[1] Univ Pittsburgh, Ctr Vaccine Res, Pittsburgh, PA 15260 USA
[2] Univ Pittsburgh, Dept Microbiol & Mol Genet, Pittsburgh, PA 15260 USA
[3] Univ Calif Los Angeles, Ctr Neurobehav Genet, Semel Inst Neurosci & Human Behav, Los Angeles, CA 90024 USA
[4] Univ Free State, Dept Genet, Fac Nat & Agr Sci, Bloemfontein, South Africa
[5] Univ Manchester, Dept Computat & Evolutionary Biol, Fac Life Sci, Manchester M13 9PL, Lancs, England
[6] Univ Vermont, Dept Pathol, Burlington, VT 05405 USA
[7] Univ Vermont, Dept Biochem, Burlington, VT 05405 USA
[8] Univ Pittsburgh, Dept Pathol, Pittsburgh, PA 15260 USA