In a Scientific First, Mouse is Cloned From a Single Drop of Blood

Scientists clone mouse from a single drop of peripheral blood
Image Ashley Seifert / University of

Anyone who paid attention during high school biology knows that each cell within a biologic structure contains the entire genetic blueprint of the organism. However, while such a lesson is easy to retain and later regurgitate, grasping its actual implications is quite a different story. Just like astronomical distances and large numbers, basic genetics can be deceptively terse — and all too often, we forget the mind-boggling principles they actually denote.

The latest advancement in cloning research may perhaps serve as a reminder of this. According to the journal Biology of Reproduction, scientists have successfully cloned a donor mouse from a single droplet of blood collected from its tail. While all cloning occurs on a minuscule level, the new research shows that even a peripheral white blood cell collected from an easily accessed site is sufficient to achieve a success rate of two percent. For this reason, the new technique can stack up to older, more invasive methods, where the standard rate is around three percent.

The findings are part of a research program focusing on the development of more effective methods of cloning. It can take a team of scientists several years to develop a strain of mouse with the genetic mutations required for their research model — and if a generation is found to be infertile, the only option left is cloning.

Genetic copies of mouse strains are generated through somatic-cell nuclear transfer (SCNT) — a tremendously complex process whereby a denucleated egg cell is fused with the nucleus of a somatic cell extracted from a donor. In 1996, an early version of SCNT generated the world’s first mammal clone, Dolly the sheep.

Currently, the preferred type of cell is cumulus cells, which cluster around the oocyte in the ovarian follicle. However, Drs. Satoshi Kamimura, Atsuo Ogura and colleagues at the RIKEN BioSource Center in Tsukuba, Japan questioned whether other, more easily accessed cells could be substituted. Sampling of peripheral cells, such as white blood cells, would drastically reduce risks for the donor otherwise associated with the procedure.

The research at the RIKEN center tested five different kinds of white blood cells, or leukocytes. Scientists found that within this set, the nuclei of the physically largest types — granulocytes and monocytes — yielded the highest success rate.While the success rate failed to surpass that of the preferred cumulus cell, the findings represent a significant step towards lowering the risk for donors when preserving a valuable strain of mouse.

Sometimes, all it takes is a single drop.

Source: Kamimura S, Inoue K, Ogonuki N, Hirose M, Oikawa M, Yo M, Ohara O, Miyoshi H, Ogura A. Mouse cloning using a drop of peripheral blood.Biol Reprod2013

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