An ordered comparative map of the cattle and human genomes

A cattle-human whole-genome comparative map was constructed using parallel radiation hybrid (RH) mapping in conjunction with EST sequencing, database mining for unmapped cattle genes, and a predictive bioinformatics approach (COMPASS) for targeting specific homologous regions. A total of 768 genes w ere placed on the RH map in addition to 319 microsatellites used as anchor markers. Of these, 638 had human orthologs with mapping data, thus permitti ng construction of an ordered comparative map. The large number of ordered loci revealed equal to or greater than 105 conserved segments between the t wo genomes. The comparative map suggests that 41 translocation events, a mi nimum of 54 internal rearrangements, and repositioning of all but one centr omere can account for the observed organizations of the cattle and human ge nomes. In addition, the COMPASS in silico mapping tool was shown to be 95% accurate in its ability to predict cattle chromosome location from random s equence data, demonstrating this tool to be valuable for efficient targetin g of specific regions for detailed mapping. The comparative map generated w ill be a cornerstone for elucidating mammalian chromosome phylogeny and the identification of genes of agricultural importance. "Ought we, for instance, to begin by discussing each separate species-in vi rtue of some common element of their nature, and proceed from this as a bas is for the consideration of them separately?" from Aristotle, On the Ports of Animals, 350 B.C.E.