Essentials of Genetics 9th Edition by Michael Palladino William Klug, Michael Cummings, Charlotte Spencer

Exercise 1

In this chapter, we focused on linkage, chromosomal mapping, and many associated phenomena. In the process, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions?
(a) How was it established experimentally that the frequency of recombination (crossing over) between two genes is related to the distance between them along the chromosome?
(b) How do we know that specific genes are linked on a single chromosome, in contrast to being located on separate chromosomes?
(c) How do we know that crossing over results from a physical exchange between chromatids?
(d) How do we know that sister chromatids undergo recombination during mitosis?