[1] Vienna Bioctr, Res Inst Mol Pathol, A-1030 Vienna, Austria
[2] Univ Vienna, Inst Bot, A-1030 Vienna, Austria
[3] Univ Kaiserslautern, Inst Human Biol, D-67663 Kaiserslautern, Germany
[4] MRC, Mouse Genome Ctr, Harwell OX11 0RD, Oxon, England
[5] MRC, Mammalian Genet Unit, Harwell OX11 0RD, Oxon, England
[6] INSERM, U406, F-13385 Marseille 5, France