morgan /môr″gən/ [Thomas H. Morgan, American biologist, 1866–1945] , a unit of measure used in mapping the relative distances between genes on a chromosome. The measurement uses the total crossover value as the basic unit so that 1 morgan equals 100% crossing over or 1 centimorgan equals 1% recombination. One centimorgan is also equal to one map unit. See also map unit.
