Tag: Cloning

Researchers Demonstrate Therapeutic Cloning in Cows

Researchers at Advanced Cell Technology and Children’s Hospital in Boston this week announced they had for the first time managed to use therapeutic cloning to produce working tissues that were successfully implanted in cows.

In the experiment, researchers used cells from an adult cow to create a cloned embryos. The embryos was then implanted in a host cow where it grew for several weeks before researchers harvested stem cells from the cloned embryos (this is a step that would be unnecessary in human beings, since human stem cells can be grown in the lab, while no one has yet figured out how to grow cow stem cells in the lab).

The stem cells were then placed on scaffolds in a laboratory which caused them to grow into a few dozen miniature kidneys and patches of heart tissues. The miniature kidneys and heart tissue were then transplanted back into the cows that the adult cells were taken from.

The result was that the implants were not rejected by the cows’ immune system, since the implants were genetically identical to the cows’ existing tissues, and the tissues and organ functioned properly. The heart tissue grew onto the heart, and the miniature kidneys functioned properly including producing a urine-like fluid.

“This study is proof of principle that therapeutic cloning can be used to create tissues without any threat of reaction,” Dr. Anthony Atala of Children’s Hospital told The Boston Globe.

“These results bode well for the future of human therapeutic cloning,” Robert Lanza of Advanced Cell Technology told The Scotsman. “Cloning could theoretically provide a limitless supply of cells and organs for any type of regenerative therapy.

Sources:

Researchers implant cloned cow tissues. Raja Mishra, Boston Globe, June 3, 2002.

Cloned embryo success for US scientists. Tara Womersley, The Scotsman, June 3, 2002.

Researchers say therapeutic cloning experiments show promise in cows. Paul Elias, Associated Press, June 2, 2002.

U.S. Researchers Clone Calf From Cells of Dead Cow

Researchers at the University of Georgia announced this week that they had successfully cloned a calf from the cells of a cow that had been dead for 48 hours before her genetic material was extracted.

This is the first time a cow has been cloned from cells of a dead animals. European researchers last year announced they had cloned a sheep from cells taken from an animal that had been dead 18 to 24 hours.

The researchers claim that this will allow cattle producers to select the best beef stock from their herds to clone (since it is impossible to judge how suitable a given cow is for meat until after it has been killed).

Further down the road, this technique could allow for the cloning of cows from meat that is tested for low susceptibility to diseases such as Mad Cow.

Source:

Scientists Clone Calf from Dead Cow. Erin McClam, Associated Press, April 25, 2002.

U.S. Researchers Clone Rare Pig

Wisconsin-based company Infigen announced recently that it had successfully produced clones of a rare pig. More importantly, it claims to have developed advances in cloning that allow it to produce clones with just one round of embryo implantations rather than the several rounds that have been required up until now.

The pig was the last female in one of four remaining bloodlines of Gloucestershire Old Spots in North America. Robyn Metcalfe, founder of the Kelmscott Rare Breeds Foundation in Maine, had unsuccessful tried to get the animal to reproduce via natural breeding and artificial insemination.

Infigen offered its services for free to prove its technology. Pigs have been cloned perviously, but typically two or three pigs are implanted with hundreds of embryos in order to achieve a single successful pregnancy.

Infigen has been able to eliminate the need for implanting multiple animals. In February it released results showing that it had produced three successful pregnancies from three implantations in pigs, and in this case managed to produce a successful pregnancy from a single implantation.

As cloning researcher Randall Prather told NewScientist.Com, “Sounds like they got it working pretty well.”

Source:

Rare pig cloned in single cycle. Sylvia Pagan Westphal, NewScientist.Com, April 23, 2002.

Rare pig breed cloned. The BBC, April 24, 2002.

French Researchers Clone Rabbits

Researchers in France recently announced they had successfully cloned rabbits. Their report, published in the Nature Biotechnology, describes how the researchers used cells from an adult rabbit to produce several cloned rabbits.

Like other cloned animals, this procedure required hundreds of cloned embryos to produce six live births. Two of the rabbits died shortly after birth, leaving four clones that appear to be growing and reproducing normally.

