RT Journal Article SR Electronic T1 Genesis and Gappa: Processing, Analyzing and Visualizing Phylogenetic (Placement) Data JF bioRxiv FD Cold Spring Harbor Laboratory SP 647958 DO 10.1101/647958 A1 Czech, Lucas A1 Barbera, Pierre A1 Stamatakis, Alexandros YR 2019 UL http://biorxiv.org/content/early/2019/12/01/647958.abstract AB We present GENESIS, a library for working with phylogenetic data, and GAPPA, an accompanying command line tool for conducting typical analyses on such data. The tools target phylogenetic trees and phylogenetic placements, sequences, taxonomies, and other relevant data types, offer high-level simplicity as well as low-level customizability, and are computationally efficient, well-tested, and field-proven.Availability and Implementation Both GENESIS and GAPPA are written in modern C++11, and are freely available under GPLv3 at http://github.com/lczech/genesis and http://github.com/lczech/gappa.Contact lucas.czech{at}h-its.org and alexandros.stamatakis{at}h-its.org.