| 1A4 - 20 . 20F - 20A1 |
More viable than R(1)1; X/0 male survives. Ordinarily, ring elimination less than 1% (Battacharya, 1950, Proc. R. Soc. Edinburgh, B 64: 199-215; Braver and Blount, 1950, Genetics 35: 98), but nearly 20% of the first progeny of 11-day-old females crossed to ring-bearing males are gynandromorphs (Hannah, 1955, Z. Indukt. Abstamm. Vererbungsl. 86: 600-21). Number of male nuclei in eggs of gynandromorphs varies greatly, suggesting that loss of the ring X may occur more than once and that it may take place as late as the ninth cleavage (Zalokar, 1980, Cell 19: 133-41). Crossing over reduced in ring/rod heterozygote; only double crossovers recovered. Exceptional males result from 4-strand double exchange in R(1)2/+ female.
Beadle, 34b (ring nature discovered by Boche).