Mutants show a significant amount of chromatid stretching during mitotic anaphase compared to wild type.
Embryos derived from germline clones usually arrest prior to blastoderm formation but manage to form small patches of cuticle. Brain cells of mutant larvae show defects in heterochromatin organisation. In metaphase figures, the sister chromatids of the major autosomes and of the X chromosome are aligned parallel to each other, instead of the wild-type X- and V- shaped arrangements. The Y and 4th chromosomes are resolved into two distinct sister chromatids, in contrast to wild type. The sister chromatids of all mutant chromosomes are not completely separated but are instead connected by a thread located in the centromeric region. The mitotic index is normal. wapl2/In(1)FM7 females show a significant increase in X chromosome nondisjunction compared to control +/In(1)FM7 females. wapl2/+ females show the same level of X chromosome nondisjunction as control +/+ females.
Transmission rate of Dp(1;f)J21A through females to progeny is 28%, wapl mutation has no effect on transmission.
Lethality occurs during larval and pupal stages. Phenotype of homozygous germ line clones is maternal effect lethal.
L3 larval/pupal boundary lethal exhibit small disk phenotype; homozygous germ-line clones produce zygotes that arrest in preblastoderm stage.