Ishiuchi and his colleague, Shogo Matoba of the RIKEN BioResource Research Center, hope their animal-cloning approach will support wildlife conservation efforts, particularly for endangered species with only a few remaining individuals. However, cloning has many applications, ranging from scientific breakthroughs to ethically controversial uses.
No discussion of animal cloning would be complete without mentioning Dolly. Born in 1996, Dolly was the first mammal successfully cloned from an adult cell. Scientists removed the nucleus from an egg cell and replaced it with the DNA-containing nucleus of an adult mammary-gland cell. The resulting embryo was implanted into a surrogate sheep, producing Dolly, a genetic copy of the DNA donor.
The researchers behind Dolly’s creation were interested in genetically modifying livestock. Farmers have used selective breeding to develop desirable traits for thousands of years, but cloning allows scientists to produce genetic replicas of animals with valuable characteristics.
Animal cloning has also been used to duplicate deceased pets, including pets owned by celebrities such as Barbra Streisand and Tom Brady. For tens of thousands of dollars, commercial cloning companies can collect cells from a deceased or living pet and use them to create a genetically identical animal.
However, not everyone supports pet cloning. Critics point out that the procedure offers no clear medical or environmental benefit and requires egg cells from donor animals as well as surrogate animals to carry the pregnancies. Bioethicist Jessica Pearce explained that this aspect of dog cloning amounts to the “exploitation of the canine underclass.”
When it comes to wildlife conservation, the case for cloning is stronger. Supporters argue that cloning could help preserve genetic diversity and restore endangered animal populations when only a small number of individuals remain.
Scientists have preserved animal tissue for decades in specialized frozen collections known as “cryozoos.” The San Diego Zoo Wildlife Alliance’s Frozen Zoo, for example, contains more than 1,300 cell types, including samples collected many years ago. These frozen cells could become an important resource for future genetic-preservation and species-conservation programs.
Source: www.technologyreview.com