Japanese researchers have successfully cloned a mouse using a small sample of peripheral white blood cells from the tail of a donor mouse.
The Riken BioResource Center team were trying to find a method of reproducing scientifically valuable strains of mice for research, such as those genetically engineered to become models of a human disease. However, such mice cannot necessarily reproduce successfully, and somatic-cell nuclear transfer (SCNT) – insertion of a cell nucleus from the valuable mouse into a mouse oocyte (egg cell) from which the nucleus has been removed - has been trialled in recent years.
Writing in the journal Biology of Reproduction, the researchers report that they extracted nuclei from specific types of white blood cell (granulocytes / monocytes) taken from live mice of four different strains (including genetically modified strains) and cloned them, resulting in the birth of normal-looking and apparently healthy offspring.
Comment: The type of donor cell used for cloning can affect success rates and the fitness of cloned offspring, but the scientists noted that ‘ease of access and noninvasiveness at cell collection’ were practical issues that might also affect the choice of cells – especially if there were only a single animal available as a cell source. This can be the case for strains produced by painstaking genetic manipulation, and so killing the animal in order to extract cells for cloning would be a very high-risk approach. This research therefore demonstrates a potentially very useful alternative.