Beast bayesian dating
Beast bayesian dating - topdatingskills com
Estimating divergence times using multiple loci (multiple genes or partitions) requires constructing a joint prior on the substitution rates across loci.For example, if we are analysing 10 genes, then we would estimate 10 substitution rates, one for each gene.
As the number of loci in the analysis is increased, the total uncertainty decreases until it reaches a limiting value determined by the fossil calibrations.
Ziheng Yang (University College London), who is working in collaboration with Prof. The named postdoctoral fellow in the grant is Mario dos Reis (University College London).
The project is now finished and this website will not be updated any more.
Critical to molecular dating is the use of fossil information to calibrate the clock.
In this project, we are developing statistical models and computer programs to analyze fossil and molecular data to accurately represent and incorporate the information in the fossil record in molecular dating analysis.
Bayesian estimation of divergence times of extant species using molecular data is an unconventional statistical problem.
Molecular data provide information only about the distances among species on a phylogeny, but not about the geological ages of groups of species nor the molecular evolutionary rate.The discrepancies between estimates of mammalian divergence between molecular and palaeontological studies have been considered unacceptably large.We revised the time-line of mammalian diversification by Bayesian analysis of a large alignment (21 million sites) from 36 mammalian genomes, together with mitochondrial data from 274 mammal species.An important finding is that estimation of deep divergence times (say the root of the phylogeny) can be very sensitive to the parameters of the BDSS prior, even with well serially sampled sequences.You can read the paper by Tanja Stadler and Ziheng Yang published in Systematic Biology in April 2013 here.Because genes accumulate changes over time at a constant rate, the genetic distance between two species, measured by the number of changes accumulated, will be proportional to the time of species divergence.