Rabbits are an important research tool because they are genetically more similar to human beings than are other lab animals, such as mice, but they have a much shorter gestation period than larger mammals such as sheep or cows.

“The advantage is that rabbits reproduce so quickly,” Dr. Jean-Paul Renard told The BBC. “The pregnancy lasts one month, then it takes four months to sexual maturity…” The average gestation period for a rabbit is only 31 days, producing an average litter size of 8.

Combined with the cloning technique, this would allow researchers to create genetically modified rabbits for medical research purposes very quickly.

For example, one of the areas that the French researchers are already working on is creating a rabbit model for cystic fibrosis. Cystic fibrosis is caused by a defect on a gene that happens to be very similar between human beings and rabbits. The ability to produce a large number of rabbits with a similar defect on this gene could lead to a much better animal model for cystic fibrosis and improved progress on understanding and treating the disease.

Rabbits are also used in heart disease as well as the production of monoclonal antibodies (which animal rights activists like to pretend are non-animal alternatives to research). The rabbit’s immune system is similar to human beings, and studies of how rabbits cope with organ transplants has yielded important information on preventing organ transplant rejection in human beings.

In fact, as The Washington Post noted, cloning technology itself rests in part upon advances in the understanding of reproduction obtained through extensive research in rabbits.

Sources:

Rabbits join the cloning club. The BBC, March 29, 2002.

A big hop forward: Rabbits cloned; Research promise seen in second lab animal to be replicated. David Brown, Washington Post, March 30, 2002.

These Easter bunnies are clones. Roger Highfield, Daily Telegraph (London), March 30, 2002.

Genetically Modified Dairy Cows Cloned in Australia

Australia joined the United States, Europe, and New Zealand in producing its first cloned and genetically modified dairy calves.

A team of researchers at the Monash Institute of Reproduction and Development first cloned several cow embryos. They then inserted an extra bovine protein gene taken from a cow cell into the embryos. The extra gene boosts the amount of protein in milk expressed by the cows, though it will be awhile before researchers learn by how much the protein content is increased.

The same technique, of course, could be utilized to make the cows express other compounds, such as pharmaceuticals, in milk. “Being able to add specific genes to cloned calves will provide us with the potential to produce milk containing human vaccines and medicines for diseases such as hemophilia,” said Monash Institute director Alan Trounson.

Such possibilities are still 5-10 years away, however.

Source:

Australia breeds super milkers. AAP, March 27, 2002.

Australia look to milk cow cloning. Reuters, March 27, 2002.

Protein shakes on the way after cloned cows born. Penny Fannin, Sydney Morning Herald, March 28, 2002.

Cloning Cats

Researchers at Texas A & M were in the news this week when word leaked that they managed to successfully clone a cat. A number of research efforts are underway to clone cats and dogs, but this was the first such success.

Much of the media coverage focused on the possibility of cloning pets. The Canadian Press quoted Texas A & M researcher Duane Kraemer as claiming that some people have already stored cells from their departed pets in the hope that cloning might one day bring back copies of said pets.

A more important possibility is the role that cloned cats may play in medical research. This possibility brought condemnation from the Humane Society of the United States‘ Wayne Pacelle who described the announcement as “unfortunate news” and told the Canadian Press that researchers should move away from using animals in medical research.

But research in cats has provided important information about a variety of issues related to human physiology, especially about vision. The way cats process vision is very similar to the processes in human beings. In fact, David Hubel and Torsten Wiesel won the 1981 Nobel Prize for Physiology or Medicine for their research in cats and monkeys that completely revolutionized understanding of how vision is processed.

Pacelle and animal rights activists are free to maintain that advances in human knowledge thanks to animal research are “unfortunate,” but they will have to excuse the rest of us for finding this to be incredibly exciting news.

Source:

Texas researchers announce successful cloning of a cat; dogs are next. Malcolm Ritter, Canadian Press, February 15, 2002.

More than nine lives for this cat. Antonio Regalado, The Wall Street Journal, February 14, 2002.