ph-plac homozygous females have egg chambers with abnormal numbers of germ cells. Egg chambers in these mutants with more than 16 germ cells (23% ovarioles contain at least one of these) sometimes contain groups of nurse cells with differing degrees of polyploidy, but all contain multiple oocytes. When an egg chamber contains fewer than 15 nurse cells (5.6%), one of the adjacent chambers contains the complementary number of nurse cells or degenerating nurse cells. Whether follicles contain more or fewer than the normal number of germline cells, there are always two groups of polar cells, one at each extremity, anterior and posterior, but these groups often contain extra polar cells. Apposed eggs chambers not separated by an interfollicular stalk are also present in these mutants. Where stalks are present they are abnormal - containing 10-50 cells in 2-3 lines rather than five to seven cells organized in a single line as in wild-type. This excess of polar and stalk cells is not due to any proliferation of these cells after stage 1, and so must be due to processes occurring in the germarium. Germaria in ph-plac homozygous females display a variety of phenotypes: delayed budding of the emerging egg chambers; disorganized arrangement of encapsulated cysts; splitting of germline cysts and envelopment of fewer than 16 germline cells; an absence of prefollicular cell migration between adjacent germline cysts associated with an accumulation of several mature cysts in region 3 of the germarium (in these cases, prefollicular cell invagination can be seen anteriorly, probably prefiguring to budding of a multicyst egg chamber). In the most extreme cases there is no clear boundary between germarium and vitellarium. The number of mitotic somatic cells in regions 2b and 3 of the germarium is significantly lower for ph-plac homozygous females compared to ph-plac/+ control sisters.
Transheterozygotes with a null ph-p allele or a deficiency of ph-p cause lethality.
Mild homeotic transformation.