Cytogenetical anchoring of sheep linkage map and syntenic groups using a sheep BAC library

In order to simultaneously integrate linkage and syntenic groups to the ovi ne chromosomal map, a sheep bacterial artificial chromosome (BAC) library w as screened with previously assigned microsatellites using a sheep-hamster hybrid panel and genetic linkage. Thirty-three BACs were obtained, fluoresc ently labelled and hybridised on sheep-goat hybrid metaphases (2n = 57). Th is study allowed us, (i), to anchor all linkage groups on sheep chromosomes , (ii), to give information on the probable position of the centromere on t he linkage map for the centromeric chromosomes, (iii), to contradict the pr evious orientation of the ovine X linkage group by the mapping of BMS1008 o n OARXq38. Concerning our somatic cell hybrid panel, this study resulted in the assignment of all the previously unassigned groups to ovine chromosome s and a complete characterisation of the hybrid panel. In addition, since h ybridisations were performed on a sheep-goat hybrid, new marker/anchoring p oints were added to the caprine cytogenetic map.