Genotyping new BXD recombinant inbred mouse strains and comparison of BXD and consensus maps

摘要: Nine additional BXD recombinant inbred (RI) strains have been developed from the F2 cross of C57BL/6J and DBA/2J mouse strains. A tenth line stopped breeding in F12 generation. F20 generation pairs nine surviving an pair extinct were genotyped at 319 genetic markers (primarily microsatellites) spanning most genome. Where typing data lacking, established set 26 also these same loci. The availability enhances value RI for analysis complex phenotypic traits. proportion loci still segregating was found to closely approximate expectation, suggesting that selection favoring retention heterozygosity is not a strong factor. However, number crossovers between adjacent frequently less than predicted consensus map distances. significant deficiency recombinants observed on Chrs 3, 4, 14, X. On Chr estimated cumulative distance proximal distal only 30.2 cM, compared with 60.0 cM map. X Chr, distances 38.8 69.5 respectively. Over all chromosomes, 14.5% shorter It suggested some maps are inflated. Alternatively, genotypes could be selected against during inbreeding owing allelic interactions affecting fitness. latter interpretation implies relatively intrachromosomal epistasis common.