Comparing bootstrap and posterior probability values in the four-taxon case.

Area of Science:

• Phylogenetics and Evolutionary Biology
• Computational Biology and Bioinformatics

Background:

• Assessing phylogenetic hypothesis reliability is crucial in phylogenetic analysis.
• Nonparametric bootstrap has been the historical standard for evaluating phylogenetic relationships.
• Bayesian methods now express clade support using posterior probabilities.

Purpose of the Study:

• To explore the relationship between nonparametric bootstrap values and Bayesian posterior probabilities.
• To investigate these relationships using simulated data and the four-taxon case.

Main Methods:

• Simulated data generation for phylogenetic analysis.
• Inference of phylogenetic trees using maximum likelihood (for bootstrap) and Bayesian methods (for posterior probabilities).
• Comparative analysis of bootstrap values and posterior probabilities across different tree topologies.

Main Results:

• A complex association exists between bootstrap values and posterior probabilities.
• Three distinct regions in tree space show varying degrees of significant differences between the two measures.
• Posterior probability values were found to be excessively high compared to theoretical expectations and bootstrap values.

Conclusions:

• Direct extrapolation from single topology studies is unreliable for generalizing the bootstrap-posterior probability relationship.
• The findings support previous research indicating inflated posterior probability values.
• Understanding these differences is vital for accurate phylogenetic reliability assessment.