POSTED 31 MAY 2007
Dolly's daughters
Remember Dolly, the Scottish sheep who said "Ewe, Two"? Ten years ago, this wooly charmer -- the first mammal clone -- put cloning on the scientific and ethical maps. Produced from the union of a gene-free egg with the bare nucleus of an adult cell, Dolly gamboled across the front pages, attracting notice from the tabloids and just about everybody else.
She history's first identical twin based on an adult mammal.
Ian Wilmut (sitting), father of Dolly the clone,
with James Thomson of University of Wisconsin-Madison, first to clone human
embryonic
stem cells, talking in
Madison, May, 2007, to honor Dolly's 10th birthday.
Photo: Courtesy UW-Foundation.
Long before Dolly's somewhat premature death, embryonic stem cells joined cloning as emblems of a brave new reproductive future.
In bioethics, the epochs date BD and AD: Before Dolly, and After Dolly. Before Dolly, the idea of making a carbon copy of yourself was science fiction or Brave New World. AD, that is theoretically possible (although nobody has yet grown a human clone, as far as we know).
Bio-buzzword
Clone: to make an exact genetic copy -- an identical twin.
After Dolly, society has had to confront the merits of limits on scientific advances. Is more knowledge always a good thing, or are certain scientific pathways best unexplored?
Here's another question: Do clones inspire clowns? In 1998, a Chicago physicist named Richard Seed (of all names!) announced plans to produce the first human clone before disappearing from the headlines. In 2002, a bizarre sect of spaceship-worshipping Raelians claimed that "Baby Eve," the clone, had already been born. She never showed her carbon-copy face.
Dolly the clone, stuffed and displayed at the National
Museums of Scotland. Photo: Trustees
of National Museums Scotland
Dolly's dangers
These scary headlines, even more than the curious crowd who crowed about commencing cloning, raised big questions among scientists, ethicists, and just about everybody else: Even if it proves possible to clone humans for reproduction, is it wise, ethical and safe? Does such cloning amount to playing God?
Beyond reproductive cloning, what about "therapeutic cloning," making a carbon copy of an embryo solely as a source of embryonic stem cells? Because these cells can grow into any body cell, therapeutic cloning might lead to genetically matched spare parts that do not trigger an immune response. But people who believe that life begins at conception condemn research on embryonic stem cells as murder, because the embryo is destroyed when the cells are extracted.
Bio-buzzword
Reproductive cloning: to use cloning to make a new animal.
Ten years AD, cloning discoveries continue to produce surprising scientific results that raise ethical, political and scientific questions. Here are some tidbits we gleaned from a talk by Ian Wilmut, of the Scottish Center for Regenerative Medicine and the Roslin Institute. Wilmut led Dolly's cloning, and remains active in the field.
Researchers
are using reproductive cloning to genetically change pigs so their organs would
escape immune attack after transplant into humans. The idea is to ease the
shortage of transplant organs, and reduce deaths on transplant waiting lists.
In one test, a pig heart transplanted into a baboon lasted 179 days; normally,
the immune system would immediately destroy such a transplant. BTW, Wilmut
says the baboon retained its original-equipment heart, and thus survived the
experiment.
Researchers from the University of Connecticut and the Kagoshima Prefectural Cattle Breeding Development Institute (Japan) examined these cuts of beef (top and middle: produced by cloning; bottom: control animal). All parameters examined were within the normal range of beef products approved for human consumption. Hungry? Photo: Viagen
Cloned animals can be used to create human antibodies. These small, specific molecules are "currently
used for many different human clinical applications; including treatment
of infectious disease, cancer, transplanted organ rejection, autoimmune
diseases and for use as antitoxins," wrote James Robl of Hematech.
This firm is working on genetically educating cows to make human antibodies
(see #1 in the bibliography) in their milk. Cow's mammary glands are good at making proteins, and the idea is to genetically change the animals to make desirable, high-price proteins for medical purposes. "This was a very strong potential use for our technology," says Wilmut. "This could not be done in any other way."
Bucking bulls for rodeo riders are one early beneficiary
of cattle-cloning technology. Trust us, pardner: These gents are as ornery
as rusty ol' barbwire on the Texas range. Photo: Bovance
Meat from cloned cows could soon appear on your dinner plate. The Food and Drug Administration has indicated incipient approval of clone-chops and clone-burgers, and the European Food Safety Authority is probing the safety issue. 
Cloning is already
being used to "breed" better "bucking bulls" for
the rodeo trade.
Jack Hurs was diagnosed with ALS in 1987, and was in stable condition in 2005. Formerly a jogger, he is paralyzed and unable to speak. Photo: ALS Association
Cloning
could be used to study diseases caused by unknown genes. Wilmut points to ALS
(Lou Gehrig's disease), an invariably fatal destroyer of motor nerves. About
10 percent of cases are inherited through mutations that are largely unknown.
The research plan, he says, is to create cell lines with these mysterious
mutations, "and study them any
way you can with modern techniques, to look
for the difference between normal and sick cells. ... The aim is to have
a system where you can test new drugs to find something you can give to
the patient to stop the degeneration. This would be a huge advance."
The Javan banteng is a relative of the cow. Bantengs have been successfully cloned. This could help species preservation, -- although probably less than preserving their habitat. Photo: San Diego Zoo
Cloning could be used to help restore endangered species. In 2003, researchers cloned two Java bantengs, an endangered bovine from Southeast Asia. One of the animals was grossly deformed and put down, but the other is on display at the San Diego Zoo.
Did we forget to mention that a Kentucky fertility-clinic operator told us that he's already implanted five cloned human embryos into women? None became pregnant. Trust us, we'll return to Panos Zavos.
Bio-buzzword
Therapeutic cloning: to use cloning to create stem cells to cure disease. The cells are usually genetically matched to the patient.
Stages of somatic cell nuclear transfer:
A nucleus is removed from one cell and placed in another. Photo:
Roslin Institute
Know-it-all recap
In case you've pulled a Rip Van Winkle for the past 10 years, here's our
50-word cloning recipe.
1. Remove mature cell from the animal you want to clone.
2. Grab an egg from another animal and suck out nucleus and the genes.
3. Squeeze the genes from step 1 into egg from step 2.
4. Zap the cell with electricity, causing it to start dividing.
With luck, that's all there is to it. But cloning mammals is rather inefficient; it took 277 tries to get the single embryo that became Dolly.
Beyond basics: Ready for some fun with the cloning clowns?
Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive