Реферат на тему Abstract From Cloning Where Do We
Работа добавлена на сайт bukvasha.net: 2015-06-05Поможем написать учебную работу
Если у вас возникли сложности с курсовой, контрольной, дипломной, рефератом, отчетом по практике, научно-исследовательской и любой другой работой - мы готовы помочь.
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.
References
Elmer-Dewitt, Philip. “Cloning: Where Do We Draw the Line?” Time Magazine.
November 8th, 1993: 37-42.