Essential Genetics 6th Edition by Daniel Hartl

Exercise 5

Fruit flies with the chromosome constitution XXY are fertile females. Random segregation of the sex chromosomes results in eggs of the following chromosomal types and frequencies: XX (1/6), XY (1/3), X (1/3), Y (1/6). If an XXY female is crossed with a normal XY male, what is the expected fraction of fertilized eggs that will survive? (Note: In this cross, fertilized eggs with sex chromosome constitutions XXX and YY die; all others survive.)