Genome-wide interval mapping using SNP identifies new QTL for growth, body composition, meat quality and several physiological parameters in an F2 intercross between Fat and Lean chicken lines
Résumé
Availability of the chicken genome brings new possibilities for improving selection. The identification of chromosomal regions (QTL) controlling the traits is a first step to marker assisted selection. This study aims at using a F2 design produced by crossing INRA lines divergently selected for abdominal fatness and a medium density genetic map (127 microsatellites and 1285 SNP) allowing the study of all the available chicken genome (28 first chromosomes and the Z chromosome), including genomic regions not covered in previous studies. QTL mapping was performed for growth and body composition at 9 weeks, meat quality and some physiological parameters; for a total of 26 traits. Two mapping strategies were applied using QTLMap: single-QTL or multi-QTL, the later testing if more than one QTL affecting the same trait could be carried by a same linkage group. These analyses allowed the identification of 93 QTLs, most of them never described in the literature. In details, 69 QTLs were identified by single-QTL analysis and 24 through multi-QTL, illustrating the efficiency of this strategy. An important criteria for a possible marker assisted selection is to identify markers as close as possible from the causal mutations ; using a genetic map with 1412 markers has permitted to identify QTLs with interval localizations reduced to 14cM in average compared to the 32cM observed when using only the 127 microsatellites.