Comprehension Questions

Section 7.1

Question 7.1

What does the term recombination mean? What are two causes of recombination?

Section 7.2

Question 7.2

In a testcross for two genes, what types of gametes are produced with (a) complete linkage, (b) independent assortment, and (c) incomplete linkage?

Question 7.3

What effect does crossing over have on linkage?

Question 7.4

Why is the frequency of recombinant gametes always half the frequency of crossing over?

Question 7.5

What is the difference between genes in coupling configuration and genes in repulsion? How does the arrangement of linked genes (whether they are in coupling or repulsion) affect the results of a genetic cross?

Question 7.6

How would you test to see if two genes are linked?

Question 7.7

What is the difference between a genetic map and a physical map?

Question 7.8

Why do calculated recombination frequencies between pairs of loci that are located far apart underestimate the true genetic distances between loci?

Section 7.3

Question 7.9

Explain how to determine, using the numbers of progeny from a three-point cross, which of three linked loci is the middle locus.

Question 7.10

What does the interference tell us about the effect of one crossover on another?

Section 7.4

Question 7.11

What is a lod score and how is it calculated?

Question 7.12

List some of the methods for physically mapping genes and explain how they are used to position genes on chromosomes.

For more questions that test your comprehension of the key chapter concepts, go to for this chapter.

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