Wednesday, November 5, 2008
Cloning of Extinct Species?
Scientists working at the RIKEN Research Institute in Japan recently cloned mice, frozen for more than a decade and whose cells had burst, using the Somatic Cell Nuclear Transfer technique, and prompting speculation that nuclear transfer might be used to “resurrect” extinct species.
Somatic Cell Nuclear Transfer involves transplanting the nucleus from a somatic cell (any cell of the body other than a reproductive cell) into an egg cell.
“In this process, the nucleus of a somatic cell is removed and inserted into an unfertilized egg that has had its nucleus removed. The egg with its donated nucleus... divides until it becomes an embryo[, which] is then placed inside a surrogate mother [to] develop…” (http://biology.about.com/od/biotechnologycloning/a/aa062306a.htm).
Typically cells burst when frozen, damaging the DNA inside them. The article explains that “[c]hemicals called cryoprotectants can prevent this, but they must be used before the cells are frozen.” Because the cloned mice had damaged cells, and a cryoprotectant had not been used, the Japanese research team speculates that nuclear transfer might be used on other organisms frozen for long periods without cryopreservation (for example, to resurrect extinct species like mammoths, who have often been found preserved in ice). They further believe that the technique might be used to preserve endangered species.
The team reported in the Proceedings of the National Academy of Sciences. Here’s the link to the article: http://www.newsdaily.com/stories/tre4a26nv-us-clones-frozen/