Department of Ecology and Evolutionary Biology Department of Computer Science, Brown University, Providence, RI, USA.|Department of Computer Science, Brown University, Providence, RI, USA.|Computer Science Department, Wellesley College, Wellesley, MA, USA.|Department of Ecology and Evolutionary Biology Center for Computational Molecular Biology, Brown University, Providence, RI, USA.|Department of Ecology and Evolutionary Biology Center for Computational Molecular Biology, Brown University, Providence, RI, USA.