Cloning is a technique to produce the genetic twin of another organism,
but it can also be used for other purposes. There are three main types of
cloning technologies.
1. Recombinant DNA technology or DNA cloning,
2. Reproductive cloning and
3. Therapeutic cloning.
DNA cloning refers to a process where a DNA fragment of
interest is transferred from one organism to a self � replicating genetic
element such as a bacterial plasmid. The DNA of interest can then be
propagated in a foreign host cell. This technology has been around since
the 1970�s, and it has become a common practice in molecular biology
laboratories today. This technology is important for learning about other
related technologies, such as gene therapy, genetic engineering of
organisms, and sequencing genomes. Gene therapy can be used to treat
certain genetic conditions by introducing virus vectors that carry
corrected copies of faulty genes into the cells of a host organism. Genes
from different organisms that improve taste and nutritional value or
provide resistance to particular types of disease can be used to
genetically engineer food crops.
Reproductive cloning is a technology used to generate
an animal that has the same nuclear DNA as another currently or previously
existing animal. Dolly was created by this technology. If the low success
rates can be improved (Dolly was only one success out of 276 tries),
reproductive cloning can be used to develop efficient ways to reliably
reproduce animals with special qualities. For example, drug producing
animals or animals that have been genetically altered to serve as models
for studying human disease could be mass-produced. Reproductive cloning
also could be used to repopulate endangered animals or animals that are
difficult to breed. Cloning extinct animals presents a much greater
challenge to scientists because the egg and the surrogate needed to create
the cloned embryo would be of a species different from the clone.
Therapeutic cloning, also called "embryo cloning" is
the productive of human embryos for use in research The goal of this
process is not to create cloned human beings, but rather to harvest stem
cells that can be used to study human development and to treat disease.
Stem cells are important to biomedical researchers because they can be
used to generate virtually any type of specialized cell in the human body.
Many researchers hope that one day stem cells can be used to serve as
replacement cells to treat heart disease, Alzheimer�s, cancer, and other
diseases. Therapeutic cloning technology may some day be used in humans to
produce whole organs from single cells. Much work still needs to be done
before therapeutic cloning can become a realistic option for the treatment
of disorders. Another potential application of cloning to organ
transplants is the creation of genetically modified pigs from which organs
suitable for human transplant could be harvested.
Should humans be cloned? Physicians from the American
Medical Association and scientists with the American Association for the
Advancement of Science have issued formal public statement, advising
against human reproductive cloning. Due to the inefficiency of animal
cloning and the lack of understanding about reproductive cloning, many
scientists and physicians strongly believe that it would be unethical to
attempt to clone humans. Scientists do not know how cloning could impact
mental development. While factors such as intellect and mood may not be as
important for a cow or a mouse, they are crucial for the development of
healthy humans. With so many unknowns concerning reproductive cloning, the
attempt to clone humans at this time is considered potentially dangerous
and ethically irresponsible.
Several attempts and trials have been made to produce
improved quality of animals. Similar experiments are also underway to
improve the level of human beings. Scientists aim at producing individuals
having desired qualities. The attempts to improve the cell quality in
animals and humans by changes in genes have not yielded the desired
results. Attention of scientist has now shifted from genes to electro
magnetic fields for improving the quality of cell. Experiments by several
researchers have shown that these methods are successful to some extent in
improving the body structure but fail to produce the desired qualities.
The scientific attempts can not assure that the moral, intellectual and
social qualities will improve. Such conclusions were drawn by yogis in the
past. They had ruled that the only way to improve the quality of the
offspring is that both the parents should prepare themselves by spiritual
practices before they decide to have a child.
Yogic practices like penance and meditation reform the
chromosomes which improve the quality of the offspring. This is the only
way to improve the moral, intellectual and social qualities in the
offspring.
