A comparative linkage and physical map of bovine chromosome 24 with human chromosome 18

Polymorphic microsatellites have been developed in the vicinity of nine gen es on bovine chromosome (BTA) 24, all orthologous to genes on human chromos ome (HSA) 18. The microsatellites have been isolated from bacterial and yea st artificial chromosome clones containing the genes. A linkage map was dev eloped including these polymorphic markers and four anonymous, published mi crosatellites. Yeast artificial chromosomes containing six of these genes h ave also been mapped using fluorescent in situ hybridization (FISH), thereb y tying the linkage map together with the physical map of BTA24. Comparing gene location on HSA18 and BTA24 identifies four regions of conserved gene order, each containing at least two genes. These genes identify six regions of conserved order between human and mouse, two more than in the human-bov ine comparison. The breakpoints between regions of conserved order for huma n-bovine are also breakpoints in the human-mouse comparison. The centromere identifies a fifth conserved region if the BTA24 centromere is orthologous with the HSA18 centromere.