Dolly was the first mammal to be successfully cloned using somatic cell nuclear transfer (SCNT) technology. This technique makes it possible to produce multiple animals from a single donor, and involves transferring the genetic information from a cell from the body of an animal into an empty oocyte, or egg. This process results in an embryo, which is implanted into a surrogate mother, who carries the pregnancy to term.
Nature recently published a piece looking into the "world's most famous sheep." The publication interviewed the team of scientists, led by Roslin embryologist Ian Wilmut, who worked on the Dolly project. It is a notable piece because each scientist provides a first-hand look into the hard work that was put into what would become one of the greatest breakthroughs in animal cloning technology.
The podcast of the interview can be found here.
So where is cloning now? In the decades since Dolly’s birth, scientists have successfully cloned over a dozen other species. These include cows, goats, pigs, horses, mules, deer, mice, cats, dogs, and rare and endangered species including the mouflon, gaur, banteng, and African wildcat.
These advances were made possible by significant improvements in cloning techniques, which have also resulted in a decrease in unique health risks to animal clones. Decades of research and improvement in cloning techniques have resulted in the production of animal clones that are as healthy as conventional animals and those conceived through other forms of assisted reproductive technology.
In its July 5, 2016 piece, 20 Years after Dolly the Sheep Led the Way—Where Is Cloning Now?, Scientific American looks at how "cloning has had a bigger impact on science, but a smaller one on human life." A brief highlight is below:
Cloning a mammal defied the scientific dogma of its time. The success led to dire and fantastic predictions: Humans would be cloned. Diseases would be prevented. Lost children rebirthed. Today, two decades after Dolly’s birth on July 5, 1996, the impact of cloning on basic science has surpassed expectations whereas the reality of what is technically called nuclear transfer—the form of cloning used with Dolly—has largely faded from public consciousness.
In 2016 cloning a person remains unfeasible, with no scientific benefit and an unacceptable level of risk, several scientists say. Most know of no one even considering the feat. And the cloning of animals remains limited—although it is likely growing. Some agricultural cloning is used in the U.S. and China to capitalize on the genes of a few extraordinary specimens, scientists say, but the European Parliament voted last year to ban cloning animals for food. One scientist in South Korea charges $100,000 to clone pets, although the level of demand for the service is unclear.
Cloning’s biggest impact, several researchers say, has been in the stem cell advances it has sparked. Stem cell biologist Shinya Yamanaka said via e-mail that Dolly’s cloning motivated him to begin developing stem cells derived from adult cells—an accomplishment that won him a Nobel Prize in 2012.
“Dolly the Sheep told me that nuclear reprogramming is possible even in mammalian cells and encouraged me to start my own project, wrote Yamanaka, who splits his time between the University of California, San Francisco, and the Center for iPS Cell Research and Application (CiRA) at Kyoto University in Japan, which he directs.
He used adult cells—first in mice, although the technique is now feasible in human cells—to make stem cells that can form a wide range of other cells..Because they are artificially created and can have a variety of futures, they are called induced pluripotent stem (or iPS) cells. The rise of these iPS cells has reduced the need for embryonic stem cells—which have long caused ethical concerns for some—and iPS cells now form the basis for most of today’s stem cell research.
To read the piece in its entirety, visit here.
For more on cloning, visit https://www.bio.org/clone-safety!