[1] UNIV HELSINKI,DEPT MED GENET,HAARTMANINKATU 3,SF-00290 HELSINKI 29,FINLAND
[2] UNIV AUTONOMA BARCELONA,FAC CIENCIAS,DEPT BIOL ANIM,BARCELONA,SPAIN
[3] UNIV AUTONOMA BARCELONA,FAC CIENCIAS,DEPT VEGETAL & ECOL,UNIDAD ANTROPOL,BARCELONA,SPAIN
[4] HOSP CREU ROJA DE BARCELONA,UNIDAD HEMATOL & ONCOL,BARCELONA,SPAIN
[5] STATE UNIV LIMBURG,DEPT MOLEC CELL BIOL,6200 MD MAASTRICHT,NETHERLANDS
[6] STANFORD UNIV,MED CTR,SCH MED,DEPT GENET,STANFORD,CA 94305