Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 1998
Publication Date: N/A
Preliminary analysis of quantitative trait loci (QTL) affecting conformation traits in seven large US Holstein grandsire families has been completed. Predicted transmitting abilities from Holstein Association USA were analyzed for association with marker genotypes using analysis of variance (ANOVA). Strong evidence (P = 0.000021) was found for a QTL associated with marker BM203 on chromosome 27 for dairy form in a single grandsire family. This grandsire had 79 sons represented in the dairy bull DNA repository (DBDR). The BM203 marker is the farthest marker from the centromere placed on the USDA Meat Animal Research Center (MARC) cattle linkage map for chromosome 27. Six additional microsatellite markers on the MARC map were genotyped for animals in this family. The grandsire was not heterozygous for two of these markers. Number of observations (i.e., sons) ranged from 32 to 51. Location of new markers were from 5.9 to 45.8 cM from BM203. Statistical significance of the new markers ranged from .0004 to .0207; markers at 8.7 and 11.4 cM away from BM203 were significant at P =.0009 and P = .0006, respectively. High levels of statistical significance provide further evidence of a QTL on chromosome 27. A more exact genetic location of the QTL is desired and will be the subject of further study.