1. Department of Genetics, Cellular and Developmental Biology, Iowa State University, Ames, IA 50011, USA
2. Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA 50011, USA
3. Department of Statistics, Iowa State University, Ames, IA 50011, USA
4. Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA