Embryos from homozygous females develop nearly normally through the 13th mitosis, but there is no membrane invagination or nuclear elongation during interphase 14. A few minutes after entry into interphase 14 the blastoderm nuclei are swept about, causing an uneven, convoluted distribution. This abnormal movement of the nuclei can be prevented by injection of the embryos with colcemid as they enter interphase 14.

Pole cells from defective mat(3)1¹/+ embryos derived from homozygous females transplanted into wild-type embryos form fertile gametes in both sexes. Pole cells from defective mat(3)1¹ homozygous embryos derived from homozygous females transplanted into wild-type embryos form fertile gametes only in males.

Homozygous embryos derived from heterozygous females are morphologically normal and viable. Approximately 55% of heterozygous and homozygous embryos derived from homozygous females appear to progress normally through the syncytial blastoderm stage, except for occasional asynchrony during the last three syncytial divisions and a reduction in the number of pole cells from the normal 35 cells to about 20 cells. Major abnormalities become evident during the transition from syncytial to cellular blastoderm; none of the blastoderm nuclei elongate and no blastoderm cells are formed. Instead, the nuclei migrate away from the surface and subsequently aggregate and degenerate. Movements similar to early gastrulation in normal embryos occur between 3 and 4 hours after fertilisation; the blastoderm layer containing the nuclei thickens along the ventral midline, and in the posterior region this layer moves with the pole cells in an anterior direction, usually along the dorsal surface, about 1/4 of the length of the egg. Several hours later the pole cells are no longer visible, and have probably degenerated. 18% of eggs laid by homozygous females do not develop, or stop developing after producing only a few cleavage nuclei (22%), the remainder (5%) produce an incomplete syncytial blastoderm covering the anterior and middle regions of the egg but not the posterior region.