DensiTree is a specialized phylogenetic software program designed to visualize large sets or populations of evolutionary trees generated by Bayesian Markov Chain Monte Carlo (MCMC) inference or bootstrapping. Created by Remco Bouckaert, the core concept relies on drawing all trees in a population transparently overlapping one another inside a single image. How DensiTree Creates “Visual Density”
Traditional phylogenetic analysis relies on a single “consensus tree” or “summary tree” to represent a population. This hides variation and conflicts in the data. DensiTree shifts from a quantitative summary to an intuitive qualitative visual summary using transparency:
Dense Colored Areas: Where the trees in the population agree heavily on the evolutionary pathway (topology) and branch length, the overlapping transparent lines merge to form dark, heavily colored sections. These represent high certainty and well-supported groups (clades).
Webs of Lines: In areas where multiple evolutionary trees conflict or show competing topologies, the transparent lines splay apart into a faint, web-like structure. This immediately signals uncertainty to the researcher.
Smears: Vertical node height variations (uncertainty about when a specific evolutionary split occurred) show up as smeared blocks around the average node height. Key Features of DensiTree DensiTree 2: Seeing Trees Through the Forest – bioRxiv
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