Assignment of 280 swine genomic inserts including 31 microsatellites from BAC clones to the swine RH map (IMpRH map)

A precise genetic map containing anonymous markers and genes is indispensable for the efficient selection of candidate gene(s) responsible for quantitative trait loci (QTL) traits. For this purpose, a first version of a radiation hybrid cell (RH) map has been constructed by using the INRA-University of Minnesota RH panel for 757 markers (IMpRH) (Hawken et al. 1999, Mamm. Genome 10: 824--830). In this study, 280 swine genomic fragments in BAC clones were assigned to the IMpRH map; 255 BAC clones were successfully linked to first-generation linkage groups (LOD > 4.8). The remaining 25 clones could not be mapped, because their lod-scores to the closest markers in the first generation map were less than 4.8. In addition, 16 BAC clones, mapped to swine Chromosome (Chr) 1 by IMpRH mapping, were subjected to isolation of microsatellites (MSs). Thirty-one MSs were isolated from 15 BAC clones, and 24 of 31 (77%) MSs derived from 14 clones were found to be polymorphic. We also mapped both termini of 12 BAC clones to the IMpRH map, in order to measure resolution of the IMpRH map; the resolution was found to range from 8 kb/centiRay to more than 126 kb/centiRay depending on the region.