title: FOCUS: an alignment-free model to identify organisms in metagenomes using non-negative least squares.
abstract: One of the major goals in metagenomics is to identify the organisms present in a microbial community from unannotated shotgun sequencing reads. Taxonomic profiling has valuable applications in biological and medical research, including disease diagnostics. Most currently available approaches do not scale well with increasing data volumes, which is important because both the number and lengths of the reads provided by sequencing platforms keep increasing. Here we introduce FOCUS, an agile composition based approach using non-negative least squares (NNLS) to report the organisms present in metagenomic samples and profile their abundances. FOCUS was tested with simulated and real metagenomes, and the results show that our approach accurately predicts the organisms present in microbial communities. FOCUS was implemented in Python. The source code and web-sever are freely available at http://edwards.sdsu.edu/FOCUS.
authors.affiliation: Computational Science Research Center, San Diego State University , San Diego, CA , USA.
authors.forename: Genivaldo Gueiros Z
authors.initials: GG
authors.lastname: Silva
authors.affiliation: Computational Science Research Center, San Diego State University , San Diego, CA , USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Cuevas
authors.affiliation: Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, GA , Nijmegen , The Netherlands ; Department of Marine Biology, Institute of Biology, Federal University of Rio de Janeiro , Brazil.
authors.forename: Bas E
authors.initials: BE
authors.lastname: Dutilh
authors.affiliation: Computational Science Research Center, San Diego State University , San Diego, CA , USA ; Department of Computer Science, San Diego State University , San Diego, CA , USA ; Department of Biology, San Diego State University , San Diego, CA , USA ; Department of Marine Biology, Institute of Biology, Federal University of Rio de Janeiro , Brazil ; Division of Mathematics and Computer Science, Argonne National Laboratory , Argonne, IL , USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Edwards
keywords: Metagenomes; Modeling; k-mer