Relaxed phylogenetics and dating Free fuck chat scotland no sighn up
We present molecular dating analyses for land plants that incorporate 33 fossil calibrations, permit rates of molecular evolution to be uncorrelated across the tree, and take into account uncertainties in phylogenetic relationships and the fossil record.
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.
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.
It is sometimes called a gene clock or an evolutionary clock.
The independent rates relaxed clock model performed well at all levels of rate variation, although posterior intervals on times were significantly wider than for the strict clock.The strict clock is therefore superior when rate variation is low.The performance of a correlated rates relaxed clock model was similar to the strict clock.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.