Random mutagenesis of proximal mouse chromosome 5 uncovers predominantly embryonic lethal mutations

The lethal genes include embryonic lethal mutations only, not those causing post- or perinatal lethality. The 423 gametes reported in the t complex study represent a composite of multiple breeding paradigms covering the region spanned by T proximally and either tufted (tf) or H-2 distally. The albino target region, and corresponding gene count, corresponds to the interval between D7Mit350 and D7Mit351 (D. Johnson, pers. comm.). The size of the target regions and gene numbers are taken from Emsembl as of February, 2005. The “Lethal compl. groups” category is the number of complementation groups recovered, where known. The number of lethal mutations that were not recovered as mutants was estimated based on a per-locus mutation rate of 1/1500/gamete and calculated as [(1499/1500)^P] [L/1-(1499/1500)^P] where P = # gametes; L = # complementation groups. This was added to the number of complementation groups to obtain the “Est. # lethal genes.” The “% lethal genes” is calculated as the “Est. # lethal genes”/“# genes”)*100. The references for the albino, t complex, and Trp53—Wnt3 studies are Rinchik and Carpenter (1999), Shedlovsky et al. (1988), and Kile et al. (2003), respectively. The latter study uncovered 55 lethal mutations in total, representing 51 complementation groups (K. Hentges and M. Justice, pers. comm.), 30-32 of which acted embryonically.