[1] Univ Rochester, Ctr Aging & Dev Biol, Sch Med & Dent, Rochester, NY 14642 USA
[2] Univ Rochester, Sch Med & Dent, Ctr Funct Genom, Rochester, NY 14642 USA
[3] Univ Rochester, Sch Med & Dent, Dept Environm Med, Rochester, NY 14642 USA
[4] UCL Royal Free & UCL Med Sch, Dept Paediat & Child Hlth, London WC1E 655, England
[5] NHGRI, NIH, Bethesda, MD 20892 USA
[6] Univ Rochester, Sch Med & Dent, Dept Biochem & Biophys, Rochester, NY 14642 USA