Solutions For An Introduction to Genetic Analysis Chapter 4 Problem 52P

a) The data shows that the 3 genes are linked. The parental chromosomes are the most common progeny with the genotypes k c + and + + e. The category with the lowest number represents the double crossover events. After comparing these two classes, the middle gene is determined to be e.

Number of genotypes between k and e are as follows:

• + + - 4+58

• + e – 44+899

• k + - 876+49

• k e - 3+67

The lowest numbers indicate that they are the recombinant classes. Hence, the number of recombinants would be:

Number of genotypes between e and c are as follows:

• + + - 49+4

• + e – 876+58

• k + - 899+67

• k e – 44+3

The lowest numbers indicate that they are the recombinant classes. Hence, the number of recombinants would be:

The map distance between k and e can be calculated in this way:

The map distance between e and c can be calculated in this way:

b) The chromosomes of the parents and the F₁ are represented as follows:

c) The expected frequency of double crossovers would be:

The actual frequency of double crossovers seen in the progeny is:

The formula for interference is:

The interference is negative since interference values are generally between 0 and 1. The difference between the expected and observed values is not very significant.