In tomato plants spines s are recessive to no spines S and w

In tomato plants, spines (s) are recessive to no spines (S), and white fruit color (w) is recessive to red fruit color (W). The genes for spines and fruit color are located on the same chromosome; findings from mapping experiments indicate that the recombination frequency between these two genes is 13.2%. A tomato plant having spines and white fruit color is crossed with a plant that is homozygous for no spines and red fruit color. The F1 are crossed with plants that have spines and white fruit color. Which of the following phenotypes and proportions are expected in the progeny of this cross? Check all that apply. Red, no spines = 6.6%; white, spines = 6.6% Red, no spines = 43.4%; white, spines 43.4% White, no spines = 6.6%; red, spines = 6.6% White, no spines = 6.6%; white, spines = 6.6% Red, no spines = 6.6%; red, spines = 6.6% Red, no spines = 43.4%; red, spines = 43.4% White, no spines = 43.4%; white, spines = 43.4% White, no spines = 43.4%; red, spines = 43.4%

Solution

Answer: (b) and (c)

Red, no spines = 43.4%; white, spines = 43.4%

White, no spines = 6.6%; red, spines = 6.6%

Genotype of tomato plant having spines and white fruit color = sw / sw. Genotype of tomato plant homozygous for no spine and red fruit color = SW / SW.

Now perform genetic cross between them, that is: sw / sw x SW / SW

For F1, we get the genotype = SsWw

Now, the cross is : SsWw x ssww

Soving for the cross according to the problem, we get the expected phenotypes as under:

Red, no spines = 43.4%; white, spines = 43.4%

White, no spines = 6.6%; red, spines = 6.6%