Imprecise excision of the P{GT1} element resulting in deletion of nucleotides 93-278 of the Umbrea sequence.
polar body nucleus
In 20% of eggs produced by Umbrea36-5/Df(2L)dp-h25 females, polar-body chromosomes are dispersed, while only 2.3% of eggs from Umbrea36-5/+ females display this defect.