The benchmarks for determining the mutation rate are often fossil or archaeological dates.
The molecular clock was first tested in 1962 on the haemoglobin protein variants of various animals, and is commonly used in molecular evolution to estimate times of speciation or radiation.
We attached a prior probability to each fossil-based minimum age, and explored the effects of relying on the first appearance of tricolpate pollen grains as a lower bound for the age of eudicots.
Thus, including both the global molecular clock and the unconstrained model results, there are a total of 2 We propose an efficient method to sample this model space while simultaneously estimating the phylogeny.
The new method conveniently allows a direct test of the strict molecular clock, in which one rate rules them all, against a large array of alternative local molecular clock models.
The new method approaches the problem of rate variation among lineages by proposing a series of local molecular clocks, each extending over a subregion of the full phylogeny.
Each branch in a phylogeny (subtending a clade) is a possible location for a change of rate from one local clock to a new one.