Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2000
Publication Date: N/A
Interpretive Summary: These results provide more information about the genetics of growth rate and fat accretion in swine. The two regions which affected growth rate (chromosomes 1 and 7) have previously been identified as affecting backfat depth, and trimmed retail product yield in the same population. By increasing the knowledge of the traits these QTL affect, scientists will be better equipped to select positional candidate genes to study. These locations need to be assessed in commercial populations of swine to determine their utility in the swine industry.
Technical Abstract: A search for genomic regions affecting birth characters and accretion of weight and fat was conducted in a Meishan-White Composite reciprocal backcrossed resource population. Birth traits analyzed (N=750) were vigor score (VGS), number of functional teats (NFT), and birth weight (WT0). Subsequent measures on gilts and barrows (N=706) analyzed were weaning or 4 wk weight (WT4), 8 wk weight (WT8), average daily gain from 8 to 18 wk of age (EDG), average daily gain from 18 to 26 wk of age (LDG), 26 wk weight (WT26), backfat measures at 14 and 26 (N=599) wk of age over the first rib, last rib, and last lumbar vertebrae (FR14, FR26, LR14, LR26, LL14, and LL26, respectively). Feed intake and growth on 92 individually penned barrows was also analyzed. A genomic scan was conducted with microsatellite markers spaced at approximately 20 cM intervals, a least squares regression interval analysis was implemented and significance values were converted to genome-wide standards. No associations with birth characters were detected except for NFT where one significant and two suggestive regions were identified on chromosomes (SSC) 10, 1, and 3, respectively. Early growth was affected by a region on SSC 1 as evidenced by associations with WT4, WT8, and EDG. Other regions detected for early growth rate were on SSC 2, 12, and X. LDG was affected by chromosomal regions on SSC 6 and 7. All measures of backfat were affected by regions on SSC 1 and X, while SSC 7 consistently affected backfat measures recorded at 26 wk of age. Suggestive evidence for QTL affecting backfat at 14 wk of age were also detected on SSC 2, 6, 8, and 9. These results have improved our knowledge about the genetics of growth rate and fat accretion at the molecular level in swine.