Journal Article
RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogenies
Alexandros Stamatakis•2014
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34,988 citations · Molecular Biology
Open Access

TLDR

This updated computer program can study much larger collections of biological sequences faster, use less memory, test tree reliability, and help researchers examine or classify genetic data.

Summary

1 Study Aim

The study aims to describe major extensions to RAxML (Randomized Axelerated Maximum Likelihood), a program for phylogenetic analysis (reconstructing evolutionary relationships). The author focuses on supporting larger datasets, more data types, faster calculations, lower memory use, and broader analysis of completed evolutionary trees. The paper also documents new tools for sequencing data and explains available user support. The study presents a more capable program for building and examining evolutionary trees.

2 Study Design

This software-development paper reviews RAxML’s new functions rather than testing a biological sample. The author describes bootstrap methods (resampling data to measure tree support), substitution models (rules for sequence change), and binary, morphological, and RNA data options. RAxML supports parallel computing through PThreads and MPI (Message Passing Interface). It also provides tree comparisons, consensus trees, rogue-taxon detection, and EPA (Evolutionary Placement Algorithm) read placement. A small DNA benchmark compares unoptimized, SSE3, and AVX processor instructions. The work updates software with broader inputs, faster processing, and many tree-analysis tools.

3 Findings

The study reports four bootstrap approaches, including automatic stopping when support stabilizes. RAxML adds more protein models, ascertainment-bias correction (adjusting for omitted constant sites), and automatic model selection. It supports parallel searches, reduced-memory analyses, ancestral-state estimates, tree rooting, and quartet calculations. Post-analysis includes Robinson–Foulds distances (tree-topology differences), consensus trees, and Tree Certainty measures. Evolutionary placement can assign short reads or fossils to reference trees. In the benchmark, SSE3 reduced runtime from 111.5 to 84.4 seconds, while AVX reduced it to 66.22 seconds. The author recommends ExaML for extremely large supercomputer analyses. The update makes large evolutionary studies faster, broader, and easier to evaluate.

Abstract

Abstract Motivation: Phylogenies are increasingly used in all fields of medical and biological research. Moreover, because of the next-generation sequencing revolution, datasets used for conducting phylogenetic analyses grow at an unprecedented pace. RAxML (Randomized Axelerated Maximum Likelihood) is a popular program for phylogenetic analyses of large datasets under maximum likelihood. Since the last RAxML paper in 2006, it has been continuously maintained and extended to accommodate the increasingly growing input datasets and to serve the needs of the user community. Results: I present some of the most notable new features and extensions of RAxML, such as a substantial extension of substitution models and supported data types, the introduction of SSE3, AVX and AVX2 vector intrinsics, techniques for reducing the memory requirements of the code and a plethora of operations for conducting post-analyses on sets of trees. In addition, an up-to-date 50-page user manual covering all new RAxML options is available. Availability and implementation: The code is available under GNU GPL at https://github.com/stamatak/standard-RAxML. Contact: [email protected] Supplementary information: Supplementary data are available at Bioinformatics online.