Assume that in watermelon plants the genes for flower color (Y = yellow;y = orange flowers) and fruit shape (R = round;r = oval) are on the same chromosome.You cross two true-breeding plants,one with yellow flowers and round fruit and the other with orange flowers and oval fruit.You take one of the F₁ individuals and cross it with a plant that is homozygous recessive for both traits.You get the following in the F₂: 300 yellow flowers,round fruit;300 orange flowers,oval fruit;100 yellow flowers,oval fruit,100 orange flowers,round fruit.
The recombination frequency observed in experimental crosses can be used to indicate distances between genes on a chromosome.More specifically,the map distance between two genes is equal to the frequency of recombinant offspring.What is the map distance between the genes for flower color and fruit shape?

Question

Quizplus · Accepted Answer

The map distance between the genes for flower color and fruit shape is calculated based on the frequency of recombinant offspring. In this case, the recombinant offspring are those with yellow flowers and oval fruit (100) and those with orange flowers and round fruit (100), totaling 200 recombinant offspring out of 800 total offspring (300 + 300 + 100 + 100). The recombination frequency is (200/800) * 100 = 25%, indicating a map distance of 25.0 map units between the two genes.

Assume That in Watermelon Plants the Genes for Flower Color