Co-evolution of host and endosymbiont genomes during Eukaryogenesis: the role of sexual reproduction
Summary
Sexual reproduction is a trait shared in all eukaryotes, and was present in the last eukaryotic common ancestor. Current eukaryotes mostly inherit mitochondria from one parent, but the mechanisms that ensure this vary hugely in different species, and the ancestral trait is unknown. It is unknown when sex appeared in relation to the acquirement of mitochondria and its role in the evolution of endosymbiosis. In this project, a multilevel, individual based model of endosymbiosis (von der Dunk et al., 2023) is used to study the role sex in the co-evolution of host and symbiont genomes. Evolutionary simulations were performed on populations of cells that live on a 2D grid, each cell consisting of one host and one or more symbionts, the latter inherited by one parent (asexual reproduction) or two parents (sexual reproduction). Our results indicate that sex poses threats, due to the emergence of selfish symbionts that can drive populations to extinction. However, resolution of this conflict is possible, and can drive the evolution of signalling, allowing the host to control the symbiont’s cell cycle. In fact, in many cases the populations that survive sexual reproduction outperform the asexual populations that evolve under the same conditions.