Chapter 18, Problem 1U

Summary Introduction

Introduction:

In genomics, maps are used to located different gene on a chromosome, subregions of chromosome and so on. Maps of genome are constructed at different levels of resolution using different types of information. Fundamentally, maps can be distinguished into physical maps and genetic maps.

Answer to Problem 1U

Correct answer:

A genetic map is based on the relative position of genes on chromosome. Therefore, option (b) is correct.

Option (b) is given as “relative position of genes on chromosome”.

Explanation of Solution

Justify reason for the correct statement:

Genetic maps are the types of maps that are used to identify the distance between the genes and the locus of a gene. It places relative gene location over the chromosome, based on their recombination frequency.

Hence, option (b) is correct.

Justify reasons for the incorrect statements:

Option (a) is given as “sequence of the DNA”.

The sequence of the DNA can be provided by genome sequencing rather than genetic map. Hence, it is a wrong answer.

Option (c) is given as “location of sites of restriction enzyme cleavage”.

Restriction maps provide the location of site of cleavage by restriction enzyme. Hence, it is a wrong answer.

Option (d) is given as “banding pattern on a chromosome”.

Chromosome maps that are studied by cytologists provide the banding patterns on a chromosome. Hence, it is a wrong answer.

Hence, options (a), (c), and (d) are incorrect.

Conclusion

A genetic map is constructed on the basis of relative location of genes on chromosomes.