[1] Univ Calif San Diego, Dept Bioengn, La Jolla, CA 92093 USA
[2] Univ Pittsburgh, Inst Canc, Sch Med, Dept Computat Biol, Pittsburgh, PA 15261 USA
[3] Univ Pittsburgh, Grad Sch Publ Hlth, Dept Human Genet, Pittsburgh, PA 15261 USA
[4] Univ Pittsburgh, Grad Sch Publ Hlth, Dept Biostat, Pittsburgh, PA 15261 USA
[5] Washington Univ, Sch Med, Dept Genet, St Louis, MO 63110 USA