Abstract
A genome-wide scan was performed in Large White and French Landrace pig populations in order to identify QTL affecting reproduction and production traits. The experiment was based on a granddaughter design, including five Large White and three French Landrace half-sib families identified in the French porcine national database. A total of 239 animals (166 sons and 73 daughters of the eight male founders) distributed in eight families were genotyped for 144 microsatellite markers. The design included 51 262 animals recorded for production traits, and 53 205 litter size records were considered. Three production and three reproduction traits were analysed: average backfat thickness (US_M) and live weight (LWGT) at the end of the on-farm test, age of candidates adjusted at 100 kg live weight, total number of piglets born per litter, and numbers of stillborn (STILLp) and born alive (LIVp) piglets per litter. Ten QTL with medium to large effects were detected at a chromosome-wide significance level of 5% affecting traits US_M (on SSC2, SSC3 and SSC17), LWGT (on SSC4), STILLp (on SSC6, SSC11 and SSC14) and LIVp (on SSC7, SSC16 and SSC18). The number of heterozygous male founders varied from 1 to 3 depending on the QTL.
Highlights
Three strategies have been applied in livestock for quantitative trait loci (QTL) mapping
Exploiting existing familial structures in commercial populations is an approach of choice for QTL mapping, in particular for reproduction traits, since: (1) it avoids the implementation of a long and expensive experimental design; (2) the detected QTL are immediate candidates for marker assisted selection
Mapping QTL for phenotypes that are difficult or expensive to measure on a large number of animals is excluded, whereas these are precisely the traits whose selection is likely to show the largest gains from the use of markers
Summary
Three strategies have been applied in livestock for quantitative trait loci (QTL) mapping. On the use of experimental intercrosses between distant breeds, for example Large White and Meishan [5], wild boar and Large White [1], or Berkshire and Yorkshire [25]. This approach is powerful, since all F1 animals are expected to be heterozygous for many markers and many QTL. This approach has resulted in mapping hundreds of loci in the pig over the last decade (see PigQTLdb [17]). The practical use of these results in pig breeding programs has been limited so far
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
