1. Initiative for Bioinformatics and Evolutionary Studies (IBEST), University of Idaho, Moscow, ID 83844-3051, USA
2. Department of Biological Sciences, Life Sciences South, Rm. 441A, University of Idaho, Moscow, ID 83844-3150, USA
3. Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201-1559, USA
4. Department of Mathematics, University of Idaho, Moscow, ID 83844-3051, USA
5. Department of Statistics, University of Idaho, Moscow, ID 83844-3051, USA