Question

Genetic map is one that
A. Establishes sites of the gene on a chromosome
B. Established the various stages in gene evolution
C. Shows the stages during cell division
D. Shows distribution of various species in a region

Answer 1

A genome map reveals the distribution of a set of loci present within the genome. Genetic map is a method for determination of location of genes and relative distances between genes on a chromosome. On the basis of method of construction and metric for measurement of distance between genes, there are three types of maps available. They are physical, chromosomal and linkage maps.

Complete answer
A chromosomal map displays the relative positions of the genes along the length of a chromosome. The genes are placed by cytogenetic analysis or linkage values.
Linkage maps are drawn on the basis of recombination frequency, which is directly proportional to the distance between the genes. The values are utilized to locate the genes on a chromosome. This is developed on the basis of Morgan’s hypothesis that the frequency of crossing over or recombination between two linked genes is directly proportional to the physical distance between the two genes. A centimorgan or map unit is equivalent to recombination between two genes.
The physical map is based on the direct DNA analysis and constructed by the direct measurement of physical distances between and within loci. The units used are basepairs, kilobase pairs and megabase pairs.
Option A Establishes sites of the gene on a chromosome: Bases on the above discussion, the genetic map is helpful in establishing the sites of the gene on a chromosome.
Option A is correct
Option B Establishes the various stages in gene evolution: Gene evolution is irrelevant to the genetic map.
Hence, Option B is not correct
Option C Shows the stages during cell division: Stages of cell division are not represented by maps.
So, Option C is not correct
Option D Shows distribution of various species in a region: Species and biodiversity are not related to genetic map.
Option D is not correct

Therefore, Option A is the correct answer

Note:
The essence of genome mapping is placing a collection of molecular markers onto their respective positions on the genome. A linkage map is a graphic representation of relative positions or order and relative distance of genes in a chromosome in the form of a line like a road map showing various places and their relative distances without providing exact mileage.