Produces 32% XO male self-progeny; nondisjunction is correlated with a high frequency of achiasmate X chromosomes in oocyte nuclei, and a reduced frequency of X chromosome crossovers. meDf5 disrupts the function of the cis-acting X chromosome meiotic pairing center. meDf5/+ heterozygotes produce 4-6% XO progeny, so the presence of meDf5 can be followed in heterozygotes by this weak Him phenotype.

Hets are WT and segregate WT, dead eggs, and larval lethals (eDf24 homozygotes). eDf24 = let(e2000).