Топики по английскому языку

Топики по английскому языку Abstract From Cloning Where Do We

Работа добавлена на сайт bdrip.ru: 2015-04-14

Abstract From: Cloning : Where Do We Draw The Line? Essay, Research Paper

Abstract from: Cloning : Where Do We Draw the Line?

The first attempt in cloning was conducted in 1952 on a group of frogs.

The experiment was a partial success. The frog cells were cloned into other

living frogs however, only one in every thousand developed normally , all of

which were sterile. The rest of the frogs that survived grew to abnormally large

sizes. In 1993, scientist and director of the in vitro lab at George

Washington University, Jerry Hall and associate Robert Stillman, reported the

first ever successful cloning of human embryos. It was the discovery of in-

vitro fertilization in the 1940?s that began the pursuit to ease the suffering

of infertile couples. After years of research, scientists learned that “in a

typical in-vitro procedure, doctors will insert three to five embryos in hopes

that, at most, one or two will implant” (Elmer-Dewitt 38). And that “a woman

with only one embryo has about a 10% to 20% chance of getting pregnant through

in-vitro fertilization. If that embryo could be cloned and turned into three or

four, thechances of a successful pregnancy would increase significantly”(Elmer-

Dewitt 38).

The experiment the scientists performed is the equivalent of a mother

producing twins. The process has been practiced and almost perfected in

livestock for the past ten years, and some scientists believe that it seems only

logical that it would be the next step in in-vitro fertilization. The procedure

was remarkably simple. Hall and Stillman “selected embryos that were abnormal

because they came from eggs that had been fertilized by more than one sperm”

(Elmer-Dewitt 38), because the embryos were defective, it would have been

impossible for the scientist to actually clone another person. They did however,

split the embryos into separate cells, as a result creating separate and

identical clones. They began experimenting on seventeen of the defective

embryos and “when one of those single-celled embryos divided into two cell?the

scientists quickly separated the cells, creating two different embryos with the

same genetic information” (Elmer-Dewitt 38). The cells are coated with a

protective covering “called a zona pellucida, that is essential to development”

(Elmer-Dewitt 38), which was stripped away and replaced with a gel-like

substance made from seaweed that Hall had been experimenting with. The

scientists were able to produce forty-eight clones, all of which died within six

days. Other scientist have been quoted saying that although the experiment is

fairly uncomplicated, it had not been tested before because of the moral and

ethical issues surrounding an experiment such as this one. Some people believe

that aiding infertile couples is the only true benefit to cloning human embryos,

and fear that if the research is continued it could get out of hand. Other

advantages that have been suggested include freezing human embryos for later use,

in the event that a child should get sick or die. If a parent has had their

child?s embryos cloned and frozen and their child dies at an early age of crib

death, the parents could have one of the frozen embryos de-thawed and implanted

into the womb. Nine months later, the mother would give birth to a child that

was identical to the one they had lost. Or if a four year old child develops

leukemia and requires a bone marrow transplant. A couple could implant a pre-

frozen embryos clone of their first child and produce an identical twin as a

guarantee for a perfect match. The parents would therefore have identical twins

that were four years apart. The disadvantages are endless. If this type of

technique were exploited and used in vain, we could be heading down “a tunnel of

madness”(Elmer-Dewitt 37). “Researchers have developed DNA- analysis techniques

to screen embryos for?disorders, but the procedures require snipping cells off

embryos, a process that sometimes kills them”( Elmer-Dewitt 39). It is expected

that the idea of throwing away an embryos because it is disease ridden will

throw pro-life activists into a frenzy (Elmer-Dewitt 39). It is one thing to

exercise the freedom of chose to abort an unwanted child for whatever reason,

but to throw one a way due to a pre-understanding that it carries a disease, in

my opinion, is unethical. These types of possibilities are producing moral and

ethical debates among ethicists the world over. Most countries have set

regulations concerning cloning human embryos and in some countries it is an

offense punishable by law and requires incarceration . Between the medical

contributions and the ethical questions surrounding cloning human embryos, it is

unlikely that we will have the opportunity to discover if further research to

Hall and Stillman?s experiment could actually produce human beings.


Elmer-Dewitt, Philip. “Cloning: Where Do We Draw the Line?” Time Magazine.

November 8th, 1993: 37-42.

Колонка Info

gellon.ru - Рефераты

По всем вопросам - пишите письма)

Контактные данные находятся в разделе: "Контакты"

Присылайте Ваши рефераты для публикаций

Работы размещены на сайте в целях ознакомления и не преследуют коммерческих целей