Calculating hazard rates of introgression with branching processes

Abstract

Introgression is the permanent incorporation of genes from the genome of one population into that of another through hybridisation and backcrossing. With the advent of genetically modified crops, the potential that transgenes might introgress from cultivated to wild plants has become a point of scientific scrutiny. This thesis presents a methodology by which the risk of introgression can be quantified in terms of empirically determined quantities. A proposed measure of risk is the hazard rate. The hazard rate of introgression is the probability per time unit that introgression occurs given that it has not previously occurred. Particular attention is drawn to demographic stochasticity, genetical mechanisms and both random and deterministic time-inhomogeneities. A sample chapter also outlines the application of the models with empirical data.