mei-W68^L1/mei-W68¹ female meioses exhibit crossover frequency reduction along chromosome 2, as compared to wild type.

mei-W68^L1/mei-W68^L1 and mei-W68^L1/mei-W68^Z4472 female meioses exhibit crossover frequency reduction in some, but not all, regions of chromosome 3, as compared to wild type.

Crossing over is reduced to about 50% of wild-type levels in homozygous and mei-W68^L1/mei-W68¹ females. mei-W68^L1 is recessive to wild type when nondisjunction frequencies are examined but has dominant effects on crossing over. Homozygous and mei-W68^L1/mei-W68¹ females show normal dynamics of germ-line mitotic divisions. The dynamics of entry into meiosis or exit of the losing pro-oocyte is also normal. The synaptonemal complex appears to be of normal morphology in homozygous females and appears to be between homologs. Late recombination nodules are present, while early recombination nodules appear to be missing. A novel structure ("noodle"), that resembles recombination nodules (RNs) in being adjacent to the central region of the synaptonemal complex, is seen. Noodles are smaller than RNs and are also less dense. The number of noodles increases up to the time cytoplasmic flow begins, and then significant numbers disappear once cytoplasmic flow begins.

Mutants show 3.6% X chromosome nondisjunction.

Reduces exchange to approximately 60% of control levels and also alters the distribution of residual exchanges.