The unit of linkage that refers to the distance between two gene loci determined
by the frequency with which recombination occurs between them. Two loci are
said to be one centimorgan apart if recombination is observed between them
in 1% of meioses.
Definition from: GeneReviews
from the University of Washington and the National Center for Biotechnology Information
A centimorgan is a unit used to measure genetic linkage. One centimorgan equals a one percent chance that a marker on a chromosome will become separated from a second marker on the same chromosome due to crossing over in a single generation. It translates to approximately one million base pairs of DNA sequence in the human genome. The centimorgan is named after the American geneticist Thomas Hunt Morgan.