1. Department of Biology and Center for Molecular Signaling, Wake Forest University , Winston-Salem, NC 27109 , USA
2. Molecular Genetics and Genomics Graduate Program, Wake Forest School of Medicine , Winston-Salem, NC 27109 , USA
3. Department of Statistical Sciences, Wake Forest University , Winston-Salem, NC 27109 , USA
4. Department of Mathematics, Wake Forest University , Winston-Salem, NC 27109 , USA
5. Department of Mathematics and Statistics, Amherst College Current Address: , Amherst, MA 01002 , USA
6. Department of Biosystems, KU Leuven Current Address: , Leuven , Belgium
7. Department of Computer Science, Wake Forest University , Winston-Salem, NC 27109 , USA