Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 16, 1999
Publication Date: N/A
Technical Abstract: Preliminary analysis of variance for quantitative trait loci affecting conformation traits using the grandaughter design and eight large US Holstein grandsire families revealed a strong association in two families between the predicted transmitting abilities for dairy form and marker genotypes for bovine chromosome 27 (BTA27). Tests of marker association from Family 8 (79 sons) indicated an association (P = 0.000021) with a microsatellite marker located near the telomere of bovine chromosome 27 (BTA27). An association (P = 0.00001) was also detected in Family 2 (165 sons) with a microsatellite marker located approximately 20 cM from the centromere of BTA27. Interval analysis performed using a permutation test and additional BTA27 marker genotypes generated from Family 8 yielded a chromosome wide significance for a dairy form QTL near the telomere of BTA27, while no evidence was found for an association with milk production traits in this family. Interval analysis of Family 2 is in progress. Gene found in the genomic fragments of conserved synteny between human chromosomes 4 and 8 and BTA27 are being used to develop additional informative markers to refine the QTL interval and identify potential candidate genes for dairy form. Even though the phenotypic scores for dairy form are based upon dairyness and body condition, we hypothesize that this QTL may be associated with fat metabolism. This hypothesis is supported by identification of similarly located QTL found in other cattle populations for marbling, milk fat yield, and milk fat percentage.