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Recognizing the forest for the trees: testing temporal patterns of cladogenesis using a null model of stochastic
K Wollenberg1, J Arnold, J C Avise
1Department of Genetics, University of Georgia, Athens 30602, USA. wollenberg@bscr.uga.edu
Molecular Biology and Evolution
|July 1, 1996
Summary
Computer simulations reveal evolutionary branching patterns. By comparing simulated phylogenetic trees to real data, scientists can identify recent or ancient species radiations and assess evolutionary history significance.
Area of Science:
- Evolutionary Biology
- Phylogenetics
- Computational Biology
Background:
- Phylogenetic trees represent evolutionary history, but assessing the statistical significance of branching patterns requires null models.
- Existing methods for analyzing temporal patterns in phylogenies often lack robust null models for comparison.
- Understanding species radiation events is crucial for evolutionary biology.
Purpose of the Study:
- To develop and apply computer simulations of phylogenetic processes under a null model of lineage bifurcation and extinction.
- To compare simulated phylogenetic trees with empirical data from extant species to detect non-random branching patterns.
- To provide statistical tools and data for assessing the significance of temporal cladogenetic patterns in evolutionary trees.
Main Methods:
- Construction of Markovian models for phylogenetic processes, simulating lineage bifurcation and extinction.
- Calculation of cumulative distribution functions (CDFs) for branching times in simulated phylads.
- Comparison of simulated CDFs with empirical phylogenetic trees using the Kolmogorov-Smirnov test statistic (D).
Main Results:
- Molecular phylogenies for columbine plants and avian cranes showed significant deviations from null expectations, indicating recent and ancient radiations, respectively.
- The Drosophila virilis species group phylogeny did not exhibit significant historical clustering of branching events.
- Outgroup choice and phylogenetic frame of reference predictably influenced analytical conclusions for columbine phylogenies.
Conclusions:
- The developed null model and simulation approach effectively detect non-random temporal patterns in phylogenetic trees.
- Empirical phylogenies can significantly depart from stochastic expectations, revealing distinct patterns of species radiation.
- The provided tables of mean CDFs and probabilities serve as a valuable resource for statistical testing in evolutionary tree analysis.