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Biology 103
2001 First Web Report
On Serendip

Is Cloning a Good Excuse?

Helena Salles

In the movie 'The 6th Day' (1), cloning (5) was the main issue. What caught my attention were the ads throughout the movie that made cloning a pet seem like a mundane aspect to life. After all, if a deceased pet's precise genetic information was kept, the clone created could not be much different. The question that remains is if the pet in question is indeed still the first one, with no memories of what happened before, or a new one. If that is the case, could we bring back extinct animals from their genetic information and make them exist again, despite evolution?

Bringing back extinct animals raise the shackles of many people, especially because they defy scientific and moral beliefs. With 'DNA zoos' (2) keeping the DNA of several extinct and endangered species, many people argue that this might only entice poachers to continue hunting down Government protected endangered species because they will never be extinguished.

Advanced Cell Technology (ACT) (3) explains the cloning (6) process as a nuclear transfer, where eggs are matured in a culture dish with the appropriate environment. Each egg has a remnant egg cell called the polar body, and is surrounded by a protective layer called the zona pellucida. While a pipette holds the egg still, researchers use a needle to extract chromosomes and the polar body from the egg, leaving only the zona pellucida and the empty egg. Meanwhile, isolated skin cells from the animals to be cloned (called fibroblasts) are matured in culture dishes. A single skin cell is then inserted below the surface of the zona pellucida by a needle, but still outside the boundaries of the egg cytoplasm. The injected egg is then exposed to an electric shock that fuses the egg cytoplasm and the skin cell together, which causes the skin cell's nucleus to enter the egg cytoplasm. The genes of the nucleus mesh with the egg as well, and in a few hours the fused cell begins the process of dividing itself.

A semi-successful example would be Dolly, despite her quickened aging process, that cloning animals are well within our grasp. However, there are many scientists that argue the validity of clones such as Dolly, because they were made from genetic material both from the adult cell they were taken from, and from the egg that was hollowed out. Another technique used for cloning is called "embryo splitting,"(4) which was used to create Tetra, a monkey.

First, an egg from the mother and a sperm from the father are taken and used to create a fertilized egg. When the embryo grows into eight cells, the researchers split them into four groups of embryos, each with only two cells each. Each embryo is then implanted into surrogate mothers, which would then create four genetically identical embryos (4).

Although Dolly and Tetra are indeed pioneers for living clones, scientists have decided to tinker in exotic pastures that don't include sheep, cattle, or monkeys. Seeing that their experiments with these animals have not resulted in utter failure, their hopes are high for restoring endangered species to their regular habitat though cloning. The most recent experiment was Noah (7), an Asian ox, or gaur, that was implanted into Bessie as an embryo.

With high expectations (9) for a gaur to be a transgenic birth, the ACT project injected 36 cows with embryos of gaurs, with only four resulting in embryonic growth past the mid-term. Three other cows also had positive results, but their embryos were removed for scientific testing. Irony has it, then, that the birth was successful and Noah was born as healthy as the ox he was, but died two days after his birth (8). The death was associated to an ordinary case of dysentery (10), so researchers are excited that they could prove the possibilities of cloning an endangered, and hopefully in the future even an extinct, animal through transgenic cloning.

ACT also had a press release on background information on the bucardo, a Spanish mountain goat. It said (11):

"The bucardo mountain goat (Capra pyrenaica pyrenaica) had been listed as an endangered species and protected under Spanish law since 1973. Poaching and habitat destruction, however, had not ceased and natural disasters like landslides continued to plague the animal. In January 2000, the last surviving Bucardo mountain goat was found killed by a falling tree and the animal became extinct.


"When it became apparent in the spring of 2000 that conservation efforts were not going to be successful, biologists chose another route to protect the species and took a tissue sample from the 13 year-old Bucardo female only months before her death for possible future use in cloning technologies."

Although no attempts have been made as of yet to begin cloning this specific extinct species, scientists trust this has a higher rate of success than something cloning a mammoth (12), whose frozen cells have been damaged to a point that restructuring them would be nearly impossible. However, in Australia, talk of cloning a Tasmanian tiger (13) has caught our attention.

The Tasmanian tiger, or thylacine, has been extinct for nearly 70 years, although preserved pups have been kept in storage for exactly this purpose. With the appearance of Dolly, Australian scientists concluded that science was advanced to the point that cloning the extinct animal was not a dream but a tangible possibility. By extracting tissue samples of the pup, they will be able to reconstruct the DNA and thus use the process of ACT to clone the thylacine. Since thylacines are not really tigers, but marsupial wolf-like creatures, the mother would most likely be an animal most similar to it like the Tasmanian devil or any other marsupial.

Arguments that ensue say that scientists want to play God, although sightings of thylacines occasionally surface (13). The question that remains is if cloning extinct or endangered animals is really the way to go around nature's own choice of evolution, or if it would simply dispute Darwin's theory of 'Survival of the Fittest' and make it a moot point in science, so people could continue hunting and impinging on the environment of endangered animals and simply clone them if they are highly endangered. However, would these clones be evolved forms, or would they be able to evolve and change to become adapted to their environment, or would they simply be hunted down again or live in zoos because they have no more environment to live in? Scientists that tinker with fate are not yet discussing these moral questions, but as soon as an extinct animal is actually brought to life, such questions are likely to become a much larger issue.

1)The 6th Day

2)Let's Go to the DNA Zoo!

3)Advanced Cell Technology

4)Researchers clone monkey by splitting embryo

5)A Clone in Sheep's Clothing


7)Scientists close to first successful cloning of extinct animal

8)Rare Cloned Ox Dies

9)Scientists Close on Extinct Cloning

10)Cloned baby gaur dies


12)Cloning Is No Extinction Panacea

13)Bringing Back the Tiger

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