DIRECT DETERMINATION OF DAIRY CATTLE'S GENETIC MERIT

AN INDIRECT MARKER-TRAIT RELATIONSHIP OCCURS WHEN THE GENETIC MARKER IS LOCATED NEAR THE CONTROLLING GENE. BECAUSE THE MARK AND TRAIT ARE LINKED THROUGH ASSOCIATION, THE MARKER-TRAIT RELATIONSHIP BETWEEN TWO INDIVIDUALS MAY NOT BE THE SAME. A GENETIC MARKER HAS BEEN USED TO DETECT A SIGNIFICANCE GENE SUBSTITUTION EFFECT FOR MILKING ABILITY FOR BOVINE CHROMOSOME 23 IN ONE HOLSTEIN BULL. THE MARKER-TRAIT RELATIONSHIP HAS ALSO BEEN DETERMINED TO BE INDIRECT. THE RELATIONSHIP MAY BE THE SAME OR DIFFERENT FOR OTHER HOLSTEIN BULLS OR BULLS IN OTHER BREEDS. WE PROPOSE TO DETERMINE WHETHER MARKER LOCI FOR A SECOND ELITE HOLSTEIN SIRE AND AN ELITE JERSEY SIRE REVEALS CHROMOSOME SUSTITUTION EFFECTS ASSOCIATED WITH CHROMOSOME 23. AT LEAST 5 MARKER LOCI SPANNING 16 CM WILL BE USED TO DETECT RECOMBINATIONS AND TO IDENTIFY ANIMALS WITH INTACT HAPLOTYPES.