Solutions For An Introduction to Genetic Analysis Chapter 17 Problem 61P

a) When we see the cross between California x California and Chile x Chile, the F₁ is testcrossed to give a progeny, which shows that the distance between the two genes is 28 m.u. In the third cross of California x Chile, the distance of 4 m.u. is seen between the two genes.

This result indicates that the gene distance has decreased by 24 m.u. when we calculate the percentage of reduction:

A deletion or a translocation cannot explain this result. Probably, the two lines are inverted for 85.7% of the distance between the two genes.

b) The key chromosomal features of meiosis in the F1 with the genotype of BR/br obtained from a cross of California x Chile would be:

A single crossover would result in 4% crossing between B and R. The products are:

The gametes would be:

• BR

• br

• Br

• bR