A methodological approach for the construction of a radiation hybrid map of bovine chromosome 5

A bovine 5,000 rad WG-RH panel was used to construct an RH map of bovine chromosome 5 (BTA5). Twenty-one microsatellites and thirteen genes were scored in the panel using PAGE and radioactive labeling. Marker retention ranged from 8.9%-25.8% and averaged 17.8%. Pairwise locus analysis placed all markers in a single syntenic group with a LOD support of 4.0. At a LOD support of 8.0, a centromeric group of 23 syntenic markers was formed. Telomeric groups of 11 and 9 markers were assembled with a LOD support of 6.0 and 8.0, respectively. All markers were ordered by maximum likelihood methods using the program RHMAP. Only 13 markers were ordered with a LOD support of at least 3.0, while 25 and 29 markers were ordered with a support of at least 2.0 and 1.0, respectively. Total length of the comprehensive RH map was 435.9 cR5,000, with an average marker separation of 12.8 cR5,000. The largest gaps in the map were 55.0 and 30.4 cR5,000 in length. The locus orders of markers common to both the RH map and the USDA-MARC linkage map were identical. The relationship between the RH and linkage maps was calculated to be 3.74 cR5,000/cM