Disjunction of mini-X chromosomes from BSY

Female progenybMale progenyb
Mini-Xayy+y BSy+ BSy wy+ wy w BSy+ w BSNcNDJd
  • a Males of the genotype Df(1)X-1, y/BSY/Dp, y+ were crossed singly to y w females. Df(1)X-1 is an X chromosome deficient for most of the proximal heterochromatin.

  • b y+ progeny carry the Dp. BS progeny carry BSY.

  • c N, total progeny.

  • d NDJ = Dp-BSY NDJ = ((y + y+ BS females) + (y w + y+ w BS males) − 0.5(1 − T)N)/NT. T = 0.95. In this genotype, X, Y, XY, and O nuclei are produced at equal frequencies during meiosis but a strong progeny ratio distortion occurs via spermatid and/or sperm elimination (McKee and Lindsley 1987). The probability of elimination is proportional to chromatin content so Dp recoveries are reduced in this cross relative to the crosses in other tables. Consequently, statistical tests for differences between observed NDJ frequencies and NDJ = 0.5 are not valid and were not done. However, comparisons between genotypes differing only by Dp identity using contingency tests are valid. Asterisks indicate the significance level of the contingency tests for the difference from the Dp1187 control. **P < 0.01.