Q.What is gene mapping ? Write its uses.

Gene mapping determines the order and distance of genes on a chromosome using recombination frequency, and underlies disease-gene identification, breeding and genome sequencing.

Working

Gene mapping (genetic/linkage mapping) is the determination of the relative positions of genes along a chromosome and the genetic distance separating them. It is based on the principle, established by A. H. Sturtevant, that genes located closer together on the same chromosome are less likely to be separated by crossing over during meiosis than genes located farther apart; the observed recombination frequency between two linked genes is therefore used as a proportional measure of the distance between them, expressed in map units (centimorgans), where 1% recombination frequency corresponds to 1 map unit. By working out the recombination frequencies between several linked genes, their linear order and relative spacing along a chromosome can be worked out and represented as a genetic (linkage) map.

Uses of gene mapping:

1. It reveals the actual linear arrangement/sequence of genes along a chromosome.
2. It helps in identifying and locating genes responsible for inherited diseases/disorders, aiding genetic diagnosis and counselling. …