Chapter 18, Problem 1U

A genetic map provides

a. the sequence of the DNA in a genome.

b. the relative position of genes on chromosomes.

c. the location of sites of restriction enzyme cleavage in a known sequence of DNA.

d. the banding pattern of a chromosome.

Summary Introduction

Introduction:

A map that is produced at the level of DNA sequence requires the entire sequence of genome. This thing was impossible once technologically. But, fundamentally there are only two types of maps, physical maps and genetic maps.

Answer to Problem 1U

Correct answer:

A genetic map provides the relative position of genes on chromosomes. Therefore, option b. is correct.

Explanation of Solution

Reason for the correct statement:

Genetic maps are also known as linkage maps. This method is used to identify the distance between the genes and the locus of a gene. This map is very important, because it helps in locating the traits on a chromosome.

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

As, “genetic map provides the relative position of genes on chromosomes”, it is the right answer.

Hence, option b. is correct.

Reasons for the incorrect statements:

Option a. is given as “the sequence of the DNA in a genome”.

The sequence of the DNA in a genome can be provided by genome sequencing. So, it is a wrong answer.

Option c. is given as “the location of sites of restriction enzyme cleavage in a known sequence of DNA”.

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

Option d. is given as “the banding pattern of a chromosome”.

Chromosome maps are studied by cytologists to provide the banding patterns of chromosome. So, it is a wrong answer.

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

Conclusion

Genetic maps also called as “linkage maps” are constructed on the basis of frequency obtained from recombination. It provides relative position of a gene on chromosome.