|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/1999
Publication Date: N/A
Technical Abstract: The objective was to identify chromosomal regions containing QTL affecting reproduction. A three-generation resource population was developed by crossing low indexing animals from a control line (C) with high indexing animals of a line selected for increased index of ovulation rate and embryonic survival (I). Differences between I and C at Generation 10 were 6.7 ova and 3.3 fetuses at 50 d of gestation and 3.1 fully formed pigs and 1.6 live pigs at birth. Phenotype for F2 females were ovulation rate (n = 428), age at puberty (n = 295), litter size (n = 362) and number of teats (n = 428). Data included number of fully formed, live, stillborn, and mummified pigs. Grandparents, F1, and F2 animals were genotyped for 96 microsatellite markers distributed across all chromosomes except 9, 18, and X. Calculation of LOD scores was by least squares including fixed effects of litter and replicate. Suggestive evidence was previously reported for QTL influencing age at puberty on chromosome 1 (16 cM, LOD = 3.92 and 129 cM, LOD = 3.12) and chromosome 8 (120 cM, LOD = 3.74) and for number of stillborns on chromosome 13 (104 cM, LOD = 4.04) using the USDA-MARC linkage map as reference. In this investigation suggestive evidence was found for a QTL affecting number of stillborns on chromosome 10 (65 cM, LOD = 3.80). Evidence of a QTL on chromosome 5 affecting number of mummies was below the suggestive level of significance (134 cM, LOD = 2.91). All traits for which QTL were detected are lowly to moderately heritable and expressed only in females. Response to selection for these traits might be enhanced by marker-assisted selection (MAS). Age at puberty, the most labor intensive trait to measure, may benefit most from MAS.