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We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More. Therefore, unlike Rainbow, CC developed without any cells that specified orange coat color. The result is CC's black and white tiger-tabby coat. Rainbow and CC are living proof that a clone will not look exactly like the donor of its genetic material. Programs are underway to clone agricultural animals, such as cattle and pigs, that are efficient producers of high-quality milk or meat. A group of researchers at Utah State University led by Dr.
Their aim isn't to produce animals for consumption—cloning is far more labor-intensive and expensive than conventional breeding methods. Instead, they want to use these animals as breeding stock. The important thing to know about beef cattle is that the quality and yield of their meat can be assessed only after they are slaughtered. And male animals are routinely neutered when they're a few days old. That is, their testes are removed, so they are unable to make sperm. But cells from a high-quality carcass can be cloned, giving rise to an animal that is able, though conventional breeding methods, to pass its superior genes to its offspring.
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. The graft is then rejected by the body's defense mechanisms and destroyed, just as if it were a disease-causing organism.
Genetic modification can be used to disguise an animal's cells and organs and thereby reduce or even eliminate rejection of the graft. Thousands of people die every year because of the unavailability of human organs for transplantation.
Genetically modified animal organs could begin to fill this need. For example, Parkinson's, Alzheimer's and Huntington's diseases are caused by the death of specific cells in the brain. Preliminary research has shown that it is possible to alleviate the symptoms of Parkinson's disease by transplanting fetal pig brain cells into a patient's brains.
A related technique may be applied to diabetes, another widespread disorder. Currently diabetics rely on insulin therapy, which is far from being an ideal treatment and is certainly not a cure.
The transplantation of genetically modified animal pancreatic islet cells--which could secrete insulin in response to the body's varying glucose levels, just as the cells in a healthy individual do--could effectively cure the disease. There are numerous other examples, so transplantation therapy could potentially relieve suffering in many thousands or even millions of patients.
Recently, researchers have demonstrated how to make such proteins in the milk of genetically modified animals. The mammary gland is a magnificent protein-manufacturing organ, and it also provides a convenient delivery system. For example, if you developed kidney disease and needed a new kidney. A family member might be a close enough match that they could donate a kidney or you might get lucky and find an organ donor elsewhere.
However, there is a chance that your body could reject the organ. Anti-rejection medication drugs can lower that chance, but they will also lower your immune system. Stem cells have the ability to solve the organ rejection problem. Because stem cells can turn into any type of cell, they can be used to create the organs or tissue that you need, using your own cells.
Since the cells are your own, your body would be less likely to attack them like as if they were foreign cells. While stem cells hold a lot of potential, the difficulty in getting the cells remains.
Stems cells are the most bountiful in embryos. These cells can also be harvested from umbilical cords as well as some tissues in the adult body. Adult stem cells are harder to harvest and may have less potential than embryonic stem cells. The challenge then becomes how to create embryonic stem cells for adults. Their work used donated human embryos, removed the egg's DNA, and then replaced it with DNA taken from adult skin cells.
The laboratory then used a combination of chemicals and electrical pulses to get the embryo to grow and develop stem cells. These stem cells could then be used, in theory, to create organs and tissues for the person who donated their skin cell DNA.
While this research is very promising, cloning embryos for stem cells remain highly controversial. Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Healthy ageing of cloned sheep. Nat Commun.
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