Suppose you are carrying out a series of crosses with an ins

Suppose you are carrying out a series of crosses with an insect where the mechanism of sex determination is unknown. You discover a mutant male with black wing scales and decide to cross it with a wild type female that has gray wing scales. Half of the F_1 progeny have black wing scales but all of these F_1 progeny with black wing scales are males. Based on these results, a valid hypothesis would be Females are XX. males are XY and black wing scales are caused by n recessive allele on the X chromosome Females are XX. males are XY and black wing scales are caused by a dominant allele on the X chromosome. Females are ZW. males are ZZ and black wing scales are caused by a recessive allele on the Z chromosome. Females are ZW, males are 11 and black wing scales are caused by a dominant allele on the Z chromosome.

Solution

Females are ZW, males are ZZ and black wing scales are caused by a dominant allele on the Z chromosome.