Now what? Cloned Pig! all in the name of ‘health’
Cloning May Lead to Healthy Pork
By GINA KOLATA
March 27, 2006
A group of university researchers said yesterday that they had
created what sounds like a nutritional holy grail: cloned pigs that
make their own omega-3 fatty acids, potentially leading to bacon and
pork chops that might help your heart.
For now, the benefits of the research are theoretical. Omega-3 fatty
acids, which have been linked to a lowered incidence of heart
disease, are primarily found in fish. No one knows whether they would
have the same effect if eaten in pork.
And government approval for such genetically modified foods is
certain to face monumental opposition from some consumer groups. Some
already object to feeding farm animals genetically modified grain,
and genetically modifying the animals themselves and cloning them
would be “a double whammy,” said Joseph Mendelson, the legal director
for the Center for Food Safety, a nonprofit group that opposes the
use of genetically engineered products. “I am confident that
consumers would not want them.”
Still, some scientists say the findings, published online by the
journal Nature Biotechnology, are an important forerunner of things
to come. Although close to a dozen animals have been cloned in the
decade since Dolly the sheep, using cloning to change the nutritional
value of farm animals is groundbreaking.
“At this point, it’s a new era,” said Alice H. Lichtenstein, a
professor of nutrition science and policy at the Gerald J. and
Dorothy R. Friedman School of Nutrition Science and Policy at Tufts
University.
Alexander Leaf, an emeritus professor of clinical medicine at
Harvard, said he was confident that pork and other foods with
omega-3’s would eventually get to American consumers and that they
would be better for it.
“People can continue to eat their junk food,” Dr. Leaf said. “You
won’t have to change your diet, but you will be getting what you
need.”
For years, people have been urged to eat fish rich in omega-3 fatty
acids. But fish can be expensive, not everyone likes it, and
omega-3’s are in greatest abundance in oily fish like tuna, which
contains mercury.
That nutritional conundrum led a group of scientists from Harvard
Medical School, the University of Missouri and the University of
Pittsburgh Medical Center to think of modifying pigs.
What resulted was five white piglets with muscle tissue larded with
omega-3 fatty acids. They live at the University of Missouri in
individual pens with fiberglass-railed sides, concrete floors and
black foam pads for beds.
Pigs with their own omega-3 fatty acids exist in nature, notably a
Spanish breed called Ibérico. But Dr. Jing X. Kang, an associate
professor of medicine at Harvard Medical School and the lead author
of the new paper, said pigs were only the beginning, adding that he
was also developing cows that made omega-3’s in their milk and
chickens that had the fatty acids in their eggs.
It will be years before such products make their way to market, if
ever. Michael Herndon, a spokesman for the Food and Drug
Administration, said in an e-mail message that research with
genetically engineered animals would probably require approval from
the agency and that the F.D.A. “also expects documentation of plans
regarding the disposition of all investigational animals after their
participation in the study is completed.”
Mr. Herndon said the F.D.A. had not yet approved any genetically
modified animals for food.
Mr. Mendelson of the Center for Food Safety added that his group
worried about the ability of the food and drug agency to determine
the safety of genetically modified foods. And he said the cloning
process could produce unhealthy animals.
For those who do not object to genetically modified or cloned
animals, the question is whether eating such altered foods will make
a difference in health. And on that, “all bets are off,” said Dr.
Lichtenstein of Tufts.
Many questions remain, she said: How important are omega-3 fatty
acids to human health? Would getting the fatty acids in meat be the
same as getting them in fish? And is it really such a good idea to
put omega-3’s into foods like pork that contain saturated fats and
cholesterol, which could increase risk of heart disease?
Dr. Kang said the work began a few years ago when he put a gene for
the production of omega-3 fatty acids into mice. Mammals do not have
that gene; it is found instead in microorganisms, plankton, algae and
worms, he said. Fish get the fatty acids by eating algae.
Dr. Kang used a gene from roundworms that converts an abundant form
of fatty acid, omega-6, to omega-3. He had to modify the worm enzyme,
making it into one that would function in mammals.
Then he injected the gene for the enzyme into mouse embryos, some of
which took it up, yielding mice that made their own omega-3’s. (In a
paper that is being readied for publication, he says these mice are
protected from a variety of chronic illnesses, presumably because
they make the fatty acids.)
The next step was to create pigs with the enzyme. That work was done
by Randall S. Prather, a pig cloning expert at the University of
Missouri, who used genetically modified pig cells to create the five
cloned pigs that had the gene in every cell of their bodies and made
their own omega-3 fatty acids in their muscles.
Although pigs have been cloned before — along with a growing list of
animals, including sheep, mice, rats, cows, goats, rabbits, cats, a
mule, a horse and a dog — these are the first livestock to be cloned
and genetically modified to make omega-3’s.
Dr. Prather said the omega-3 pigs, born in November, will be bred
when they reach puberty. Then, he said, “we will distribute them to
researchers who are interested.”
Pigs are often used to study heart disease, and the cloned pigs offer
a new opportunity, Dr. Prather said. Instead of comparing human
populations who happen to eat, or not eat, foods with abundant
omega-3, scientists can ask their question directly: Compared with
pigs without the omega-3 fatty acids, do these cloned pigs have a
reduced heart attack risk, or don’t they?
Topics: Misc., Ranting & Rambling |