High-frequency meiotic gene conversion between repeated genes on nonhomologous chromosomes in yeast.

We have used a genetic system that allows detection of meiotic recombination events between repeated sequences on nonhomologous chromosomes in the yeast Saccharomyces cerevisiae. We have found that recombination between these sequences occurs at a frequency of about 0.5%, and the events observed were nonreciprocal (gene conversions). Surprisingly, the frequency of conversion between the repeated genes on nonhomologous chromosomes observed in this study is similar to that observed between allelic genes. This result is discussed in connection with the role of the synaptonemal complex in meiotic recombination and with the relationship between reciprocal and nonreciprocal recombination.