Spontaneous mutation accumulation in multiple strains of the green alga, Chlamydomonas reinhardtii

Andrew D Morgan, Rob W Ness, Peter D Keightley, N Colegrave

Research output: Contribution to journalArticlepeer-review

Abstract

Estimates of mutational parameters, such as the average fitness effect of a new mutation and the rate at which new genetic variation for fitness is created by mutation, are important for the understanding of many biological processes. However, the causes of interspecific variation in mutational parameters and the extent to which they vary within species remain largely unknown. We maintained multiple strains of the unicellular eukaryote Chlamydomonas reinhardtii, for approximately 1000 generations under relaxed selection by transferring a single cell every ∼10 generations. Mean fitness of the lines tended to decline with generations of mutation accumulation whilst mutational variance increased. We did not find any evidence for differences amongst strains in any of the mutational parameters estimated. The overall change in mean fitness per cell division and rate of input of mutational variance per cell division were more similar to values observed in multicellular organisms than to those in other single celled microbes. However, after taking into account differences in genome size amongst species, estimates from multicellular organisms and microbes, including our new estimates from C. reinhardtii, become substantially more similar. Thus, we suggest that variation in genome size is an important determinant of interspecific variation in mutational parameters. This article is protected by copyright. All rights reserved.

Original languageEnglish
Pages (from-to)2589-2602
Number of pages14
JournalEvolution
Volume68
Issue number9
DOIs
Publication statusPublished - 14 May 2014

Keywords

  • Genomic deleterious mutation rate
  • Mutation accumulation
  • Mutational effect
  • Spontaneous mutation

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