LINKAGE MAP
This map gives a specific location to a gene by assigning distances
between genes. However, this location may not start at the beginning of
a chromosome or run all the way through it. Instead, it is a portion of the chromosome that has located genes and distances between genes, much like that of a road
map which indicates towns along an interstate. This map is used when
wanting to obtain an overall view of a large portion of DNA on a
chromosome and to select for genes that influence certain traits. The
lesser distance (in units called centimorgans or cM), the closer the
genes are to each other.
Linkage Map Example