[1] Carnegie Inst Sci, Dept Plant Biol, Stanford, CA 94305 USA
[2] Wellcome Trust Sanger Inst, Cambridge CB10 1SA, England
[3] Princeton Univ, Carl Icahn Lab, Lewis Sigler Inst Integrat Genom, Princeton, NJ 08544 USA
[4] Wayne State Univ, Dept Comp Sci, Detroit, MI 48202 USA