dorsal/arxiv
View SchemaBeneficial mutation-selection balance and the effect of linkage on positive selection
| Authors | Michael M. Desai, Daniel S. Fisher |
|---|---|
| Categories | |
| ArXiv ID | q-bio/0612016 |
| URL | https://arxiv.org/abs/q-bio/0612016 |
Abstract
When beneficial mutations are rare, they accumulate by a series of selective sweeps. But when they are common, many beneficial mutations will occur before any can fix, so there will be many different mutant lineages in the population concurrently. In an asexual population, these different mutant lineages interfere and not all can fix simultaneously. In addition, further beneficial mutations can accumulate in mutant lineages while these are still a minority of the population. In this paper, we analyze the dynamics of such multiple mutations and the interplay between multiple mutations and interference between clones. These result in substantial variation in fitness accumulating within a single asexual population. The amount of variation is determined by a balance between selection, which destroys variation, and beneficial mutations, which create more. The behavior depends in a subtle way on the population parameters: the population size, the beneficial mutation rate, and the distribution of the fitness increments of the potential beneficial mutations. The mutation-selection balance leads to a continually evolving population with a steady-state fitness variation. This variation increases logarithmically with both population size and mutation rate and sets the rate at which the population accumulates beneficial mutations, which thus also grows only logarithmically with population size and mutation rate. These results imply that mutator phenotypes are less effective in larger asexual populations. They also have consequences for the advantages (or disadvantages) of sex via the Fisher-Muller effect; these are discussed briefly.
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"abstract": "When beneficial mutations are rare, they accumulate by a series of selective\nsweeps. But when they are common, many beneficial mutations will occur before\nany can fix, so there will be many different mutant lineages in the population\nconcurrently. In an asexual population, these different mutant lineages\ninterfere and not all can fix simultaneously. In addition, further beneficial\nmutations can accumulate in mutant lineages while these are still a minority of\nthe population. In this paper, we analyze the dynamics of such multiple\nmutations and the interplay between multiple mutations and interference between\nclones. These result in substantial variation in fitness accumulating within a\nsingle asexual population. The amount of variation is determined by a balance\nbetween selection, which destroys variation, and beneficial mutations, which\ncreate more. The behavior depends in a subtle way on the population parameters:\nthe population size, the beneficial mutation rate, and the distribution of the\nfitness increments of the potential beneficial mutations. The\nmutation-selection balance leads to a continually evolving population with a\nsteady-state fitness variation. This variation increases logarithmically with\nboth population size and mutation rate and sets the rate at which the\npopulation accumulates beneficial mutations, which thus also grows only\nlogarithmically with population size and mutation rate. These results imply\nthat mutator phenotypes are less effective in larger asexual populations. They\nalso have consequences for the advantages (or disadvantages) of sex via the\nFisher-Muller effect; these are discussed briefly.",
"arxiv_id": "q-bio/0612016",
"authors": [
"Michael M. Desai",
"Daniel S. Fisher"
],
"categories": [
"q-bio.PE",
"q-bio.GN"
],
"title": "Beneficial mutation-selection balance and the effect of linkage on positive selection",
"url": "https://arxiv.org/abs/q-bio/0612016"
},
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