sub1794 show allele specific interactions with alleles of ncd. sub1794/+, ncdD/+ transheterozygotes show a high frequency of non-disjunction, whereas either mutation alone is completely recessive. sub1794/+, ncd1/+ transheterozygotes do not show this effect. Df(2R)PC4/+, ncdD/+ shows less nondisjunction than sub1794/+, ncdD/+. sub1794 show a less strong, but still significant, interaction with nod4 than with ncdD. Stage 14 oocytes of sub1794/+, ncdD/+ show a defect in spindle pole formation - most often spindles are either monopolar or tripolar, karyosome may be split, spindles broken or misshapen such that they fray, or do not taper at the poles. Double mutants of sub1794 with ncd1 show no greater degree of oocyte spindle pole abnormality that those of ncd1 mutants alone - the effects of the two mutants are simply additive.