal half-sib families to construct nine linkage groups (LG). In total, four growth-related QTL (two chromosome-wide and two genome-wide) and six QTL related to sex determination (three pairs in three different LGs) were detected (two chromosome-wide and one genome-wide). The proportion of phenotypic variation explained by the body-weight QTL ranged from 9.3% to 17.2%, showing their potential for use in marker-assisted selection. The results obtained offer solid ground to investigate the structure and function of the genomic regions involved in the mechanisms of sex reversal.