Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2004
Publication Date: 7/26/2004
Citation: Mousel, M.R., Rohrer, G.A., Leymaster, K.A., Christenson, R.K. 2004. Validation of QTLs in a swine population selected for ovulation rate. Journal of Animal Science 82(Supplement 1):452.
Technical Abstract: Variations in allele frequency of a four-breed, white composite population of swine selected for ovulation rate (OR) were evaluated. Animals were selected for 11 generations for increased OR and compared to unselected controls (CO). The selection line had an increase of 3.0 corpora lutea and an increase of 0.3 pigs in total litter size as compared to controls. DNA was collected from 146 CO and 156 OR gilts and boars at generations 10 and 11. A QTL analysis for OR identified loci on chromosomes 3, 8, and 10 in a Meishan-White composite population. Three microsatellite markers were selected for chromosomes 3 (17-42 cM) and 10 (85-96 cM) and six for chromosome 8 (1-13 cM) for utilization with selected and control lines. Allele frequencies of markers contained within QTL peaks were analyzed by logistic regression to ascertain any difference in allele frequency due to selection. All markers on chromosome 3 had significant (P<0.01) changes between lines in allele frequency. Odds ratio of the most significant marker (P<0.0001), SW2429 contained 7 distinct alleles, the 125 base allele was 530.2 times more likely to be present in homozygous OR animals than CO. Chromosome 8 had 3 of 6 markers with significant (P<0.02) changes in allele frequency. The marker SW2651, which contained 3 alleles, was most significant (P<0.0001) with an odds ratio of 2.6 for the 100 base allele in homozygous OR animals. Significant (P<0.01) changes in allele frequency were found on chromosome 10 with all markers. An odds ratio of 7.3 was calculated for the 107 base allele in homozygous OR animals for the most significant (P<0.0001) marker SWR1829 which had 8 alleles. Selection for OR has changed the allele frequency of markers from the three QTL regions studied. The QTL discovered in a Meishan cross population are likely segregating in occidental germplasm. The selection line will be useful to identify causative genes and genetic markers for use in the industry.