Homozygotes and transheterozygotes in combination with mei-9a, mei-9b or mei-9A1 have normal frequencies of X chromosome non-disjunction. Homozygous females show a normal rate of recombination on the second chromosome.
Methyl methanesulfonate sensitive, exposure causes lethality. Low frequency of nondisjunction.
Transposase induced reversion demonstrates a P-element insertion is responsible for the mutant phenotype.