The effects of sex on extinction dynamics of Chlamydomonas reinhardtii depend on the rate of environmental change.

The continued existence of sex, despite many the costs it entails, still lacks an adequate explanation, as previous studies demonstrated that the effects of sex are environment-dependent: sex enhances the rate of adaptation in changing environments, but the benefits level off in benign conditions. To the best of our knowledge, the potential impact of different patterns of environmental change on the magnitude of these benefits received less attention in theoretical studies. In this paper, we begin to explore this issue by examining the effect of the rate of environmental deterioration (negatively correlated with population survival rate), on the benefits of sex.

The effect of heterospecific and conspecific competition on inter-individual differences in tungara frog tadpole () behavior.

Repeated social interactions with conspecifics and/or heterospecifics during early development may drive the differentiation of behavior among individuals. Competition is a major form of social interaction and its impacts can depend on whether interactions occur between conspecifics or heterospecifics and the directionality of a response could be specific to the ecological context that they are measured in. To test this, we reared tungara frog tadpoles () either in isolation, with a conspecific tadpole or with an aggressive heterospecific tadpole, the whistling frog tadpole ().

The distribution of fitness effects of spontaneous mutations in Chlamydomonas reinhardtii inferred using frequency changes under experimental evolution.

The distribution of fitness effects (DFE) for new mutations is fundamental for many aspects of population and quantitative genetics. In this study, we have inferred the DFE in the single-celled alga Chlamydomonas reinhardtii by estimating changes in the frequencies of 254 spontaneous mutations under experimental evolution and equating the frequency changes of linked mutations with their selection coefficients. We generated seven populations of recombinant haplotypes by crossing seven independently derived mutation accumulation lines carrying an average of 36 mutations in the haploid state to a mutation-free strain of the same genotype.

De Novo Mutation Rate Variation and Its Determinants in Chlamydomonas.

De novo mutations are central for evolution, since they provide the raw material for natural selection by regenerating genetic variation. However, studying de novo mutations is challenging and is generally restricted to model species, so we have a limited understanding of the evolution of the mutation rate and spectrum between closely related species. Here, we present a mutation accumulation (MA) experiment to study de novo mutation in the unicellular green alga Chlamydomonas incerta and perform comparative analyses with its closest known relative, Chlamydomonas reinhardtii.