Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/1999
Publication Date: N/A
Technical Abstract: A scan for QTL affecting postweaning average daily gain (ADG) in a resource family produced from divergent lines of pigs selected 10 generations for either fast (F) or slow (S) ADG. The scan revealed several chromosomal regions containing putative QTL effects, the most significant of which was located on chromosome 3 and accounted for 5% of the phenotypic variation in nADG. The objective of the present study was to type additional markers on this region of chromosome 3 in the same resource family. Two F1 (F x S) sires were mated to a total of 29 unrelated dams to produce two half-sib families (124 and 115 offspring from sires 1 and 2, respectively) in which ADG from 28 days of age to 105 kg body weight was measured. In the initial genome scan, a microsatellite marker on chromosome 3 (Sw251) was significantly associated with ADG in the family of sire 2. Subsequent interval analysis suggested that a region bracketed by microsatellite markers Sw2429 and Sw251 contained a QTL for ADG. In the present analysis, additional microsatellite markers within the region were for selected for genotyping to more precisely determine the location of the putative QTL. Of the markers screened, only two (Sw72 and S0206) were informative for sire 2. All progeny of sire 2 were genotyped for Sw72 and S0206 alleles. For each marker, ADG was regressed on the probability of receiving a designated allele from the sire. Regressions of ADG on inheritance of Sw72 and S0206 alleles were similar in significance (P < .01) and magnitude (approximately .03 to .04 kg/d in ADG) to the regression on Sw251. These results support the hypothesis that a QTL for ADG is contained in this chromosomal region. Genotypes for these microsatellites will be added to an interval analysis to obtain a more precise location of the QTL.