A congruence index for testing topological similarity between trees

Area of Science:

• Evolutionary biology
• Phylogenetics
• Computational biology

Background:

• Phylogenetic tree comparison is crucial in evolutionary biology.
• Current congruence statistics rely on computationally intensive simulations and evolutionary assumptions.
• A need exists for more efficient and assumption-free methods.

Purpose of the Study:

• To propose a novel index for testing topological congruence between phylogenetic trees.
• To offer a straightforward and computationally efficient alternative to existing methods.
• To provide a reliable measure of tree similarity with an associated confidence level.

Main Methods:

• The proposed index, I(cong), is based on maximum agreement subtrees (MAST).
• It allows for the comparison of trees with any number of leaves.
• The method does not require parametrization of evolutionary event likelihoods.

Main Results:

• The index I(cong) offers a simple and direct measure of topological congruence.
• It provides an associated confidence level for hypothesis testing.
• The method is computationally less demanding than traditional simulation-based approaches.

Conclusions:

• The new index provides a valuable tool for phylogenetic tree comparison.
• Its ease of use and computational efficiency make it widely applicable.
• An online tool is available for rapid computation of the index and P-value.