The evolution of cooperative behavior, is among the most intriguing questions in evolutionary biology, and had been studied since Darwin’s time. In our lab we investigate mechanisms that allow the evolution of cooperation and study their implications.
Most evolutionary models implicitly assume that genetic variation has a uniform rate at all times. In contrast, we explore an alternative hypothesis: that the generation of variation is plastic, its rate depending on the state of the organism, so that stressed individuals have a higher tendency for variation. From the perspective of a gene regulating the generation of variation (e.g., the rate of mutation), stress responses may indicate that it is maladapted to the current environment. By increasing the rate of variation when stressed the allele can increase its own chances of having a different genetic background in the next generation. Vice versa, by decreasing the rate of variation when the individual is feeling perfectly well it can increase its chances of staying linked to a good genetic background.
Most organisms are subject to evolution at more than one level: conflicts of interest can occur between branches of a tree, between different lineages within the germ line, and within the cells in the germ line themselves. A single eukaryotic cell is a community, including organelles, such as mitochondria and chloroplast, transposable elements, and the 'host' DNA. We study the interactions between these different evolutionary levels, and their implications to the higher levels: the entire organism and the population.
The evolution of sex is one of the most puzzling questions in evolutionary biology, because of the two-fold ‘cost of males’. To account for the high abundance of sex in the world, sexual reproduction should have at least a two-fold advantage over asexuality. Despite many attempts, it remains a major challenge to find an explanation that will account for the prevalence of sex under the varied conditions found in nature. An even harder question is why so many organisms reproduce sexually so often: according to almost all the current theories, rare sexual encounters supplementing common asexual reproduction would carry most of the benefits of sex and very few of its disadvantages. We are studying these questions in the context of three different factors: sexual selection, epigenetic regulation and the co-evolution of mutation and sex.
Plants and pollinators share a fascinating and complicated mutually beneficial relationship. Pollinators contribute to the reproductive efforts of plants, by collecting pollen from one plant and depositing it in another same-species plant. For this effort, they are reimbursed with food, shelter, heat or possible encounters with mates. Pollination is crucial for the survival of many plant species, and has a major effect on plant diversity. We employ theoretical models as well as experiments to explore the various interactions of plants and pollinators.
An open question in evolutionary biology is how a species can evolve from one co-adapted gene complex to a better one, crossing an adaptive 'valley' of less fit genotypes. We study how such adaptive peak-shifts are affected by genetic mixing and by heterogeneity of the environment.