Institution: | (1) Institut de Génétique et Microbiologie, Université Paris-Sud, Unité Associé an CNRS 1354, 91405 Orsay Cedex, France;(2) Department of Biology, University of Essex, CO4 SQ Wivenhoe Park, Colchester, UK;(3) Present address: Department of Genetics, University of Adelaide, GPO Box 498, Adelaide, Australia;(4) Present address: Division of Communicable Diseases, Clinical Research Centre, Northwick Park Hospital, HA1 3UJ Harrow, Middlesex, UK |