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

Hint: Gene mapping can be defined as a method for determining and identifying the position of a gene, its placement in a chromosome or genome, or the distance between genes.
Alfred Henry Sturtevant was an American geneticist who, in $$1911$$, created the first chromosome genetic map. It was known as the 'linkage map.' The locus is a fixed location on a chromosome that aids in the identification of distinct species or individuals using genetic markers. As previously stated, gene mapping detects this gene locus as well as the distance between genes.

Complete answer:
Option A: Mutation is the source of genetic diversity in a population. Human mutation rates have been estimated to be in the range of $$104-106$$ mutations per gene every generation.
So, option A is not correct
Option B: The percentage of related genes (see linkage) that are exchanged during the first prophase of meiosis during the process of crossing over. The COV is used to map the genes on a chromosome by calculating the percentage of offspring who show recombination.
So, option B is not correct
Option C: A chromosomal map, also known as a linkage map, is a visual representation of the relative distances between the genes in a linkage group. These distances are presented for a single group of chromosomes and are expressed as a percentage of crossing over.
The map unit is an arbitrary unit of measurement for this distance. It's a term that's used to define how far connected genes are apart.
One map unit reflects the linear distance over which one percent of the population crosses over.
$$1$$ map unit equals $$1\mathrm{\%}$$ of crossing over.
As a result, we need to know the recombination frequency, or the percentage of each gene locus that crosses over, in order to determine the map distance of genes on a chromosome.
So, option C is correct.
Option D: Recombination between related genes can be used to map their chromosome distance apart.
So, option D is not correct

So, option C is the correct answer.

Note:
Gene mapping has been used to find genes and their locations on the chromosome that are associated with a disease that is passed down from parent to kid. Genes are thought to play a role in diseases like asthma, diabetes, cancer, psychological disorders, and heart disease. With the use of genomic mapping, scientists can identify these genes.
The Human Genome Project (HGP) has created new and improved techniques for identifying and understanding new gene functions. Genetic mapping is one such approach that has been helpful in identifying genes responsible for rare, gene-inherited illnesses including duchenne muscular dystrophy and cystic fibrosis.