What is Cloning?
Cloning Occurs Naturally?
Artificial Cloning
How are Genes Cloned?
How are Animals Cloned?
Do Cloned Animals look Identical?
Potential Use of Cloned Animals?
Drawbacks
What is cloning?
A process that can produce genetically identical copied material, which has the same genetic
makeup as the original.
Cloning Occurs Naturally:
In humans and other mammals are known as twins. These twins are produced when a fertilized
egg splits, creating two or more embryos that carry almost identical DNA.
In plants and single-celled organisms (i.e. bacteria) produce genetically identical offspring
through a process called asexual reproduction. Asexual reproduction means that a new
individual is generated from a copy of a single cell from the parent organism.
Artificial Cloning:
There are three different types of cloning: gene, reproductive and therapeutic cloning. Gene
cloning produces copies of segments of DNA. Reproductive cloning produces copies of whole
animals. Therapeutic cloning produces embryonic stem cells for experiments aimed at creating
tissues to replace injured or diseased tissues.
Gene cloning has a very different method from reproductive and therapeutic cloning.
Therapeutic and reproductive cloning are quite similar in their methods but have different
purposes.
How are genes cloned?
Researchers insert a gene from one organism, aka “foreign DNA”, into the genetic material of a
carrier called a vector. After the gene is inserted, the vector is placed under controlled
environments and made to multiply. This results in the gene being copied over and over again.
How are animals cloned?
The technique used is called reproductive cloning. In this kind of cloning, researchers remove a
mature somatic cell from the animal of choice. Then they transfer the DNA of the donor
animal’s somatic cell into an oocyte that had its own nucleus removed.
There is two ways to add the DNA from the somatic cell into the oocyte. They can (1) remove
the DNA-containing nucleus of the somatic cell and inject it directly into the empty egg. Or (2)
they can use an electrical current to fuse the entire somatic cell with the empty egg.
After the egg and DNA from the somatic cell are fused, the egg is allowed to develop into an
early-stage embryo in the test-tube and then is implanted into the womb of the adult animal.
Eventually that animal would give birth and that animal would have the same DNA as the
somatic cell of the donated animal.
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Do cloned animals look identical?
No, they don’t always look identical because the environment plays a big role of how the clone
turns out.
Potential use of Cloned animals?
Genetic modification to benefit us in fields of medicine and agriculture. For example, some
researchers have been able to clone sheep that have been genetically modified to produce milk
that contains human protein essential for blood clotting. Also drug testing on animals that are
genetically identical instead of genetically diverse is beneficial because their responses to the
drugs should be uniform.
Furthermore, cloning could bring back up the populations of endangered species. The only
controversy is that the animals would be all the same and may lack the genetic variability
necessary for species to survive.
Some people have also thought of cloning their diseased pet in hopes of having a similar one
replace the dead one.
Drawbacks:
One of the disadvantages is that technology is still uncertain. Even though scientists were
successful in cloning Dolly the sheep, they had to do many other test runs to finally get a clone.
Dolly also died of a disease not seen in sheep so young, many other of the cloned animals also
have turned out with really strange deformities.
Losing gene diversity is another disadvantage. By having clones, genetic diversity seizes to exist.
Genetic diversity is what keeps a population from being whipped out by a disease. So with
everyone’s genetic DNA being the same, it could lead to extinction.
Another disadvantage of cloning is that there are a lot of ethical considerations that people
would protest against. People are already protesting that scientists are trying to “play God”
because they are specifically modifying animals and/or humans to come out the way they want
them to instead of by chance. Also the treatment of clones is a debate, mostly because people
want to know that the clones are still treated fairly and humanely and not just as an
experiment.
Last but not least, another drawback is the risk of technology being abused. If cloning turns out
to be really successful in the future, it would have to be closely monitored so that it “doesn’t
fall into the wrong hands”. There will always be someone that is looking to use cloning for their
personal use, and many feel that the best way to prevent this is by not cloning at all.