Реферат по предмету "Иностранный язык"


Cloning Essay Research Paper CLONINGIntroduction What is

Cloning Essay, Research Paper

CLONING

Introduction: What is Cloning?

Cloning is the production of an exact genetic duplicate of a living organism.

Clones are created from an unfertilised egg and a donor cell.

Two different procedures have been referred to as “cloning”:

? Embryo cloning involves removing one or more cells from an embryo and encouraging the cell to develop into a separate embryo with the same DNA as the original.

? Adult DNA cloning involves removing the DNA from an embryo and replacing it with the DNA from another person. The embryo develops into a new human with the same DNA than its donor.

I-Arguments for cloning

A- Cloning of animals:

? Scientists are trying to create transgenic pigs, which have human genes. Their heart, liver or kidneys could be used as organ transplants in humans. This would save many lives. Transgenic animals could be cloned to produce as many organs as are needed.

? Researchers have produced transgenic animals. These are genetically altered, in order to produce human hormones or proteins that can be used to heal humans. Cloning would produce as many genetically altered animals as are needed.

B- Human adult DNA and Embryo cloning;

? Treatments for damage to the brain or the nervous system might be possible due to cloning. Damaged nerve tissue in adults does not regenerate. However, stem cells might be capable of repairing the tissue. Because of the large number of stem cells required, human embryo cloning would be required.

? Parents who are known to be at risk of giving a genetic defect to a child could use of cloning. A fertilized ovum could be cloned, and the duplicate tested for the disease or disorder. The clone would be free of genetic defects.

? Cloning could produce a reservoir of “spare organs”. Fertilized ova could be cloned into multiple zygotes; one could be implanted in the woman and allowed to develop into a normal baby; the other zygotes could be frozen for future use. In the event that the child required a bone marrow transplant, one of the zygotes could be taken out of storage, implanted, allowed to mature to a baby and then contribute some of its spare bone marrow to its (earlier) identical twin. Bone marrow can be harvested from a person without injuring them.

? A heterosexual couple in which the husband was completely sterile could use adult DNA cloning to produce a child. An ovum from the woman would be coupled with a cell from the man’s body. Both would contribute to the child. They might find this more satisfactory than using the sperm of another man.

? Two lesbians could elect to have a child by adult DNA cloning rather than by artificial insemination by a man’s sperm. Each would then contribute part of her body to the fertilized ovum: one woman would donate the ovum, the other woman the genetic material. Both would be genetically involved in the conception. They might find this more satisfactory than in-vitro fertilization with a man’s sperm.

II-Arguments against cloning

? A genetic test could also be used to eliminate zygotes of a particular gender, without requiring a later abortion. In the same way, when the gene or genes that determine sexual orientation are located, cloning could also be used to eliminate zygotes of a particular sexual orientation.

This is not natural and considered by many people to be unethical. Should people really be

allowed to decide or influence whether their child will be homosexual or a particular gender?

? Cells seem to have a defined life span built into them. “Dolly” was created from a cell that was about 6 years old; this is middle age for an ewe. It appears that Dolly’s cells are also middle-aged. She was about 6 years old when she was born. She is expected to live only for 5 years. If this is also true for humans, then cloned people would have a reduced life expectancy.

? There is no guarantee that the first cloned humans will be normal. They might suffer from some disorder that is not detectable by ultrasound. They may be born disabled.

? A country might finance a program similar to that of Nazi Germany whereby humans were bred to maximize certain characteristics. Once the “perfect human” was developed, embryo cloning could be used to replicate that individual and produce unlimited numbers of clones. The same technique could be used to create a genetic underclass for exploitation: individuals with sub-normal intelligence and above normal strength.

? Some people have expressed concern about the effects that cloning would have on relationships. For example, a child born from an adult DNA cloning from his father would be, in effect, a delayed twin of one of his father. That has never happened before and may lead to emotional difficulties.

There are many advantages to cloning in it could be used positively in many areas such as infertility and treatment for damage to the brain. But cloning could also lead to all forms of Eugenism (I.e: race, gender, sexual orientation…) Should humans be allowed to play god? The Ethics of people “choosing” their offspring is highly questionable.




Не сдавайте скачаную работу преподавателю!
Данный реферат Вы можете использовать для подготовки курсовых проектов.

Поделись с друзьями, за репост + 100 мильонов к студенческой карме :

Пишем реферат самостоятельно:
! Как писать рефераты
Практические рекомендации по написанию студенческих рефератов.
! План реферата Краткий список разделов, отражающий структура и порядок работы над будующим рефератом.
! Введение реферата Вводная часть работы, в которой отражается цель и обозначается список задач.
! Заключение реферата В заключении подводятся итоги, описывается была ли достигнута поставленная цель, каковы результаты.
! Оформление рефератов Методические рекомендации по грамотному оформлению работы по ГОСТ.

Читайте также:
Виды рефератов Какими бывают рефераты по своему назначению и структуре.