Statistical Mechanics of Convergent Evolution
- Event time: 1:00pm
- Event date: 2nd February 2009
- Speaker: Bhavin Khatri (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
The aim of this work was to try to understand some of the fundamental constraints of evolution from a physics perspective - given a life history of an organism, how reproducible is evolution over an ensemble of identical (aside from stochastic variation) evolutionary experiments. We explore this question of convergent evolution by analysis of the genotype to phenotype map in biology using a simple model of spatial patterning for embryonic development. Building upon the work of Sella and Hirsh (PNAS, (2005), 102, 9541-9546) who identified a direct analogy between the statistical mechanics of the canonical ensemble and the Wright-Fisher evolutionary process, we probe the phenotypic structure that emerges from an underlying genotype. Using Monte Carlo simulations, we show that the emergent evolutionary landscapes share many analogous features to the thermodynamics of physical systems and we highlight some of the unexpected biological consequences in the context of convergent or divergent evolution. In particular, we demonstrate the importance of population size in determining the probability of different evolutionary solutions; the number of ways a phenotype is realised from different genotypes (mutational entropy) and the local roughness of landscapes can make dramatic changes to evolutionary outcomes.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..