|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/1999
Publication Date: N/A
Technical Abstract: Identification of genes for reproduction traits in pigs could be useful for marker assisted selection and be of interest to producers in the future. This project was conducted to identify QTL for reproduction on chromosome 6 in swine. A population of 428 gilts was developed as an F2 cross of a line selected for 10 generations for increased ovulation rate and embryonic survival and a control line. Line differences were 6.7 ova, 3.3 fetuses a 50 days of gestation, and 3.1 pigs at birth. Ten F1 boars and 51 F1 gilts were used to produce F2 gilts. Traits analyzed included ovulation rate and number of nipples (n=428), age at puberty (n=295), and total born, number born alive, number of stillborn, and number of mummified pigs per litter (n=362). Six microsatelite markers were used. They averaged 18.5 cM apart and had information content that ranged from 11.9% to 61.3%. The largest gap between markers was 42 cM. No markers from 91 cM to the end of the chromosome (approximately 161 cM) were used. An interval analysis was conducted using least squares to regress phenotype on marker genotype with LOD score as the test statistic. A permutation method was used to establish a chromosome significance level of P < .05 (LOD = 2.50). Significant evidence of a QTL (LOD = 2.77) located between the markers HAL and SW1059 (approximately 82 cM on USDA-MARC map) for number of mummies was found. The markers in this region were approximately 25-30% informative. Suggestive evidence of a possible QTL at approximately 86 cM (USDA-MARC map) for ovulation rate (LOD = 2.46) was also found. Further studies with more markers are needed to verify this result and to detemrine accurately the position of the QTL.