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MULLER'S RATCHET AND THE ADVANTAGE OF SEX IN THE RNA VIRUS ϟ 6
Author(s) -
Chao Lin,
Tran Thutrang,
Matthews Crystal
Publication year - 1992
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1992.tb02038.x
Subject(s) - biology , ratchet , ratchet effect , genetics , lineage (genetic) , genetic drift , experimental evolution , mutation rate , evolutionary biology , rna virus , mutation , population , evolution of sexual reproduction , genetic fitness , mutation accumulation , rna , biological evolution , gene , genetic variation , work (physics) , demography , mechanical engineering , sociology , engineering
Population genetic models have shown that if genetic drift is strong and the rate of deleterious mutations is high, Muller's ratchet provides an advantage to sex. A previous study tested for the possibility that Muller's ratchet could work in RNA viruses, which are known to have very high mutation rates. Muller's ratchet was found to operate when lineages of the RNA bacteriophage φ 6 were subjected to intensified genetic drift. The study did not determine, however, whether sex is advantageous to these viruses. We have examined whether sex can reverse the effects of Muller's ratchet by crossing nine φ 6 lineages that were subjected to the ratchet in Chao's study. To determine whether there was a net advantage to sex, we analyzed the effect of crossing three lineages to all other lineages. Crossing increased significantly the fitness of two lineages, but it did not significantly affect the fitness of the third lineage. We argue that the minimal advantage of sex to these nine lineages is small, but positive. These results provide a possible scenario for the evolution of sex in an RNA phage like φ 6.