30 May 2007

Cloning the dead


Animal species become endangered everyday, due to factors such as habitat destruction and over hunting. These threats can lead to the decrease in populations and the eventual extinction of species. Scientists are now applying cloning as a tool to increase population sizes and possibly conserve endangered species.

Cloning is the process of making a genetically identical copy of an individual. The type of cloning which has been applied to endangered species is somatic cell nuclear transfer (SCNT). In SCNT, the nucleus is removed from a somatic cell of the individual to be cloned. The nucleus of the somatic cell is then fused with an egg cell (from the individual that is to be the surrogate mother) which has had its own nucleus removed, to create a single cell clone. When the single cell clone reaches the blastocyst stage it can be inserted into the surrogate mother for gestation.

Interspecies SCNT has been used successfully to create a mouflon lamb, an endangered species of wild sheep. Researchers removed the nuclei from the cells of two female mouflons which had died earlier in the day. The nuclei were then fused with enucleate egg cells of domestic sheep and were implanted in four domestic ewes. One of the ewes completed gestation and gave birth to a cloned mouflon lamb. The mouflon lamb contained DNA from both species. The genomic DNA was identical to the original mouflon, while the mitochondrial DNA came from the domestic sheep.

The successful cloning of the mouflon using interspecies SCNT demonstrated that cloning may be a potential technique to increase populations of wildlife and assist in the conservation of endangered species.


References

Primary
Loi, P., et al. 2001. Genetic rescue of an endangered mammal by cross-species nuclear transfer using post-mortem somatic cells. Nature Biotechnology 19(October):962-964.
http://www.nature.com.ezproxy.library.uq.edu.au/nbt/journal/v19/n10/pdf/nbt1001-962.pdf

Secondary

Scientists Clone First Endangered Species: a Wild Sheep
http://news.nationalgeographic.com/news/2001/10/1025_TVsheepclone.html
Wildlife conservation and reproductive cloning
http://www.reproduction-online.org/cgi/content/full/127/3/317

Mouflon
http://en.wikipedia.org/wiki/Mouflon



Lauren McGrath 41211948

at 5/30/2007 05:34:00 pm