[1] Univ Sheffield, Dept Biomed Sci, Sheffield S10 2TN, S Yorkshire, England
[2] Univ Sheffield, Ctr Stem Cell Biol, Sheffield S10 2TN, S Yorkshire, England
[3] Univ So Calif, Keck Sch Med, Eli & Edythe Broad Ctr Regenerat Med & Stem Cell, Los Angeles, CA 90033 USA
[4] Lund Univ, Lund Strateg Res Ctr Stem Cell Biol & Cell Therap, SE-22184 Lund, Sweden
[5] Weatherall Inst Mol Med, Mol Haematol Unit, Oxford OX3 9DS, England
[6] Lund Univ, Dept Theoret Phys, SE-22362 Lund, Sweden