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Cloning Animals
In Biology, cloning refers
to the creation of genetically identical copies of molecules, cells, or
organisms. Although cloning is often considered a recent scientific
development, animal cloning experiments have been conducted since the 1950s.
Furthermore, cloning occurs naturally in some invertebrates and vertebrates,
and is referred to as parthenogenesis (a form of asexual reproduction). Cellular cloning involves
the replication of entire cells in order to derive a cell population from a
single cell. This process can be surprisingly simple in unicellular
organisms such as bacteria and yeast, but can be a much more arduous and
complex process in higher organisms. Organism cloning refers to producing a
cellular organism that is genetically identical to another. Of these only three lambs were born, with only one, Dolly
surviving. In 2003, Dolly developed a progressive lung disease and was put
down following veterinary advice. Concerns have been raised that cloning
from adult cells essentially creates a clone that is the same biological age
at birth. This means that the cloned organism will age much more quickly
than a natural variant and it is argued will be more susceptible to disease. Since Dolly was successfully cloned, many other large mammals, including horses and bulls have been cloned, with cloning considered a promising tool for preserving endangered species. In 2001, the first clone of an endangered gaur (wild ox) was born. Noah was produced by fusing skin cells from a gaur that had died in 1993 with a cow’s ovum, which had been stripped of its genetic material. Unfortunately, Noah died after just forty-eight hours after contracting a common bacterial infection. Since this time, successful clones have been produced of African wild cats, demonstrating the possibility of repopulating endangered (or extinct) species, although this raises serious ethical and practical difficulties. If extinction or species
endangerment occurred from loss of habitat or lack of resources, cloning
does nothing to solve these issues and may even divert funds from
conservation projects. Conservationists also highlight the fact that cloning
does not alleviate problems of loss of genetic diversity due to inbreeding,
and that the success rate of the technology is so low at present, that
cloning should only be considered an experimental science. |