Random chromosome segregation without meiotic arrest in both male and female meiocytes of a dmc1 mutant of Arabidopsis

In yeast, the DMC1 gene is required for interhomolog recombination, which i s an essential step for bivalent formation and the correct partition of chr omosomes during meiosis I. By using a reverse genetics approach, we were ab le to identify a T-DNA insertion in AtDMC1, the Arabidopsis homolog of DMC1 . Homozygotes for the AtDMC1 insertion failed to express AtDMC1, and their residual fertility was 1.5% that of the wild type. Complete fertility was r estored in mutant plants when a wild-type copy of the AtDMC1 gene was reint roduced. Cytogenetical analysis points to a correlation of the sterility ph enotype with severely disturbed chromosome behavior during both male and fe male meiosis. In this study, our data demonstrate that AtDMC1 function is c rucial for meiosis in Arabidopsis. However, meiosis can be completed in the Arabidopsis dmc1 mutant, which is not the case for mouse or some yeast mut ants.