Heritability of the maternal meiotic drive system linked to Om and high-resolution mapping of the Responder locus in mouse

Matings between (C57BL/6 X DDK)F-1 females and C57BL/6 males result in a si gnificant excess of offspring inheriting maternal DDK alleles in the centra l region of mouse chromosome 11 due to meiotic drive at the second meiotic division. We have shown previously that the locus subject to selection is i n the vicinity of D11Mit66, a marker closely linked to the Om locus that co ntrols the preimplantation embryolethal phenotype known as the "DDK syndrom e." We have also shown that observation of meiotic drive in this system dep ends upon tl-le genotype of the sire. Here we show that females that are he terozygous at Om retain the meiotic drive phenotype and define a 0.32-cM ca ndidate interval for the Responder locus in this drive system. In addition, analysis of the inheritance of alleles at Om among the offspring of F-1 in tercrosses indicates that the effect of the sire is determined by the sperm genotype at Om or a locus linked to Om.