The progeny of a cross between homozygous (D.melanogaster) females and D.melanogaster males show loss of X chromosomes, resulting in X/O clones which can occur on the head, thorax or abdomen. The progeny of a cross between homozygous (D.melanogaster) females and D.simulans males show a higher frequency of X/O clones (80%), which are only found on the abdomen. These hybrid clones are smaller than those resulting from the cross between homozygous mit1 (D.melanogaster) females and D.melanogaster males. 9% of hybrids from a cross between homozygous mit1 (D.melanogaster) females and D.mauritiana males have X/O clones, all of which are abdominal. 68% of hybrids from a cross between homozygous mit1 (D.melanogaster) females and D.sechellia males have X/O clones, most of which are abdominal.
Hemizygous male larvae are not sensitive to HN2 and MMS.
Gynandromorphs and haplo-4 mosaics are produced in the progeny of homozygous females (mit1 acts maternally). The mosaics result from somatic loss rather than from somatic nondisjunction. Mosaic loss of maternal or paternal X or 4th chromosomes can occur. The probability of loss of either the maternal or paternal X chromosome is equal. Relative frequencies of observed loss of maternal and paternal X chromosomes depend on the markers carried rather than the parental origin of the X chromosomes. The frequency of double mosaic gynandromorphs suggests that each loss event is independent. The ring X chromosome R(1)2 is lost as readily as a rod X chromosome, but neither attached XY chromosomes nor Y chromosomes are frequently eliminated by mit1. Chromosome loss usually occurs between the third and fourth mitotic divisions in the zygote, which produces mosaic patches of intermediate size. There is no effect on meiotic X chromosome disjunction in females. Hemizygous males do not produce mosaic progeny.
Modifiers tend to accumulate in mit1 stocks, which reduce the frequency of mosaics. mit1-induced gynandromorphs are useful in constructing morphogenetic fate maps.