Mapping QTL Related To Body Weight And Body Thickness In Crucian Carp (Carassius Auratus)

Carassius auratus, widely distributed in China, has very high values in commerceand ornament as well as the edible values. The annual production of Carassius auratusin China summed up to200million ton. In recent years, fish resources are under threatfrom overfishing and water pollution. It is necessary to draw support from markerassisted selection (MAS) to enrich superior genes accurately and increase yield rapidly.In this study,384SSR markers were selected to analyze the genomic DNA of178progenies from an inbred Carassius auratus F2family, the genetic linkage map wasconstructed and quantitative trait loci (QTL) for body weight and body thickness wereidentified on the map.By using the least square method in SPSS13.0software,38SSR markers weredetected closely relating to growth traits:27markers had a significant impact on bodyweight,25markers on body thickness, and14markers both on body weight andthickness. Furthermore, JE13499was found to have a highly significant correlationwith the two growth traits (P<0.01). Meanwhile, the genotypes of these correlative lociwere determined. Furthermore, by using BLAST online in NCBI, the homologyidentity of these38EST-SSRs markers was determined. Results shown that,10markers had significant similarity with the sequences in GenBank(E<e-20).The genetic linkage map based on SSR markers with Joinmap4.0softwareconsisted of332markers, which were distributed on49linkage groups ranging in sizefrom9.5to128.9cM. The total length was3246.4cM, with an average spacing ofapproximately11.5cM between loci, and the map cover81.9%of the genome. Thelinkage groups ranged from2to19markers with an average of7.The locations of QTL for body weight and body thickness were detected usingMAPQTL6.0software. The thresholds were set according to a permutation test (1000repetitions) applied to each group data. The results indicated that a total of14QTLcontaining32SSR markers were distributed on11linkage groups. Seven QTLcontaining20SSR markers were related to body weight, and the others containing14SSR markers were related to body thickness. Moreover, two overlap regions which related to both the two growth traits were detected, one was on LG4(HLJY296-JE385),the other was on LG13(HLJY244).In this study, a genetic linkage map of Carassius auratus was constructed, andQTL for body weight and body thickness were mapped.