The Exelixis Lab

Enabling Research in Evolutionary Biology

Our Mission - Enable Research in Evolutionary Biology

Our focus is on the evolution of hardware and parallel computer architectures as well as on the evolution of molecular sequences.

We understand Bioinformatics as a discipline that develops algorithms, models, and tools that help Biologists to generate new biological insights and knowledge. We try to bridge the gap between the world of systematics and the world of high performance computing.

Due to the increasing descrepancy between the pace of molecular data accumulation and increase in CPU speeds (which is much slower), which we call the "Bio-Gap" we feel that the time has come to establish parallel computing as standard technique in Bioinformatics.

2020 summer school on computational molecular evolution

Applications are now open for the 12th summer school on computational molecular evolution organized by Ziheng Yang, Cilia Antoniou, Adam Leache and Alexis Stamatakis. It will be held once again at the Hellenic Center for Marine Research near Heraklion, Crete, Greece.

See the course page for further details

New Software

ParGenes: massively parallel inference of gene trees

A tool for massively parallel model selection and phylogenetic tree inference on thousands of genes using thousands of cores, based on ModelTest-NG and RAxML-NG. Now published in Bionformatics and available for download here.

RAxML-NG Web-Server

The brand new web-server for the completely re-designed version of RAxML, called RAxML-NG is available here.

Complete re-design of Evolutionary Placement Algorithm

This is a completely re-designed version of our Evolutionary Placement Algorithm. It is at least 6 times faster than pplacer/EPA and has substantially improved parallel scalability.

It is available for download here

As before EPA-NG user support will be provided via the raxml google group.

Low Level Phylogenetic Likelihood Library version 2

This is version 2 of our low level phylogenetic likelihood library.

It now includes site repeats (see paper) to boost computations likelihood computations. It can be downloaded here and has been already integrated into RAxML-NG and Modeltest-NG (see below).

Completely re-designed Modeltest Software

We have completeley re-designed the famous Modeltest software. It's much faster, better, and more stable now.

The all new Modeltest can be downloaded here.

RAxML next generation

The new, from scratch re-implementation of RAxML is finally avaible at github.

It's faster, more stable, easier to use, and more scalable. application note

The low-level phylogenetic likelihood library: libpll

libpll is a new library that facilitates phylogenetic analyses. Libpll is a low-level re-design of our previous PLL, that offers unprecedented flexibility when implementing new models, testing hypotheses and/or developing new tools, methods or pipelines.

Apart from the highly-optimized phylogenetic likelihood function, libpll offers the following functionality:

  • parsing of alignment file formats (FASTA/PHYLIP)
  • parsing of tree file formats (binary rooted, unrooted, n-ary trees)
  • flexibility in defining custom models of dna evolution
  • support for heterotachous and mixture models
  • support for models with arbitrary number of states
  • parsimony functions
  • support for arbitrary number of rate heterogeneity categories
  • functions for weighted parsimony
  • methods for ascertainment bias correction
  • tree visualization

Libpll is highly optimized and can make use of the SSE3/AVX/AVX-2 instruction sets. It is available for download here under the Affero GPL 3 License.

The corresponding documentation can be found here and a large porton of its functionality is presented the following examples.

MPTP: faster and more accurate species delimitation code

This tool is a significant improvement of our previous PTP tool for single-locus species delimitation. It is significantlky faster, more accurate, and more scalable with respect to the number of taxa.

The methods are described in this preprint, the code can be downloaded here, and there also is a web-service.


The latest version of RAxML can be found at Alexis github repository.

RAxML questions, help & bug reports: please use the RAxML google group

There is finally a new manual available for RAxML version 8.1.X. You can get it here

Students from KIT

We are always looking for student programmers (HiWis) and students interested in doing bachelor/master theses projects with us. If you are interested please send an email to Alexis at Alexandros dot Stamatakis at h hyphen its dot org

New Papers

Our 5 Most Recent Papers

  1. Dora Serdari, Evangelia-Georgia Kostaki, Dimitrios Paraskevis, Alexandros Stamatakis, Paschalia Kapli​, "Automated, phylogeny-based genotype delimitation of the Hepatitis Viruses HBV and HCV", PeerJ, 7:e7754, open access, 2019.
  2. Paula Breitling, Ben Bettisworth, Lukasz Reszczynski, Olga Chernomor, Alexandros Stamatakis, "Empirical Analysis of Phylogenetic Quasi-Terraces", bioRxiv, 810309, 2019, preprint.
  3. Nicolas Comte, Benoit Morel, Damir Hasic, Laurent Guéguen, Bastien Boussau, Vincent Daubin, Simon Penel, Celine Scornavacca, Manolo Gouy, Alexandros Stamatakis, Eric Tannier, David P. Parsons, "Treerecs: an integrated phylogenetic tool, from sequences to reconciliations", bioRxiv, 782946, 2019, preprint.
  4. Benoit Morel, Alexey M. Kozlov, Alexandros Stamatakis, Gergely Szöllősi. "GeneRax: A tool for species tree-aware maximum likelihood based gene tree inference under gene duplication, transfer, and loss.", bioRxiv, 779066, 2019, preprint.
  5. Sarah Lutteropp, Alexey M. Kozlov, Alexandros Stamatakis. "A Fast and Memory-Efficient Implementation of the Transfer Bootstrap", bioRxiv, 734848, 2019, preprint.
All publications >>