[1] Mid Sweden Univ, FMI Phys & Math Dept, S-85170 Sundsvall, Sweden
[2] Washington Univ, Inst Biomed Comp, St Louis, MO 63110 USA
[3] Univ Canterbury, Christchurch 1, New Zealand
[4] Massey Univ, Dept Comp Sci, Palmerston North, New Zealand
[5] Massey Univ, Inst Mol BioSci, Palmerston North, New Zealand