Becker's World of the Cell 9th Edition by Lewis Kleinsmith, Jeff Hardin, Gregory Paul Bertoni

Exercise 9

Genetic Mapping. The following table provides data concerning the frequency with which four genes ( w , x, y, and z)located on the same chromosome recombine with each other.
(a)Construct a genetic map indicating the order in which these four genes occur and the number of map units that separate the genes from each other.
(b)In constructing this map, you may have noticed that the map distances are not exactly additive. Can you provide an explanation for this apparent discrepancy