Valentine's Day Proves Fatal for Dolly
||Bert Thompson, Ph.D.
Brad Harrub, Ph.D.
“Dolly’s lung problem was the last in a series of medical problems. Last year, Ian Wilmut, the Roslin researcher who led the team that cloned her, said that had he been a hill farmer and Dolly a regular sheep, the size of the vet’s bill would already have sealed her fate” (Whitfield, 2003, emp. added). Dr. Wilmut never had to load his gun. On February 14, 2003, Dolly, the world’s first cloned sheep (and first mammal ever cloned from an adult cell), was euthanized after being diagnosed with progressive lung disease, reported the Roslin Institute, where Dolly was cloned in 1996 (see “First Cloned Sheep…”, 2003). Dolly’s obituary read like a Hollywood headline: “Celebrity clone dies of drug overdose” (Whitfield, 2003). The “official” obituary noted that she was only six-and-a-half years old, and had suffered “from lung cancer caused by a virus” (Whitfield). A postmortem examination was carried out, and preliminary results revealed that the world-famous sheep also was suffering from both cancer and arthritis. Dolly’s final resting place will be at the National Museum of Scotland in Edinburgh, where, according to scientists at the Roslin Institute in Midlothian where Dolly had been kept, she eventually will be put on public display. This chapter in the life of this legendary sheep may be closed, but Dolly’s early demise assures that many more chapters will be written as we try to determine the safety and efficacy of cloning—in both animals and humans.
Health concerns had plagued Dolly from the very beginning of her unusual life. Early on, researchers were worried that Dolly had a serious weight problem. Then, in 1999, a development occurred that made her excessive weight seem—if you’ll pardon the pun—not so “weighty.” This milestone in the cloning controversy was reported in the May 27, 1999 issue of Nature, where Dr. Wilmut discussed his examination of Dolly’s chromosomes. Wilmut and his colleagues studied the length of chromosome ends (telomeres) from Dolly and two other sheep produced by the same process (known as “nuclear somatic transfer”) that had been used to clone Dolly. It generally has been accepted scientifically that telomere deterioration is a reliable indication of reduction in life span; the more rapid and serious the telomere deterioration, the shorter the expected life span. Wilmut and his coworkers reported a marked deterioration in the telomeres of Dolly’s chromosomes, compared to those from non-cloned animals, and even suggested that “the most likely explanation” for the deterioration observed in these animals “reflects that of the transferred nucleus. Full restoration of telomere length did not occur because these animals were produced without germline involvement” (see Shiels, et al., 1999, 399:317, emp. added).
In other words, since Dolly was cloned from the mammary gland cell of a six-year-old sheep, in essence her telomeres already were six years old, and therefore deteriorated more rapidly than those of non-cloned animals produced by regular procreative procedures. In simple terms, it may turn out that cloned creatures have markedly reduced life spans compared to those produced via normal, sexual reproduction. In fact, in January 2002, it was reported that Dolly was suffering from severe arthritis. At the time, Dr. Wilmut noted: “There is no way of knowing if this is due to cloning or whether it is a coincidence” (see BBC News, 2002). In that same article, the author noted that the director of an organization known as Compassion in World Farming, Joyce D’Silva, told BBC Radio 5 Live:
I think of the hundreds and hundreds of other cloned lambs who have been born and had malformed hearts, lungs, or kidneys. They have struggled to survive for a few days and then had their lungs filled with fluid and gasped their way to death or had to be put out of their misery by their creators. That is the real story of cloning.
One year after Dolly had been diagnosed with arthritis, on Valentine’s Day (February 14), 2003, the almost-seven-year-old sheep had to be euthanized due to a progressive lung disease—an infection seen mainly in older sheep. The point should not be overlooked that Dolly was created from the cell of a six-year-old sheep, and that she died approximately six years early. If the findings from Dr. Wilmut and other researchers are confirmed, this obviously will have serious implications for attempts at human cloning. If a 65-year-old man had himself cloned (to choose just one example), the clone just might begin life with a 65-year head start toward the grave!
