A HIGH-RESOLUTION MAP AROUND THE LOCUS OM ON MOUSE CHROMOSOME-11

The locus Om (ovum mutant) identified in the mouse strain DDK affects the viability of (DDK x non-DDK)F-1 preimplantation embryos. We previo usly located this locus on Chromosome (Chr) 11 close to Scya2 (Baldacc i et al. Mamm. Genome 2, 100-105, 1992). Here we report a high-resolut ion map of the region around Om based on a large number of backcross i ndividuals. The same region has been analyzed on the EUCIB backcross, and the two maps have been compared. The results define the proximal a nd distal boundaries for the Om mutation as Scya2 and D11Mit36 respect ively. The distance between these two markers is about 2 cM. These dat a should facilitate the positional cloning and molecular characterizat ion of Om.