differentiated stem cells,
Differentiated Cells May Be More Efficient Than Adult Stem Cells for Cloning
The result of a study in mice suggests that differentiated cells are more efficient than stem cells for animal cloning.
3 questions to Li-Ying Sung and Jerry Yang, co-authors of the report published in Nature Genetics.
Previous attempts by scientists to produce animal clones directly from fully differentiated cells had failed. What was it about your experiments  that allowed your animal clones to survive?
Li-Ying Sung: This could be attributed to various factors. Different cell types and different optimized cloning protocols were used. Our guess is this is because we used different cell types. However, we are still working to determine the exact factors.
You cast doubt on the hypothesis that Dolly was created from adult stem cells. Why?
Jerry Yang: We could not say specifically that Dolly is not created from adult stem cells, but our findings show convincingly that cloned animals like Dolly from the conventional cloning method could likely be derived from differentiated cells.
How do you believe your findings could affect future stem cell research and use?
Jerry Yang: Therapeutic cloning involves the combined technology of embryonic stem cell and cloning technology to create patient specific stem cells for potential therapy. Adult stem cells exist in most organs/tissues but in small fraction, and they are very difficult to isolate and can not cultured/maintained in culture to multiple without differentiation. If differentiated cells like blood cells, skin cells etc are ideal donors for nuclear transfer reprogramming as shown in our study, cell biopsy to receive and culturing the biopsied differentiated cells are easily doable as donor cells for therapeutic cloning. Sung L-Y et al, Nature Genetics (01 Oct 2006) Letters
the authors of the paper comment on their own results