Center for Complex Biological Systems and Department of Mathematics, University of California Irvine, Irvine, California, United States of America.|Center for Complex Biological Systems and Department of Mathematics, University of California Irvine, Irvine, California, United States of America.|Center for Complex Biological Systems and Department of Mathematics, University of California Irvine, Irvine, California, United States of America, Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, United States of America.