centimorgann.
/ˈsɛntᵻˌmɔːɡ(ə)n/, U.S. /ˈsɛntəˌmɔrɡ(ə)n/ Genetics.
In the mapping of chromosomes: a unit used in the measurement of the relative proximity of the loci of two genes on the same chromosome, corresponding to a 1% frequency of recombination between them; one hundredth of a morgan (morgan n.4). Also called map unit.The centimorgan is often used as an indication of distance along a chromosome, since the frequency of recombination between two loci on the same chromosome increases as the distance (number of nucleotides) between them increases. However, the centimorgan is not a measurement of absolute physical distance.
ΚΠ
1919 J. B. S. Haldane in Jrnl. Genetics 8 305 It is suggested that the unit of distance in a chromosome as defined above be termed a ‘morgan’, on the analogy of the ohm, volt, etc. Morgan's unit of distance is therefore a centimorgan.
1961 R. A. Deering et al. Conf. Molecular & Radiation Biol. (National Res. Council) 92 The ar4 locus has been shown to be about 8 centimorgans from its centromere.
1993 Ann. Human Genetics 57 20 (caption) The map distances, in centiMorgans, are shown above the locus order.
2009 J. C. Knight Human Genetic Diversity ii. 58/2 One centimorgan (cM) describes a region in which a cross over event is expected to occur once in every 100 meioses and approximates in physical distance to 1 million bases (1 Mb).
This is a new entry (OED Third Edition, September 2016; most recently modified version published online December 2021).
<
n.1919