Analysis of meiosis-defective mutations in XXXX by physical monitoring of recombination.

@entity12248 @entity11024 @entity374 @entity38877 @entity375 @entity9871
We have developed a method by which the extent of physical exchange of DNA molecules can be determined throughout meiosis in the @entity375 @entity375 . We have used this technique to analyze the effect of five meiosis-defective mutations ( @entity11024 , @entity12248 , @entity9871 , @entity38877 and @entity374 ) on the physical exchange of DNA molecules. In the same experiments, we have also measured other meiotic parameters, such as premeiotic DNA synthesis, commitment to intragenic recombination, haploidization, ascus formation, and viability. @entity12248 and @entity374 diploids make an undetectable amount of physically recombined DNA and less than 1% of wild-type levels of viable intragenic recombinants. In contrast, diploids homozygous for @entity9871 , @entity11024 or @entity38877 all yield significant amounts of novel restriction fragments which arise by recombination. @entity38877 diploids make nearly wild-type levels of the recombined restriction fragments, although they produce less than 10% of the wild-type levels of viable intragenic recombinants. @entity9871 strains are also capable of a significant (33%) amount of exchange of DNA molecules, but make less than 1% of wild-type levels of viable intragenic recombinants. @entity11024 diploids are also capable of undergoing a high level of exchange, as measured by the appearance of the recombined restriction fragment. In addition, @entity11024 diploids show an unusual allele- or locus-specific variability in the level of viable intragenic recombinants produced. Although @entity11024 diploids produce no viable spores, they are able to complete a significant amount of haploidization upon return to vegetative growth conditions.