Dolly’s untimely death follows the announcement that Matilda, Australia’s first cloned sheep (born April 2000, and the first sheep to be cloned outside of the Roslin Institute—see CBC News, 2003), died. Rob Lewis, the South Australian Research Institute’s executive director, said that Matilda seemed “remarkably healthy” on the day she died. Sadly, Matilda’s corpse already was decomposing when it was discovered; thus, researchers cremated it—never identifying the true cause of death. These reports echo previous ones regarding the life expectancy of clones. For instance, on March 9, 2001, three cattle cloned by scientists at California State University at Chico appeared to have been born healthy, but two of the calves died of abrupt immune system failure, and the third was reported to be failing rapidly (see Cooper, 2001). While not widely reported in the news media, such events are becoming quite common in regard to cloned animals, and serve to demonstrate the potential dangers of human cloning. Many of the animals that have been cloned have experienced obvious mutations, while others have died shortly after birth, even though outwardly they appeared to be quite normal (see, for example, Humphreys, 2001). In studies performed on cloned cattle by Cyagra, Inc., a Kansas company that studies the commercial aspects of cloning livestock, the “company has about a 6 percent birth rate; of those calves, about half die soon after they are born” (as quoted in Cooper, 2001).
An unsettling report in the July 6, 2001 issue of Science addressed this very point, and documented the fact that while cloned animals may appear normal, and may even behave somewhat normal, the truth is that sometimes these animals are far from normal. The report went on to announce that scientists have found the first evidence that “normal-looking” clones can harbor serious genetic abnormalities. For those researchers interested in pursuing cloning as an alternate method of reproduction, the news from scientists at the Whitehead Institute for Biomedical Research and the University of Hawaii represented a veritable bomb detonated right on their very doorsteps. The first statement in a paper titled “Epigenetic Instability in ES Cells and Cloned Mice” by David Humphreys and colleagues reads as follows: “Cloning by nuclear transfer is an inefficient process in which most clones die before birth and survivors often display growth abnormalities” (2001, 293:95, emp. added).
One year later, Tanja Dominko of the Oregon Regional Primate Research Centre, spoke at a conference in Washington, D.C., where she reported on her work with cloned monkey embryos. She commented that the cloned embryos showed a host of problems, and that even embryos that looked healthy were, to use her words, a “gallery of horrors” (see Westphal, 2001, 172:14). This is not exactly the image of cloning that federally funded researchers want the public at large to see.
One thing is certain. Scientists do not want Dolly’s death stifling the agenda for human cloning. In fact, two days after Dolly’s death, Robin McKie wrote a paper titled “Dolly Dies—But Human Cloning will Still Happen.” McKie noted: “Human cloning is still on the agenda. Leading scientists yesterday attacked suggestions that the early death of Dolly the Sheep showed that current biotechnology techniques were inefficient and unworkable” (2003). Thus, the push continues for someone to announce to a waiting world—and provide definitive proof—that they have successfully cloned the world’s first human. We invite you to read an in-depth investigation into just what the cloning process entails in considering whether or not humans should be cloned. For additional information on cloning click here.
BBC News (2002), “Cloned Sheep Dolly Has Arthritis,” [On-line], URL: http://news.bbc.co.uk/2/hi/science/nature/1741559.stm, January 4.
CBC News (2003), “Australia’s First Cloned Ewe Dies Mysteriously,” [On-line], URL: http://www.cbc.ca/stories/2003/02/07/matilda030207, February 7.
Cooper, Audrey (2001), “Cloned Calves Die at California University,” [On-line], URL: http://www.canoe.ca/CNEWSScience0104/03_cow-ap.html.
“Experts Doubt Human Clone Claim by Raelians” (2002), [On-line], URL: http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/1040346511396_34/?hub=SciTech.
“First Cloned Sheep Dolly Dies at 6,” (2003), [On-line] URL: http://edition.cnn.com/2003/WORLD/Europe/02/14/cloned.dolly.dies/, February 14.
Humphreys, David, et al., (2001), “Epigenetic Instability in ES Cells and Cloned Mice,” Science, 293:95-97, July 6.
McKie, Robin (2003), “Dolly Dies—But Human Cloning Will Still Happen,” The Observer [On-line], URL: http://www.observer.co.uk/uk_news/story/0,6903,896566,00.html, February 16.
Shiels, P.G., A.J. Kind, K.H.S. Campbell, D. Waddington, I. Wilmut, A. Colman, and A.E. Schnieke (1999), “Analysis of Telomere Lengths in Cloned Sheep,” Nature, 399:316-317, May 27.
Westphal, Sylvia Pagan (2001), “Impossible to Ape: Cloning Primates is Turning Out to be a Real Chal-lenge,” New Scientist, 172:14, December 15.
Whitfield, John (2003), “Obituary: Dolly the Sheep,” Nature Science Update, [On-line], URL: http://www.nature.com/nsu/030217/0303217-6.html, February 18.