SKLCS Seminar

　　Title: the evolutionary benefit of recombination

　　Speaker: Andy Lewis-Pye (London School of Economics, UK)

　　www.aemlewis.co.uk/

　　Time: 28th August 2015, 15:00

　　Venue: Seminar Room (334), Level 3, Building 5, Institute of Software, Chinese Academy of Sciences (CAS), 4 Zhongguancun South Fourth Street, Haidian District, Beijing 100190

　　Abstract:

　　The question as to why most higher organisms reproduce sexually has remained open despite extensive research, and has been called ''the queen of problems in evolutionary biology''. Given the connections to optimisation problems more generally, and especially to issues in genetic algorithms, this is also a question which has recently attracted interest in the computer science community. Theories dating　back to Weismann have suggested that the key must lie in the creation of increased variability in offspring, causing enhanced response to　selection. Rigorously quantifying the effects of assorted mechanisms　which might lead to such increased variability, and establishing that　these beneficial effects outweigh the immediate costs of sexual　reproduction has, however, proved problematic. In recent work with　Montalban, which I shall discuss in this talk, we introduced an　approach which does not focus on particular mechanisms, influencing　factors such as the fixation of beneficial mutants or the ability of　populations to deal with deleterious mutations, but rather tracks the　entire distribution of a population of genotypes as it moves across　vast fitness landscapes. In this setting simulations now show sex　robustly outperforming asex across a broad spectrum of finite or　infinite population models. Concentrating on the additive infinite　populations model, we are able to give a rigorous mathematical proof　establishing that sexual reproduction acts as a more efficient　optimiser of mean fitness, thereby solving the problem for this　model. Some of the key features of this analysis carry through to the　finite populations case.

　　No background knowledge will be required for the talk.