Bayesian molecular clock dating of phylogenies: Fossils, genomes and uncertainty

Molecular sequences provide information about the relative distances of species in a phylogeny, but not on the geological times of divergence or the molecular evolutionary rates.

This statistical non-identifiably of times and rates is problematic, making posterior estimates of divergence times highly sensitive to uncertainties present in the rate prior and in the fossil-based probability densities used to calibrate the phylogeny.

Here I discuss the theoretical basis of uncertainty on divergence time estimates, and describe the novel research strategies being used to tackle the issue. Results from our analysis of divergence times in various groups (such as mammals, or the divergence of early animals) are discussed.