Program in Computational Biology and Bioinformatics, Duke University, 101 Science Dr, Durham, 27708, USA.|Department of Biostatistics and Bioinformatics, Duke University, 2424 Erwin Rd, Durham, 27708, USA.|Department of Biostatistics and Bioinformatics, Duke University, 2424 Erwin Rd, Durham, 27708, USA.|Program in Computational Biology and Bioinformatics, Duke University, 101 Science Dr, Durham, 27708, USA. asallen@duke.edu.