Mapping quantitative trait loci for flesh fat content in common carp (Cyprinus carpio)

Flesh fat content is considered to play an important role in flesh quality in fish. Therefore, improving the fat content of fish fillets is one of the breeding goals in aquaculture. To provide data for genetic improvement and pave the way for marker-assisted selection (MAS) of flesh fat content in common carp (Cyprinus carpio), a genome-wide scan for quantitative trait loci (QTL) affecting flesh fat content was conducted on eight full-sib families containing a total of 522 progenies. All families were genotyped using 250 informative microsatellite markers and then a dual QTL mapping strategy was employed. Initially, the QTL analyses were conducted using a sib-pair model to take advantage of the full-sib pedigree structure. A half-sib model was then used to account for the large differences between the male and female recombination rates in common carp. Using these strategies, a genome-wide significant QTL was detected at 14 cM on LG31. This QTL explained 36.2% of the phenotypic variance. In addition, three QTL were identified on LG3, LG42, and LG45 at the chromosome-wide significant level with phenotypic variance explained that had a range of 15.3-19.5%. The identified QTL can potentially be applied in MAS programs, and can be explored further to help understand the biology of fat deposition in common carp.