Evidence exists that bone marrow cells can transform into skeletal muscle and brain tissue. In the 4 May Cell Diane Krause and colleagues at Yale University School of Medicine, New Haven have for the first time identified a haematopoietic stem cell in mice that can transform into virtually any cell type.

Krause et al transplanted bone marrow haematopoietic stem cells from adult male mice into irradiated female mice, and then tested for the presence of Y chromosomes in various tissue specimens from the female mice. Long-term repopulation analysis of irradiated hosts showed evidence of the cell's progeny not only in blood and bone marrow but also in tissue from the skin, liver, large and small intestine, stomach, oesophagus and lung (Cell 2001, 105:369-377).

CD34 and SCA-1 expression is uniquely increased in these rare cells during their homing in the adult male mice bone marrow. Researchers believe that...