MAPPING GENOMIC REGIONS ASSOCIATED WITH GROWTH-RATE IN PIGS

The objective of this study was to identify genomic regions associated with postweaning average daily gain (ADG) in swine. Two families were produced using sires obtained from the cross of Lines divergently sel ected for high and low growth rate. Sires were mated to 29 unrelated d ams that produced 124 and 115 offspring. Average daily gain was record ed for every individual; mean ADG was .593 +/- .007 kg/d and .619 +/- .009 kg/d in the two families. Selective genotyping was performed as a prescreening procedure to identify genomic regions potentially associ ated with ADG. A total of 75 genetic markers were used between both fa milies. Markers identified as nominally significant (P < .05) in an in dividual marker analysis were subsequently typed in all individuals. M arkers still nominally significant (P < .05) after analysis with the c omplete family were then reevaluated together with flanking markers in an interval mapping analysis. A single region on chromosome 3, flanke d by markers Sw2429 and Sw251, for the second family had a logarithm o f the odds score of 2.9, which is suggestive of linkage with a quantit ative trait locus for ADG. Differences were .033 +/- .009 kg/d between individuals inheriting alternative paternal alleles for Sw251, which was the most significant marker.