先见教程：http://abacus.gene.ucl.ac.uk/software/MCMCtree.Tutorials.pdf
The tree file looks like this
71
((((human, (chimpanzee, bonobo)) '>.06<.08', gorilla), (orangutan, sumatran)) '>.12<.16', gibbon);
//end of file
((((human, (chimpanzee, bonobo)) 'B(.06, .08)', gorilla), (orangutan, sumatran)) 'B(.12, .16)', gibbon);
The first line has the number of species (7) and the number of trees (1). Then the tree in Newick format is given. The tree must not have branch lengths. The tree has two fossil calibrations, one for the most recent common ancestor of human-chimp: ’> .06 < .08’ and another for the most recent common ancestor of the greater apes: ’> .12 < .16’. The time unit is 100 Million years (Myr). So the first calibration restricts the common ancestor of human-chimp to be between 6-8 Myr ago.
由原文程序设定可知，分子钟的时间单位是100 Million years (Myr)，所以在运行MCMCTree分析时输入的时间校正单位也应该是100百万年
<in.tree> newick format rooted tree with calibration time
