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Unpredictable repeatability in molecular evolution

delete2022-09-19
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OA
AI
S
Suman G. Das *
J
Joachim Krug
DOI:10.1073/pnas.2209373119delete
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Abstract

Abstract

En 中文
The extent of parallel evolution at the genotypic level is quantitatively linked to the distribution of beneficial fitness effects (DBFE) of mutations. The standard view, based on light-tailed distributions (i.e., distributions with finite moments), is that the probability of parallel evolution in duplicate populations is inversely proportional to the number of available mutations and, moreover, that the DBFE is sufficient to determine the probability when the number of available mutations is large. Here, we show that when the DBFE is heavy-tailed, as found in several recent experiments, these expectations are defied. The probability of parallel evolution decays anomalously slowly in the number of mutations or even becomes independent of it, implying higher repeatability of evolution. At the same time, the probability of parallel evolution is non-self-averaging-that is, it does not converge to its mean value, even when a large number of mutations are involved. This behavior arises because the evolutionary process is dominated by only a few mutations of high weight. Consequently, the probability varies widely across systems with the same DBFE. Contrary to the standard view, the DBFE is no longer sufficient to determine the extent of parallel evolution, making it much less predictable. We illustrate these ideas theoretically and through analysis of empirical data on antibiotic-resistance evolution.
Keywords:
parallel evolution
distribution of fitness effects
predictability of evolution
antibiotic resistance
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Journal

P
Proceedings of the National Academy of Sciences of the United States of America
IF:
9.1
Papers:
10.8W
Citations:
73.5W

Organization

U
University of Cologne
Scholars:
3.0W
Papers: 2.1W
Citations: 2.4W