Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 3, 2006
Publication Date: January 2, 2007
Citation: Nonneman, D.J., Kuehn, L.A., Rohrer, G.A. 2007. Fine-mapping QTL for nipple number in the pig [abstract]. Plant and Animal Genome XV Conference. Poster No. P579. Technical Abstract: The number of functional nipples is an important trait in pigs. Selection for increased litter size has resulted in number of live born piglets exceeding the number of functional nipples in prolific sows. Quantitative trait loci (QTL) for nipple number have been consistently found in various populations on several pig chromosomes. To refine the position and confirm the presence of these QTL, we evaluated 65 single nucleotide polymorphisms (SNP) located within the confidence intervals of QTL for nipple number on chromosomes 1, 3, 7, 8 and 10. We genotyped animals from the F8 and F10 generations of the USMARC Meishan-cross population and tested for significant associations with SNP marker genotypes. Genotype probabilities were calculated for 1144 animals using an extended version of GenoProb and associations between nipple number and genotypes were performed with MTDFREML using an animal model. Significant associations (p<0.05) were detected on chromosomes 3, 8 and 10, while no associations were found between SNP genotypes and nipple number on chromosomes 1 or 7. The effects were either additive (SSC10) or overdominant and ranged from 0.3 – 1.0 nipples for alternate homozygotes. Some significant SNPs on chromosomes 3 and 10 reside in positional candidate genes (PREB and BAMBI, respectively). Three distinct regions were associated with nipple number on chromosome 10. These markers are being tested in commercial pig populations and may potentially be useful in breeding programs to select for increased number of nipples in maternal lines.