Imprecise excision of the progenitor insertion, resulting in a deletion.
FlyBase curator comment: The disease model used a hemizygous genotype of seaΔ24/Df.
Brain neuroblasts of homozygous and seaΔ24/Df(3R)Mx-1 larvae show defects in mitosis, with a high frequency of chromosome breaks. The mitotic index of the mutant cells is reduced approximately 3-fold in seaΔ24/Df(3R)Mx-1 larvae.
Brain neuroblasts of seaΔ24/seaEP3364 larvae show defects in mitosis, with a high frequency of chromosome breaks. Mutant cells with highly fragmented nuclei containing chromosome "splinters" are also seen.