chapter  48
4 Pages

Genetic and Physical Maps

A genetic map is a simplified representation of the genome that consists of lining up all the markers of chromosomes and determining the distances between them. The unit of measurement used (the centimorgan, cM, or unit of genetic distance) is calculated from the frequency of recombination between loci (genetic markers) taken two at a time. In the case of a physical map, the DNA molecule is marked out from molecular markers made up of particular sequences and the distances are expressed in number of base pairs (bp).