1. Plant Sciences Institute, Iowa State University, Ames, Iowa 50011
2. MSU-DOE Plant Research Laboratories, Department of Plant Biology, East Lansing, Michigan 48824
3. Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011
4. Department of Statistics, Iowa State University, Ames, Iowa 50011
5. Genome Informatics Facility, Iowa State University, Ames, Iowa 50011
6. Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina 28403