Scientists have also cloned mules, a reproductively sterile hybrid of a male donkey and a female horse; dairy cows; and horses. One gelded racing horse, a male whose testes have been removed, has a clone that is available for breeding. Some of the cloned cows produce about twice as much milk as the average producer.
And a cloned racing mule is ranked among the best in the world. Farm animals such as cows, sheep, and goats are being genetically engineered to produce drugs or proteins that are useful in medicine. As an example, scientists could take cells from a cow that produces large amounts of milk and grow them in culture. Then they could insert a gene into the DNA of these cells that codes for a drug or a vaccine. If they take the nucleus from one of these cells and transfer it to a cow egg, it could develop into a cow that makes the drug in its milk.
Since every cell in the cow would carry the drug gene, it could pass the gene to its offspring, creating a whole herd of drug-producing cows. Even better, we could avoid the issue of the genetic reshuffling that happensduring sexual reproduction and simply clone our drug-producing cow.
The prospect of cloning humans is highly controversial, and it raises a number of ethical, legal, and social challenges that need to be considered. The vast majority of scientists and lawmakers view human reproductive cloning—cloning for the purpose of making a human baby—immoral. Supporters see it as a possible solution to infertility problems. Some even imagine making clones of geniuses, whose work could advance society.
Far-fetched views describe farms filled with clones whose organs are harvested for transplantation—a truly horrific idea. For now, risks and technical challenges—as well as laws that make it illegal—will probably keep human reproductive cloning from becoming a reality. Even though many species have been cloned successfully, the process is still technically difficult and inefficient. The success rate in cloning is quite low: most embryos fail to develop, and many pregnancies end in miscarriage.
Current efforts at human cloning are focused on creating embryonic stem cells for research and medicine, as described above. However, many feel that this type of therapeutic cloning comes dangerously close to human reproductive cloning. And once techniques become more streamlined and efficient, they fear that some may be tempted to take that next step.
From a technical and moral standpoint, before human cloning becomes routine, we need to have a good idea of the risks involved. Home Cloning Why Clone? Why Clone? Cloning in Medicine. Cloning animal models of disease Much of what researchers learn about human disease comes from studying animal models such as mice.
Cloning to make stem cells Stem cells build, maintain, and repair the body throughout our lives. Find out more about Stem Cells. Reviving Endangered or Extinct Species. If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media. Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website.
You cannot download interactives. But the first formal genetic study was undertaken by a monk named Gregor Mendel in the middle of the 19th Century. Mendel bred peas and noticed he could cross-pollinate them in certain ways to get green or yellow seeds.
Today, the field of genetics is breaking new ground searching for new ways to treat disease or develop crops more resistant to insects or drought. Empower your students to learn about genetics with this collection of resources. Biotechnology is the use of living systems and organisms to create new technologies. On the simpler end of the spectrum, baking bread with yeast is an example of this interdisciplinary science.
On the more complex side, genetic engineering, biochemistry, and molecular biology are pushing boundaries in an effort to treat illnesses, develop new biofuels, and grow plants more efficiently to feed more people. Use these resources to dig into biotechnology with your students. Even the most basic parts of a cell can enable complex cellular processes, and multifunctional organelles expand these capabilities to make advanced activities possible for higher life-forms.
Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Photograph by Handout. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Scientists test new medicines on cells taken from the embryos before trying the medicines on animals and real people. Tel: Email: info centreofthecell.
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It is mandatory to procure user consent prior to running these cookies on your website. Book Contact us. Scientists around the world continue to argue the advantages of cloning in hopes of being able to research it more thoroughly, but more than 30 countries have already issued bans on human reproductive cloning.
However, the countries of China, Sweden, England, Israel and Singapore do allow cloning for reasons that have nothing to do with human reproduction. Some of the pros of cloning include recreating livestock, deceased pets and bringing extinct species back to life, but arguments against cloning mostly focus on human cloning for reproductive purposes.
Benefits of cloning include being able to create tissue and organs that doctors can use when needed for surgery on the original. If labs can clone and grow only the parts needed, this would eliminate the moral and ethical issues associated with cloning an entire person.
Other benefits include growing stem cells, cloning lab mice genetically engineered for the specific study, bringing back extinct species, reproducing a pet that died and cloning livestock for food.
One of the main drawbacks of cloning is that if the original organism has genetic defects, these transfer to the clone as a copy of the original.
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