Genome Science and Technology Graduate Program, University of Tennessee-Oak Ridge National Laboratory, Knoxville, Tennessee, United States of America.|Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America.|Genome Science and Technology Graduate Program, University of Tennessee-Oak Ridge National Laboratory, Knoxville, Tennessee, United States of America.|European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom.|Genome Science and Technology Graduate Program, University of Tennessee-Oak Ridge National Laboratory, Knoxville, Tennessee, United States of America.