Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.|Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA.