GREENWICH, N.Y. — The term clone likely conjures up images that are often reserved for comic books or science-fiction movies. However, in the late 1990s that fiction became a bit more real with the birth of Dolly, the first mammal cloned from an adult cell. Dolly’s birth and life was a scientific breakthrough and big news around the world.
Dolly was the result of research at the Roslin Institute in Edinburgh, Scotland. Led by Professor Ian Wilmut, a team of researchers was studying ways methods to produce genetically modified livestock. The team’s work sought to introduce new genes into livestock which could then be passed on to their offspring. To do this the scientists made attempts to clone a mammal using sheep as their test subjects.
Dolly started out as a single mammary gland cell that came from a six-year-old Finn Dorset sheep. Scientists then combined this cell with the egg cell of a Scottish Blackface sheep that had had its nucleus removed. Once combined, pulses of electricity helped the egg cell accept the new nucleus from the mammary cell, start cell division and commence the development process. This egg cell was then implanted into a Scottish Blackface surrogate sheep where it developed like any other sheep.
Dolly was born on July 5, 1996 and her white face showed that she was genetically different from her black-faced surrogate mother. Her birth was the first success after 277 attempts from the team using the same technique. The sheep was named after the iconic country music star Dolly Parton. According to those who were on the team, the name “Dolly” was chosen because the sheep was formed from a mammary gland cell and Dolly Parton, recognized for her beautiful voice, is also well known for her mammary system.
What made Dolly so important was that she was the first cloned mammal made from a specialized, adult cell. Amphibians and mammals had been cloned before using embryonic and fetal cells. Embryonic cells appear after fertilization and form into the different kinds of specialized cells that comprise an organism. Specialized cells are adult cells that perform a specific task such as heart cells or skin cells. At the time it was believed specialized cells could not be used to form an exact copy of an organism, however the birth of Dolly proved this otherwise. The development of Dolly was something of an accident as Wilmut later said that the adult cells were used as experimental controls and they were not expecting them to be successful.
After keeping her birth under wraps so they could publish their research paper on the project, the team at Roslin unveiled Dolly to the public on February 22, 1997. The announcement brought a tidal wave of media attention. Camera crews and photographers from across the world flocked to Roslin to report on the sheep that was a scientific marvel. In the week after the announcement the Roslin Institute received over 3,000 phone calls!
Dolly’s birth created a sensation among the media and the general public for several years. To many the successful cloning of a mammal with an adult cell appeared to be a seminal moment for science and humanity. People found themselves wondering things like: What other species could be cloned? To what other areas of life could the technology be applied? And, the biggest question of all, could a human being be cloned? With these considerations came others such as if cloning could be done, should it be done? How would cloning effect human life? Dolly’s existence opened many bioethical questions with which governments, scientists, and everyday citizens all grappled.
These ethical matters and fears of the technology being used for wrong purposes led to more oversight. President Bill Clinton prevented federal funds from being used for human cloning. In the years that followed more governmental oversight and funding restrictions were placed on research projects that potentially involved cloning or projects that used cloning technologies like stem cell research.
Despite all the attention Dolly received, the sheep went on to live a normal life. She lived at the Roslin Institute and would have six lambs of her own through the years with a Welsh Mountain Ram named David. Despite living like any other sheep her health faced more scrutiny throughout her life. Analysis of her DNA showed that her telomeres, caps at the end of DNA strands for protection, were shorter leading to questions about whether she was ‘older’ since she was derived from a six-year sheep. Further research found this to be untrue. In 2001 Dolly was diagnosed with arthritis at a relatively young age for a sheep, again leading to questions about her health.
In February 2003 Dolly developed a cough and veterinarians discovered that there were tumors growing on her lungs. Due to this terminal diagnosis Dolly was humanely euthanized at the age of six. The average lifespan of a sheep is 10-12 years. Since Dolly died relatively young it raised questions about the efficacy of cloning animals. Many presumed that since Dolly came from the cell of a six-year-old ewe that she was essentially born at age six and therefore aged faster than a normal sheep. However, Dolly’s death occurred from a naturally occurring problem that was not tied to the fact that she was cloned. Several of Dolly’s “sisters” made from the same cells as she lived longer and healthier lives.
The legacy of Dolly lives on in different ways today. Cloning research continued in other parts of the world with several other kinds of animals being cloned in subsequent years. Some off-shoots of this include pet cloning which is small industry in Asia and the U.S., and research into whether cloning can be used to bring back extinct species like wooly mammoths and dodos.
One of the most significant developments that came from Dolly was the creation of Induced Pluripotent Stem Cells (iPS). Using technology inspired by the project that created Dolly a team led by Japanese scientist Shinya Yamanaka was able to create iPS cells which are adult cells that are reprogrammed to revert to their embryonic stage making it possible for them to become other kinds of cells. This has the potential to advance the field of regenerative medicine while avoiding the controversial use of human embryonic stem cells which were typically used in such research before iPS cells were available.
In the world of agriculture cloning is used today on a smaller scale mainly by high-end livestock breeders. The process is used to help preserve the traits of elite animals though it is very expensive and not always successful. In 2008 the FDA allowed the use of cloning in cattle, pigs, and goats and their offspring for meat and milk production. Food from cloned animals is deemed safe by the FDA and does not need to be labeled. The practice is not allowed in Europe, however, as the European Union prohibited the cloning of farm animals in 2015.
Though Dolly’s life was short she captured the world’s attention. Her development opened the door for the possibility of a wide range of scientific and medical advances and brought to the forefront important questions regarding science & technology and its effects on humanity. Questions that remain in the public consciousness with any scientific advancement and not just cloning. After her death Dolly was preserved and is on display at the National Museum of Scotland in Edinburgh today.
Chandler Hansen grew up and lives in Easton, NY. He is a graduate of Gordon College where he earned a bachelor’s degree in History. He serves as a writer and editor for Morning Ag Clips.
