Muller's ratchetn.

Brit.

/ˌmʊləz ˈratʃɪt/, U.S.

/ˌmʊlərz ˈrætʃət/

Forms:

α. 1900s– Muller's Ratchet.

β. 1900s– Muller ratchet.

Origin: From proper names, combined with an English element. Etymons: proper name Muller , ratchet n.²

Etymology: < the genitive of the name of Hermann Joseph Muller (1890–1967), U.S. geneticist, who proposed the theory in 1964 ( Mutation Res. 1 2) + ratchet n.² In β. forms < Muller + ratchet n.²

Genetics.

A hypothetical mechanism having the effect of invariably increasing the number of harmful mutations in a population of asexually reproducing organisms, since genotypes with the fewest harmful mutations will be among those lost at random in an irreversible manner (likened to a ratchet).The mechanism was proposed to account for the existence of sexual reproduction, which permits the restoration of favourable genotypes by genetic recombination.

ΘΚΠ

the world > life > biology > study > [noun] > genetics > law of

Robertson's law1937

Muller's ratchet1974

1974 Genetics 78 746 Muller's ratchet... The Muller Ratchet mechanism predicts..an increase in the average number of unfavourable mutants present per genome.

1988 Nature 1 Dec. 436/2 Two such [mutation] theories have been proposed. The first of these is a stochastic hypothesis known as Muller's ratchet.

1997 Genetical Res. 70 7 We first show that segregation alone can strongly decelerate Muller's Ratchet in diploids, i.e. that recombination is not the only way to do so.

This is a new entry (OED Third Edition, March 2003; most recently modified version published online March 2022).

单词	mullers ratchet
释义	Muller's ratchetn. Brit. /ˌmʊləz ˈratʃɪt/, U.S. /ˌmʊlərz ˈrætʃət/ Forms: α. 1900s– Muller's Ratchet. β. 1900s– Muller ratchet. Origin: From proper names, combined with an English element. Etymons: proper name Muller , ratchet n.² Etymology: < the genitive of the name of Hermann Joseph Muller (1890–1967), U.S. geneticist, who proposed the theory in 1964 ( Mutation Res. 1 2) + ratchet n.² In β. forms < Muller + ratchet n.² Genetics. A hypothetical mechanism having the effect of invariably increasing the number of harmful mutations in a population of asexually reproducing organisms, since genotypes with the fewest harmful mutations will be among those lost at random in an irreversible manner (likened to a ratchet).The mechanism was proposed to account for the existence of sexual reproduction, which permits the restoration of favourable genotypes by genetic recombination. ΘΚΠ the world > life > biology > study > [noun] > genetics > law of Robertson's law1937 Muller's ratchet1974 1974 Genetics 78 746 Muller's ratchet... The Muller Ratchet mechanism predicts..an increase in the average number of unfavourable mutants present per genome. 1988 Nature 1 Dec. 436/2 Two such [mutation] theories have been proposed. The first of these is a stochastic hypothesis known as Muller's ratchet. 1997 Genetical Res. 70 7 We first show that segregation alone can strongly decelerate Muller's Ratchet in diploids, i.e. that recombination is not the only way to do so. This is a new entry (OED Third Edition, March 2003; most recently modified version published online March 2022). < n.1974
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