Cloning for conservation

Cloning is the process in which genetic material (DNA) is transferred from one organism to a host cell in another. With this technology, scientists can transfer anything from single genes to entire genomes between host organisms.

In the wider science communities, cloning has applications in isolating and propagating desirable genes for medication and research, and furthermore in cloning entire organisms for a range of purposes.

Whilst natural breeding will always represent the preferred method for re-populating species, the state of wild populations may not allow for this activity. Even more modern approaches to genetic management, such as artificial insemination, may be insufficient to prevent the world’s most critically endangered species from succumbing to extinction, often stemming from inbreeding depression.

Inbreeding depression results from the mating of genetically similar (i.e. related) individuals and is a symptom of small populations. It is a potentially catastrophic phenomenon in which low genetic diversity as well as a potential accumulation of deleterious alleles can lead to declines and extinctions in animal populations.

Cloning is uniquely positioned to mitigate inbreeding depression in small populations. Successful cloning projects can not only bolster population sizes but also increase genetic diversity.

In sexual reproduction, only half of each parent’s genetic information is passed on to any one offspring. For species that only have a few offspring in their lifetime, there is an increased chance that some of their DNA will never be passed on. In large populations, a net loss of genetic variation is prevented by the introduction of new variation through processes such as mutation. This is not the case in smaller populations.

By releasing cloned individuals, scientists can offer a second opportunity for gene’s to be shared, therefore reducing the rate of variation loss. The DNA required for this cloning can be extracted from live or dead specimens and it is even possible to transfer genes between species.

To date, cloning has successfully resulted in healthy offspring in several endangered species and there is reason to believe that it will be a useful tool for future conservation breeding programs such as that of the Giant Panda.

Just this week, Brazilian scientists have announced their intentions to take a new approach in conservation orientated cloning. Their aim is to clone species such as the jaguar purely to supply captive institutions such as zoos. They argue that creating a separate pool of animals for this trade would reduce the collection of threatened populations from the wild.

Certainly, the ethical implications of cloning and captive breeding alone are contentious. Through combining these two approaches, the Brazilian scientists are attempting something highly controversial. Valid ethical concerns range from the low success rates and high costs of cloning to the implications of creating of wild animals destined for a life in captivity.

Counter arguments however, are that this scheme is for the greater good of species conservation, even if it is at the expense of a small number of individuals.

 

http://www.aseanbiodiversity.info/Abstract/51008743.pdf

http://www.vet.chula.ac.th/~tjvm/full_text/v41/413/pdf/41supplPDF/12%20%20TJVM_Review.pdf

http://www.scielo.cl/pdf/ijmorphol/v23n4/art08.pdf

http://www.reproduction-online.org/content/127/3/317.full

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