A MEDIUM-DENSITY GENETIC-LINKAGE MAP OF THE BOVINE GENOME

A cattle genetic linkage map was constructed which covers more than 95 percent of the bovine genome at medium density. Seven hundred and for ty six DNA polymorphisms were genotyped in cattle families which compr ise 347 individuals in full sibling pedigrees. Seven hundred and three of the loci are linked to at least one other locus. All linkage group s are assigned to chromosomes, and all are orientated with regards to the centromere. There is little overall difference in the lengths of t he bull and cow linkage maps although there are individual differences between maps of chromosomes. One hundred and sixty polymorphisms are in or near genes, and the resultant genome-wide comparative analyses i ndicate that while there is greater conservation of synteny between ca ttle and humans compared with mice, the conservation of gene order bet ween cattle and humans is much less than would be expected from the co nservation of synteny. This map provides a basis for high-resolution m apping of the bovine genome with physical resources such as Yeast and Bacterial Artificial Chromosomes as well as providing the underpinning for the interpolation of information from the Human Genome Project.