Question

A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W, shown below.

1) Assume A and B are dominant alleles. If this individual were crossed to an individual of genotype Aa Bb, what is the probability of a female offspring with the two dominant traits given by alleles A and B?
2) From what type of individual is this cell?

Answer 1

The probability of a female offspring with two dominant traits is 25%.

Step-by-step explanation:

In organisms with the ZZ-ZW sex determination system, individuals with the genotype ZZ are males, and those with the genotype ZW are females. The question asks about the probability of a female offspring with two dominant traits, represented by alleles A and B, when crossed with an individual of genotype Aa Bb.

To determine the probability, we need to analyze the possible genotypes of the offspring. The genotype of the individual being crossed is Aa Bb, which means it can produce eggs with the alleles Aa or Ab and sperm with the alleles Aa or Bb. When these gametes combine with the ZW chromosomes, there are four possible combinations: ZW-AaAa, ZW-AaAb, ZW-BbAa, and ZW-BbAb.

Out of these four possibilities, only the ZW-AaAb combination results in a female offspring with two dominant traits (alleles A and B). Therefore, the probability of a female offspring with the two dominant traits is 1 out of 4, or 25%.