Species delimitation from genetic data – a quantitative assessment of a spatiotemporal approach

Despite its fundamental status in biology, the species category definition remains controversial and quantitative methods to test species status are in their infancy. One aspect of the controversy that to a large extent has been neglected is the difference between assigning individual organisms into species, versus assigning alleles. In this project, I will concentrate on species as being composed of genetic material with a common historical ancestry. The recently developed multi-species coalescent (MSC) model defines species as the branches of the phylogenetic tree. This means that in the MSC model, species have a unique ontological status different from clades (groups of species with a common ancestry). However, these “species” better correspond to the concept of population, as they rely on assumptions that are grossly violated in what biologist’s usually consider as species. In this project, I will explore empirical multi-locus DNA sequence data sets previously analyzed in a MSC context, but here I will develop an approach that take hybridization and spatial scales into account. The fit of the data sets to the models will be quantified and be used to simulate new data that can be used for evaluation of accuracy and computational feasibility.