Production of a cloned mouse by nuclear transfer from a fetal fibroblast cell of a mouse closed colony strain

We have tested a closed colony mouse strain as a source for nuclei donors to determine differences in cloning efficiency. When donor nuclei were isolated from fetal fibroblast cells and injected into recipient oocytes from closed colony mice (ICR), reconstructed oocytes developed to full term and the success rate of cloning was 0.1%, This result indicates that cloning efficiency does not depend on the cell type. The body weight of the cloned mouse was lighter than controls, and the lifetime of the cloned mouse was the average for a mouse. These results contradict commonly-held views on cloning.