DNA MARKER-ASSISTED SELECTION OF THE POLLED CONDITION IN CHAROLAIS CATTLE

Five Charolais families known to segregate for both homed and polled w ere selected and tested for linkage analysis by use of microsatellites and karyotyping for Robertsonian translocation 1;29. No recombinants were found between any of these markers and the polled phenotype or ea ch other. When statistical analysis was performed, the logarithm of th e odds (LOD) indicated that there was 100% linkage occurring between t he markers and the phenotype (p < 0.001). These microsatellite markers , TGLA49 and BM6438, can be assumed to be very close to the actual gen e that determines the polled phenotype. Another linked marker, SOD1, w as physically mapped, which places all of these markers within 1q12-14 , very near the centromere of Chromosome (Chr) 1. A homozygous polled cow was identified in this study by following the alleles at both mark ers and the phenotypes in her family.