Two genes determine summer squash color. The dominant W allele inhibits pigment production, resulting in white squash, while the recessive w allele allows color pigments to be produced. In ww homozygotes, the second gene determines color: the G allele produces green squash, while the g allele produces yellow squash (G is dominant over g).

A white squash plant was crossed with a yellow squash plant, producing 50% white and 50% green squash in the F₁ generation.

What are both parents' genotypes?

If an individual is heterozygous for two linked genes, how many different combinations of alleles for these genes can be present in its gametes if crossing over occurs during meiosis? Additionally, how many combinations can be present if crossing over does not occur? Please explain your answer.

Explain the main differences between dominance, incomplete dominance, and codominance.

The figure illustrates the inheritance of cystic fibrosis across three generations of a family.

a) Is cystic fibrosis a dominant or recessive trait?

b) What are the genotypes of the following individuals?

• II-2

• II-3

• II-4

• III-5

c) Individual III-5 would like to start a family. What is the probability that their child will inherit the cystic fibrosis allele?