1. Section of Integrative Biology and Institute of Cellular and Molecular Biology, The University of Texas at Austin, 1 University Station C0930, Austin, Texas 78712 USA;
2. DOE Joint Genome Institute and Lawrence Berkeley National Laboratory, 2800 Mitchell Drive, Walnut Creek, California, 94598 USA;
3. Department of Integrative Biology, University of California, 3060 Valley Life Sciences Building #3140, Berkeley, California 94720 USA;
4. Genome Project Solutions, 1024 Promenade Street, Hercules, California 94547 USA