LONDON — The ability of adult stem cells to differentiate and proliferate into different cell types has been questioned by research published last week indicating that they might simply fuse with existing cells, creating genetically mixed, tetraploid cells.
A group working at the University of Edinburgh tracked the fate of fluorescent markers in mouse brain cells that were co-cultured with embryonic stem cells. Initial examination indicated that the adult brain cells had reverted to the less specialized status of the undifferentiated stem cells around them. However, the new cells were found to carry a transgenic marker and chromosomes derived from the embryonic stem cells. Genetic analysis confirmed that these new cells actually resulted from the merging of two cell types, so that they had twice the usual number of chromosomes. This suggested that rather than developing into new cell types, the cells were a genetic mix of the two cell ...
