Centimorgans (cM)

Definition

Centimorgans (cM) are units of measure for genetic linkage that describe the distance between chromosome positions. One centimorgan represents a 1% chance that a marker at one genetic locus will be separated from a marker at another locus due to crossing over in a single generation.

5 Must Know Facts For Your Next Test

1. One centimorgan corresponds to approximately one million base pairs in humans, but this can vary between species.
2. Centimorgans are named after the American geneticist Thomas Hunt Morgan.
3. Geneticists use centimorgans to map the relative positions of genes on chromosomes.
4. Crossing over during meiosis is the process responsible for recombination, which centimorgans help quantify.
5. A higher number of centimorgans indicates greater likelihood of recombination occurring between two loci.

Review Questions

• What does one centimorgan represent in terms of genetic linkage?
• Why do geneticists use centimorgans in gene mapping?
• How does the number of centimorgans relate to recombination frequency?

Related terms

Chromosome: Structures within cells that contain DNA and protein, carrying genetic information.

Recombination: The exchange of genetic material between homologous chromosomes during meiosis.

Genetic Locus: A specific location or position on a chromosome where a particular gene or genetic marker is situated.