Question

In order to calculate map distance of genes on a chromosome, what must we know?

• A. Number of mutant genes
• B. Cross over percentage
• C. Recombination frequency of each gene locus
• D. Non-cross over percentage

Answer 1

Answer: (C)

Recombination frequency of each gene locus

A linkage map or chromosomal is a graphic representation of the relative distances between the genes in a linkage group. These distances are expressed in terms of percentage of crossing over and given for a single group of chromosomes.

An arbitrary unit of measurement of this distance is map unit. It is used to describe the distances between the linked genes.

One map unit represents the linear distance within which one percent crossing over takes place.

1 map unit = 1% of crossing over

Hence, in order to calculate map distance of genes on a chromosome, we must know recombination frequency i.e. crossing over percentage of each gene locus.

So, the correct answer is 'Recombination frequency of each gene locus'.