Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 and U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA, 94598 USA.|Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 and U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA, 94598 USA.|Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 and U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA, 94598 USA.|Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 and U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA, 94598 USA.|Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 and U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA, 94598 USA.|Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 and U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA, 94598 USA.