Calvin Bridges determined that the rare whiteeyed males prod

Calvin Bridges determined that the rare white-eyed males produced from the mating of true-breeding red-eyed females with white-eyed males resulted from a nondisjunction of X chromosomes in the female parent during meiosis. If such a mating produced 1234 red-eyed progeny and three white-eyed males, what is the observed rate of nondisjunction of the X chromosomes?

Solution

Answer: Choice C

Calculation: The frequency of non-disjunctioning in this case can be calculated as below:

Percentage non-disjunctioniong = Number of non-disjunctioning events * 100 / total events

This gives:

Percentage = 3 * 100 / 1234+7 or 300/1237 = 0.24%