ChickRH6: a chicken whole-genome radiation hybrid panel

As a first step towards the development of radiation hybrid maps, we have produced a radiation hybrid panel in the chicken by fusing female embryonic diploid fibroblasts irradiated at 6 000 rads with HPRT-deficient hamster Wg3hCl2 cells. Due to the low retention frequency of the chicken fragments, a high number of clones was produced from which the best ones were selected. Thus, 452 fusion clones were tested for retention frequencies with a panel of 46 markers. Based on these results, 103 clones with a mean marker retention of 23.8% were selected for large scale culture to produce DNA in sufficient quantities for the genotyping of numerous markers. Retention frequency was tested again with the same 46 markers and the 90 best clones, with a final mean retention frequency of 21.9%, were selected for the final panel. This panel will be a valuable resource for fine mapping of markers and genes in the chicken, and will also help in building BAC contigs.