SCIENCE

                                    A single drop of blood helps clone a mouse

Tokyo Scientists have for the first time cloned a mouse from a single drop of blood.

Researchers used circulating blood cells collected from the tail of a donor mouse to produce the clone. 

The female mouse cloned from a peripheral leukocyte proved to be fertile by natural mating, and lived for a normal lifespan, researchers said. 

Researchers at the RIKEN Center for Developmental Biology in Kobe, Japan, devised a technique to avoid the diminishing returns of recloning the same cell. 

Success rates increased from the standard 3% in first-generation clones to 10% in first-generation and 14% in higher-generation clones, researchers said. 

The type of somatic cell used for this process is critical and depends largely on its efficiency in producing live clones, as well as its ease of access and readiness for experimental use. 

While cumulus cells, which surround oocytes in the ovarian follicle and after ovulation, are currently the preferred cell type, Dr Satoshi Kamimura, Atsuo Ogura, and colleagues questioned whether white blood cells (or leukocytes) collected from an easily accessed site, such as a tail, would be effective donor cells. Such cells would allow for repeated sampling with minimal risk to the donor mouse. 

There are five different types of white blood cells and, as expected, the researchers found that lymphocytes were the type that performed the most poorly: only 1.7% of embryos developed into offspring.