DNA fingerprinting analysis of Booroola pedigrees: a search for linkage to the Booroola gene.

Seven minisatellite probes from a variety of sources were used to analyse 11 paternal half-sib families in which the Booroola gene was segregating. A total of 402 bands that showed segregation in the pedigrees were examined for linkage to the Booroola gene. None of the bands showed segregation with the Booroola gene. The most likely evidence for a linked band was produced by the HaRas HVR probe in Family 902 (θ=0.0; LOD 2.3). The conclusion, however, is that the minisatellite probes used in this study could not be used as markers for the Booroola gene. The study highlighted problems associated with the use of minisatellite probes in linkage studies in half-sib families. The complex banding patterns found on fingerprinting gels was a major source of scoring error. In a few cases both of the sire's alleles could be identified at a particular locus, but in most cases only one of the alleles could be identified. For the most part, the bands had to be treated as dominant alleles. The contribution of dam alleles to the banding pattern could only be estimated. There was an indication that minisatellite loci in sheep are clustered in particular regions of the sheep genome as the rate at which bands segregated with each other was higher than one would expect from loci randomly distributed throughout the genome.