title: Fitness Effects of Spontaneous Mutations in Picoeukaryotic Marine Green Algae.
abstract: Estimates of the fitness effects of spontaneous mutations are important for understanding the adaptive potential of species. Here, we present the results of mutation accumulation experiments over 265-512 sequential generations in four species of marine unicellular green algae, Ostreococcus tauri RCC4221, Ostreococcus mediterraneus RCC2590, Micromonas pusilla RCC299, and Bathycoccus prasinos RCC1105. Cell division rates, taken as a proxy for fitness, systematically decline over the course of the experiment in O. tauri, but not in the three other species where the MA experiments were carried out over a smaller number of generations. However, evidence of mutation accumulation in 24 MA lines arises when they are exposed to stressful conditions, such as changes in osmolarity or exposure to herbicides. The selection coefficients, estimated from the number of cell divisions/day, varies significantly between the different environmental conditions tested in MA lines, providing evidence for advantageous and deleterious effects of spontaneous mutations. This suggests a common environmental dependence of the fitness effects of mutations and allows the minimum mutation/genome/generation rates to be inferred at 0.0037 in these species.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls/Mer, France krasovec@obs-banyuls.fr gwenael.piganeau@obs-banyuls.fr.
authors.forename: Marc
authors.initials: M
authors.lastname: Krasovec
authors.affiliation: School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
authors.forename: Adam
authors.initials: A
authors.lastname: Eyre-Walker
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls/Mer, France.
authors.forename: Nigel
authors.initials: N
authors.lastname: Grimsley
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Observatoire Océanologique de Banyuls (OOB) , F-66650 Banyuls/Mer, France and.
authors.forename: Christophe
authors.initials: C
authors.lastname: Salmeron
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Observatoire Océanologique de Banyuls (OOB) , F-66650 Banyuls/Mer, France and.
authors.forename: David
authors.initials: D
authors.lastname: Pecqueur
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls/Mer, France krasovec@obs-banyuls.fr gwenael.piganeau@obs-banyuls.fr.
authors.forename: Gwenael
authors.initials: G
authors.lastname: Piganeau
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, F-66650 Banyuls/Mer, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Sanchez-Ferandin
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D059001:Aquatic Organisms / Q000187:drug effects / Q000235:genetics*; D002455:Cell Division / Q000187:drug effects; D000460:Chlorophyta / Q000187:drug effects / Q000235:genetics*; D056084:Genetic Fitness; D006540:Herbicides / Q000633:toxicity; D059645:Mutation Rate; D009994:Osmolar Concentration; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D013312:Stress, Physiological
chemical_list: D006540:Herbicides; D012965:Sodium Chloride
keywords: fitness effects; marine pico-phytoplankton; mutation accumulation; single cell cultures; spontaneous mutation