To clone or not to clone - large or small dog breeds?

Cloning is described as the process of making a genetically identical copy of an organism. In dogs this can be achieved through a technique called somatic cell nuclear transfer (SCNT). SCNT is a technique used by scientists where the nucleus of a body cell (somatic cell) is removed and transplanted into an enucleated egg cell (oocyte)[i]. The benefits of cloning in dogs could be seen in services that use dogs in their daily work e.g. Customs. However, to date progress in using this technique in dogs has been slow.

In 2005 one Afghan hound was successfully cloned by a research group in South Korea[ii]. Donor nuclei from adult skin cells of a three year old male of this large-breed were used. Only two out of 1095 embryos were maintained through to full term, with only one puppy surviving. In 2007, this technique again proved successful with the cloning of three female dogs using donor cells from the same large-breed[iii].

The research group then questioned whether the same technique could be used to clone a small-breed dog using somatic cells from an aged dog (in this case a 14 year old toy-poodle)[iv]. From 358 embryos that were surgically transferred into the surrogate dogs, only one pregnancy lasted full-term.

These results highlight that even though a large number of embryos result in an extremely small number of viable offspring, different breeds and sizes of dogs are successfully being cloned. This may make some dog owners take notice......

Genevieve Payne

VET I, 2008

References

[i] Wilmut, I., Beaujean, N., de Sousa, P.A., Dinnyes, A., King, T.J., Paterson, L.A., Wells, D.N.,
Young, L.E., 2002. Somatic cell nuclear transfer. Nature 419, 583-586.

[ii] Lee, B.C., Kim, M.K., Jang, G., Oh, H.J., Yuda, F., Kim, H.J., Shamim, M.H., Kim, J.J., Kang,
S.K., Schatten, G., Hwang, W.S., 2005. Dogs cloned from adult somatic cells. Nature 436, 641.

[iii] Jang, G., Kim, MK., Oh, HJ., Hossein, M.S., Fibrianto, Y.H., Hong, S.G., 2007. Birth of viable female dogs produced my somatic cell nuclear transfer. Theriogenology 67, 941-947.

[iv] Jang, G., Hong, S.G., Oh, H.J., Kim, M.K., Park, J.E., Kim, H.J., Kim, D.Y., Lee, B.C., 2008. A cloned toy poodle produced from somatic cells derived from an aged female dog. Theriogenology 69, 556-563.

Recent Related News Articles:

Associated Press, 2008. Drug-Sniffing Dogs Cloned in Korea. National Geographic; 24 April 2008. http://news.nationalgeographic.com/news/2008/04/080424-AP-clones.html. Accessed 25 May 2008.