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.
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Centimorgan is named after an American geneticist named Thomas Hunt Morgan. He worked on fruit flies, and he defined the capacity of one part of a genome to separate from another in going from one generation to another. And that's important because in every generation chromosomes exchange pieces of information, and that's call recombination. And that's important for introducing genetic diversity into the population. And it was necessary to define a rate at which this happens, and so that's where this term centimorgan comes from. "Centi" means just one-hundredth of, and so if a "morgan" represents the total recombination where all markers of one part of a chromosome will become separated from all others, then a centimorgan is the length of DNA over which that happens only one out of a hundred times, or one percent of the time. So one percent recombination equals a centimorgan. It depends on individual genomes what the distance that a centimorgan represents, and in individual genomes is different from fruit flies and zebrafish and bananas and humans, but given the recombination rate in humans, it represents about a million base pairs in the human genome.
Christopher P. Austin, M.D.
Director, NIH Chemical Genomics Center (NCGC); Senior Advisor for Translational Research, Office of the Director
Dr. Austin's research focuses on development of reagents and technologies to translate genome sequence into functional insights. As director of the NIH Chemical Genomics Center (NCGC), part of a network of screening centers that produce chemical probes for use in biological research and drug development, Dr. Austin is spearheading a chemical genomics program that brings the power of small-molecule chemistry and informatics to the elucidation of gene function. Just as the Human Genome Project accelerated gene identification, this initiative promises to speed discoveries on gene function and lead to the development of new therapies for human disease.