Centimorgan Centimorgan British Columbia Democratic Coalition Category="Classical genetics"In Genetics, a centimorgan (abbreviated cM) is a unit of Recombinant frequency for measuring Genetic linkage. It is often used to imply distance along a Chromosome. The centimorgan is equal to a 1% chance that a marker at one genetic Locus on a chromosome will be separated from a marker at a second locus due to crossing over in a single generation. A 50 cM distance means that the genes will reassort 50% of the time, which makes them unlinked. Distances greater than or equal to 50 cM are functionally identical with respect to recombination, although farther distances do mean physically greater separation on the chromosome. Note that non-syntenic genes are inherently unlinked, and cM distances have no meaning.

In human beings, one centimorgan is equivalent, on average, to one million base pairs.

The centimorgan was named in honor of geneticist Thomas Hunt Morgan by his student Alfred Henry Sturtevant. Note that the parent unit of the centimorgan, the morgan, is never used.

A map unit (abbreviated m.u.) is synonymous with centimorgan.

See also