PhylogeneticNode.php
Immutable value object describing one node of a phylogenetic tree Freely inspired by BioPHP's project biophp.org Created 30 September 2026 Last modified 8 October 2026
Table of Contents
Classes
- PhylogeneticNode
- A leaf is a node with no children and must carry a name (the taxon it represents) ; an internal node commonly has no name, since Newick and neighbor-joining rarely name ancestral nodes. Branch length is the distance to this node's OWN parent, so it is meaningless - and left null - on the root of a tree. Negative branch lengths are accepted without validation : neighbor-joining can legitimately produce one when the input distances are slightly non-additive (measurement noise), a well documented property of the algorithm, not an error this value object should reject.