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  • PhyML Maximum Likelihood

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There following parameters are available:

Substitution model parameters - selection of the Markov model of substitution:

Substitution model -  model of substitution.

Equilibrium frequencies -  equilibrium frequencies.

Transition/transversion ratio -  fix or estimate the transition/transversion ratio in the maximum likelihood framework.

Proportion of invariable sites -  the proportion of invariable sites, i.e., the expected frequency of sites that do not evolve, can be fixed or estimated.

Number of substitution rate categories -  number of substitution rate categories.

Gamma shape parameter -  the shape of the gamma distribution determines the range of rate variation across sites.

Branch support parameters - selection of the method that is used to measure branch support:

Use fast likelihood method -  use fast likelihood method.

Perform bootstrap - the support of the data for each internal branch of the phylogeny can be estimated using non-parametric bootstrap.

Tree searching parameters - selection of the tree topology searching algorithm:

Make initial tree automatically -  initial tree automatically.

Type of tree improvement -  type of tree improvement.

Set number of random starting tree -  number of random starting tree.

Optimize topology -  the tree topology is optimised in order to maximise the likelihood.

Optimize branch lengths -  

 

 

Gamma — sets the number of rate categories for the gamma distribution.

You can select the following parameters for the MCMC analisys:

Chain length — sets the number of cycles for the MCMC algorithm. This should be a big number as you want the chain to first reach stationarity, and then remain there for enough time to take lots of samples.

Subsampling frequency — specifies how often the Markov chain is sampled. You can sample the chain every cycle, but this results in very large output files.

Burn-in length — determines the number of samples that will be discarded when convergence diagnostics are calculated.

Heated chains — number of chains will be used in Metropolis coupling. Set 1 to use usual MCMC analysis.

Heated chain temp — the temperature parameter for heating the chains. The higher the temperature, the more likely the heated chains are to move between isolated peaks in the posterior distribution.

Random seed — a seed for the random number generator.

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optimize branch lengths.

Display tree in new window - displays tree in new window.

Display tree with alignment editor - displays tree with alignment editor.

Synchronize alignment with tree - synchronize alignment and tree.

Save tree tofile to save the built tree.

Press the Build button to run the analysis with the parameters selected and build a consensus tree.