[1] UNIV SUSSEX,MRC,CELL MUTAT UNIT,BRIGHTON BN1 9RR,ENGLAND
[2] CHILDRENS HOSP,HOWARD HUGHES MED INST,BOSTON,MA 02115
[3] HARVARD UNIV,SCH MED,DEPT GENET,BOSTON,MA
[4] UNIV CAMBRIDGE,WELLCOME CRC INST,CAMBRIDGE CB2 1QR,ENGLAND
[5] UNIV CAMBRIDGE,DEPT ZOOL,CAMBRIDGE CB2 1QR,ENGLAND