1 Bioinformatics & Computational Biology, GenOmics, Bioinformatics & Translational Research Center, RTI International, Research Triangle Park, NC, United States. Electronic address: hpan@rti.org.
2 Bioinformatics & Computational Biology, GenOmics, Bioinformatics & Translational Research Center, RTI International, Research Triangle Park, NC, United States. Electronic address: chamilton@rti.org.