Through mathematical models, we study how such Red Queen dynamics arise and how they are influenced by various factors. For example, we have recently shown that if environmental conditions alter the way that hosts and parasites interact genetically, then changing environments can both annihilate Red Queen dynamics that would otherwise occur, or generate Red Queen dynamics that would not occur in a constant environment (Mostowy & Engelstädter 2011). Other factors that we are interested in include properties of the infection genetics (Engelstädter & Bonhoeffer 2009), protective endosymbionts (Kwiatkoswki et al. 2012) and non-genetic inheritance (Mostowy et al. 2012).