Working group: "Computational Biology"

2010, the 09th of February

Dusan Misevic

Title: Evolution of sex: causes, consequences, and predictorsi


The evolution of sexual reproduction has long been a major question in biology. It is a vibrant area of research, rich with theories but poor in experimental results. The crux of the sexual paradox is the dominance of the sexual mode of reproduction, in the natural world, in spite of the apparent costs associated with recombination. In my research I have used computational and theoretical methods to test theories about the evolution of sex, predict when sex will evolve based on those theories and describe the effects of recombination on genomes’ genetic architecture. I have primarily used Avida digital-evolution platform with its evolving computer programs but have also built population genetic and individual based models when appropriate. In particular, I have tested a theory, similar to the famous Red Queen, which proposes that the benefit of sex lies in the quicker adaptation to the changing (abiotic) environment. I have found that sex in Avida did indeed evolve more often when the environment was rapidly changing. However, in spite of these positive results, relatively simple models indicate that predicting sex based on population parameters remains difficult, especially when populations are evolving on complex fitness landscapes and in the presence of strong stochastic effects. On the flip side, while the full range of causes for sex remains elusive, some of its consequences are easier to quantify: genomes of recombining Avida organisms were more modular and exhibited weaker positive epistatic interaction between genes than the genomes of asexually reproducing digital organisms. In the near future, and will investigate the relationship plasmid recombination and cooperative traits, in a different digital system, Aevol, geared more to modeling bacterial genomes. In conclusion, computational approaches I have used have been successful in testing theories and highlighting potentially promising research directions, but much theoretical and experimental work is still needed to fully understand the evolution of sex in nature.