A comprehensive linkage map and QTL map for carcass traits in a cross between Giant Grey and New Zealand White rabbits

Genomic resources for the rabbit are still limited compared to many other livestock species. The genomic sequence as well as linkage maps have gaps that hamper their use in rabbit genome research. Therefore, the aims of this study were the improvement of existing linkage maps and the mapping of quantitative trait loci (QTL) for carcass and meat quality traits. The study was performed in a F2 population of an initial cross between Giant Grey (GG) and New Zealand White (NZW) rabbits. The population consisted of 363 F2 animals derived from 9 F1 bucks and 33 F1 does. 186 microsatellite and three SNP markers were informative for mapping.

Out of 189 markers, which could be assigned to linkage groups, 110 markers were genetically mapped for the first time. The average marker distance was 7.8 cM. The map across all autosomes reached a total length of 1419 cM. The maternal linkage map was 1.4 times longer than the paternal. All linkage groups could be anchored to chromosomes. On the basis of the generated genetic map, we identified a highly significant QTL (genome-wide significance p < 0.01) for different carcass weights on chromosome 7 with a peak position at 91 cM (157 Mb), a significant QTL (p < 0.05) for bone mass on chromosome 9 at 61 cM (65 Mb), and another one for drip loss on chromosome 12 at 94 cM (128 Mb). Additional suggestive QTL were found on almost all chromosomes. Several genomic loci affecting the fore, intermediate and hind parts of the carcass were identified. The identified QTL explain between 2.5 to 14.6% of the phenotypic variance in the F2 population.

The results present the most comprehensive genetic map and the first genome-wide QTL mapping study for carcass and meat quality traits in rabbits. The identified QTL, in particular the major QTL on chromosome 7, provide starting points for fine mapping and candidate gene search. The data contribute to linking physical and genetic information in the rabbit genome.