Abstract
Natural selection is based on three main principles : the principle of variation, the principle of differential reproductive success, and the principle of heredity. Although natural selection acts on phenotypes, it is mainly the genetics underlying the phenotype that are inherited, so it is the mutations that will be subject to selection. This lecture will look at the different forms that natural selection can take. Each of these forms of selection (purifying, positive, balancing, etc.) leaves molecular signatures detectable on our genomes by various statistical methods, which can also tell us about the timescales at which selection took place.
