1. Rice University Department of Computer Science, , Houston 77005, TX, USA
2. Rice University Department of Computer Science, , Houston 77005, TX , USA
3. University of Edinburgh MRC Institute of Genetics and Cancer, , Edinburgh EH4 2XU , UK
4. University of Houston Department of Biology and Biochemistry, , Houston 77004, TX , USA
5. Freie Universität Berlin Department of Physics, , Berlin 14195 , Germany
6. Institute of Biosciences, Federal University of Rio Grande do Sul Department of Biophysics, , Porto Alegre 91501-970 , Brazil