[1] Duke Univ, Dept Biol, Program Genet & Genom, Durham, NC 27708 USA
[2] Univ N Carolina, Carolina Ctr Genome Sci, Curriculum Genet & Mol Biol, Chapel Hill, NC 27599 USA
[3] Joint Genome Inst, Walnut Creek, CA 94598 USA
[4] Univ N Carolina, Dept Microbiol & Immunol, Carolina Ctr Genome Sci, Curriculum Genet & Mol Biol, Chapel Hill, NC 27599 USA
[5] Duke Univ, Dept Biol, Inst Genome Sci & Policy, Durham, NC 27708 USA