Series Title: Some mathematical models of evolution
Lecture 3: The infinitesimal model and evolutionary rescue
Speaker: Alison Etheridge, OBE FRS, Prof. of Probability and Head of the Department of Statistics, University of Oxford
This lecture is part of the IICD & Probability and Society Initiative Joint Seminar Series, mini-series on Some mathematical models of evolution.
Many of the classical models of natural selection acting on a population suppose that an individual's fitness is determined by its type at some small number of genetic loci. However, in many scenarios selection is acting on a trait that is determined by the accumulation of small effects at a very large number of loci. To model this situation, we introduce the `infinitesimal model' under which within-family trait values are normally distributed (although the values across the whole population could be far from normal), and then use it to investigate `evolutionary rescue' - the process through which maladapted individuals are able to evolve a positive growth rate fast enough to avoid extinction.