Below is a partial pedigree of hemophilia in the British Royal Family descended from Queen Victoria, who is believed to be the original 'carrier' in this pedigree.

Analyze the pedigree and indicate which females are also certain to be carriers. What is the probability that Princess Irene is a carrier?

Students taking a genetics exam were expected to answer the following question by converting data to a 'meaningful ratio' and then solving the problem. The instructor assumed that the final ratio would reflect two gene pairs, and most correct answers did. Here is the exam question: 'Flowers may be white, orange, or brown. When plants with white flowers are crossed with plants with brown flowers, all the F₁ flowers are white. For F₂ flowers, the following data were obtained:

48 white

12 orange

4 brown

Convert the F₂ data to a meaningful ratio that allows you to explain the inheritance of color. Determine the number of genes involved and the genotypes that yield each phenotype.'

A number of students failed to reduce the ratio for two gene pairs as described above and solved the problem using three gene pairs. When examined carefully, their solution was deemed a valid response by the instructor. Solve the problem using three gene pairs

In four o'clock plants, many flower colors are observed. In a cross involving two true-breeding strains, one crimson and the other white, all of the F₁ generation were rose color. In the F₂, four new phenotypes appeared along with the P₁ and F₁ parental colors. The following ratio was obtained:

1/16 crimson

4/16 rose

2/16 orange

2/16 pale yellow

1/16 yellow

4/16 white

2/16 magenta

Propose an explanation for the inheritance of these flower colors.

Students taking a genetics exam were expected to answer the following question by converting data to a 'meaningful ratio' and then solving the problem. The instructor assumed that the final ratio would reflect two gene pairs, and most correct answers did. Here is the exam question: 'Flowers may be white, orange, or brown. When plants with white flowers are crossed with plants with brown flowers, all the F₁ flowers are white. For F₂ flowers, the following data were obtained:

48 white

12 orange

4 brown

Convert the F₂ data to a meaningful ratio that allows you to explain the inheritance of color. Determine the number of genes involved and the genotypes that yield each phenotype.'

We now have a dilemma. The data are consistent with two alternative mechanisms of inheritance. Propose an experiment that executes crosses involving the original parents that would distinguish between the two solutions proposed by the students. Explain how this experiment would resolve the dilemma.