Polytene chromosomes normal.
The S1 mutation overcomes the suppression of the Gl1 rough eye phenotype by Dhc64C8-1 or Dhc64C77, so that triple heterozygotes have an enhanced rough eye phenotype compared to Gl1 single heterozygotes.
Oogenesis arrests at the germarial stage in S1 aretPD/Df(2L)esc-P2-0 females. The ovarioles fail to bud off into individual egg chambers and instead, multiple undifferentiated germ cells appear in the severely truncated ovarioles. Oogenesis arrests at stage 6/7 in S1 aretPA/aretPD females. Oogenesis arrests at about stage 3 in S1 aretPD/aretQB females and no oocyte is specified. The oogenesis defects of S1 aretPD/Df(2L)esc-P2-0 females are partially suppressed by one copy of Df(3R)M-Kx1; egg chambers bud off from the germarium, although they are abnormal - each egg chamber has more than the normal number of 16 germ cells and no oocyte is specified. Df(3R)Dl-BX12 dominantly alters the ovary phenotype of S1 aretPD/Df(2L)esc-P2-0 females; the germarium is greatly expanded to produce a large volume of germ cells surrounded by a layer of follicle cells. The oogenesis arrest phenotype of S1 aretPD/Df(2L)esc-P2-0 females is suppressed by Df(3R)mbc-R1/+.
The phenotype is dominantly enhanced by ast1 : double heterozygotes have extremely small, diamond-shaped eyes in which many of the facets are fused and the remainder are irregular in size and distribution. The phenotype is dominantly enhanced by E(S)1. Lethal in double heterozygous combination with ast2. S1 ast3 flies are late hatching, those flies which emerge have good viability and fertility, normal wing venation and extremely small eyes. S1/ast4 flies have smaller eyes than S1/+ flies and they also occasionally have gaps at the tips of the longitudinal wing veins. Partially suppresses the phenotype of netunspecified or pxunspecified homozygotes. S1/ast1 tends to completely suppress the phenotype of netunspecified or pxunspecified homozygotes. astrv3 produces a slightly rougher eye than that characteristic of S1/+ in combination with S1.
Bridges, 21st Feb. 1915.