Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA. thomas.royce@yale.edu <thomas.royce@yale.edu>|Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA. thomas.royce@yale.edu <thomas.royce@yale.edu>|Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA. thomas.royce@yale.edu <thomas.royce@yale.edu>