WANI Dictionary

Root (phylogenetics)

In phylogenetics, the root is the most recent common ancestor of all taxa in the phylogenetic tree.

The root indicates the oldest point of the tree, adding concept of the direction of evolution to the tree. Unrooted phylogenetic tree simply represents the genetic distances between taxa without the concept.

Definitions in the literature

• The root is the most recent common ancestor of all of the taxa in the tree. It is therefore the oldest part of the tree and tells us the direction of evolution, with the flow of genetic information moving from the root, towards the tips with each successive generation [1].
• rooted tree: Phylogenetic tree in which one node represents a common ancestor to all other organisms (nodes) on the tree [2].