The Legacy of Dolly the Sheep May Be Your Future Health

The first mammal cloned from an adult cell, Dolly the sheep. In 1997, The Roslin Institute introduced Dolly to the world. It caused a frenzy of attention. In the twenty-five years since Dolly’s birth, we have cloned many more species of animals with little fanfare. In February 2021, scientists announced they’d successfully cloned the first U.S. endangered species, the black-footed ferret. The ferret is just one part of Dolly’s legacy. The other part of the legacy of Dolly the sheep may be your future health.

Photo of preserved Dolly the Sheep part of a DNA exhibit at  in Edinburgh's Royal Museum. This is also part of Dolly's Legacy.

The Life of Dolly the Cloned Sheep

Born on July 5th 1996, Dolly’s white face confirmed she was a clone. The black-faced surrogate ewe who birthed her could not be her genetic mother.

Scientists tested Dolly’s DNA when she was one. They discovered that her DNA telomeres (end caps) were shorter than expected. Scientists thought that since the cells used to create Dolly came from an adult sheep may have caused the abnormality. They thought the adult cells somehow prevented her telomeres from developing normally.

At two, Dolly mated with a Welsh Mountain ram called David. Dolly gave birth to a female lamb in 1998,. She had twin lambs the next year and triplets in 2000.

In September 2000, Dolly was one of several sheep at The Institute that came down with a sheep retro virus (JSRV). The virus causes lung cancer in sheep.

They diagnosed Dolly with arthritis in 2001 and treated her with anti-inflammatory medications, but never found a cause for her arthritis.

She developed lung cancer and euthanized on February 14, 2003. She was a young six years old. The average life expectancy of her variety of sheep is 11-12. Many feared clones aged faster or didn’t start from age zero.

Dolly’s Legacy—Cloning Endangered Species

Photograph of a wild black-footed ferret. Cloning this endangered species is also part of the legacy of Dolly the sheep

Black-footed ferrets are the only ferret species native to North America. They are also one of North America’s most endangered species. estimates there are approximate 370 black-footed ferrets in the wild today.
Those 370 ferrets are the descendants of seven closely related animals. That lack of genetic diversity will lead to the extinction of these ferrets.

That’s why the February 18, 2021 announcement by the Fish and Wildlife Service’s breeding facility in Fort Collins, Colorado, caused such excitement.

Elizabeth Ann, a black-footed ferret was born on December 10. She was cloned from the frozen remains of a ferret named Willa who died in 1988. If conservationists can reintroduce genetic diversity to the black-footed ferret population, they may prevent the species extinction. They may prevent future extinction if scientists can manipulate the genes to help the animals survive the diseases that endanger them today.

Conservationists and animal lovers celebrate this possibility. But in my post, The Good, the Bad, and the Ugly, I discuss the potential pitfalls of conservation genetics. But conservation genetics is only part of Dolly’s legacy.

Dolly’s Legacy-Rejuvination

image of three strands of DNA colored light blue against a dark blue field. The DNA research done is part of the legacy of Dolly the sheep

An article written in 2016, reported that Dolly had four “sisters” born in 2004. They cloned these sheep from the same genetic material used to clone Dolly. Dolly’s “sisters” are unlike the Azrael in The Fellowship Dystopia series of novels. They were a healthy old age of nine in 2016. The only difference between them and Dolly is that they are kept outside instead of in a barn 24/7.

Scientists confirmed that all signs of biological and chronological age matched between cloned and non-cloned sheep.

There seems to be a natural built-in mechanism in the eggs that can rejuvenate a cell.

If scientists can discover this mechanism, it may lead to cures for many diseases.

Will You Benefit from Dolly’s Legacy?

If scientists could manipulate your genes with a simple treatment or vaccination that cured or prevented diseases like cancer, dementia, arthritis, or chronic pain—would you take the treatment? A huge part of the legacy of Dolly the Sheep may be your future health.

The Good, the Bad, and the Ugly

Conservation Genetics is in the good, the bad, and the ugly spotlight. Conservation Genetics “aims to understand the dynamics of genes in populations principally to avoid extinction.” Clear as mud?

Illustration of a strand of DNA--The good, the bad, the ugly of Conservation Genetics

An Example

It may be easier to understand with an example. Conservation genetics aims to help endangered species, like African cheetahs. Today the existing 10,000 African cheetahs share 99 percent of their DNA. In other words, they’re all related. This means there is little genetic diversity. Low genetic diversity leads to a population that is highly susceptible to disease. Disease that could make the African cheetahs extinct.

Photo of the African cheetah. The Good, the Bad, and the Ugly about Conservation genetics and saving the African cheetah.

Scientists involved with cheetah breeding projects determine how closely related two cheetahs are. They want to reintroduce genetic variety into the population of cheetahs. So, they choose the ones that are the furthest apart genetically and breed those two together. 

If they are successful, the cheetah population will grow. (Source:

Revive & Restore

Revive and Restore is a nonprofit organization. Its mission is to “enhance biodiversity through new techniques of genetic rescue for endangered and extinct species.” One of their funded projects searches for the genomic trigger of bleaching the coral reefs. They say that this study has the “potential opportunity to engineer genomic resilience to climate change. They also hope to de-extinct the Woolly Mammoth.

The Good

Preserving some species (bees?) would be good, even essential, for the survival of the human race. And who would argue against restoring beautiful cats like cheetahs? Or the coral reefs that protect shorelines and provide habitats for many species? 

The Bad: Not a Simple Answer

According to Nature, the early studies of the low genetic variability of the cheetah had many inconsistencies. But those studies brought genetics into conservation efforts and research. Conservationists are learning. They study population decline and inbreeding many near-extinction species. 

The cheetahs are one of many species that have developed low genetic variety despite no evidence of population decline. The authors of the article in Nature caution that scientists may study and manipulate genetic variations that do not matter to the species. 

They suggest that for some species, the low genetic variations during a population decline may be the best genetic survival mechanism for the species. 

The Ugly: Consequences

Conservation genetics is a young discipline. Young enough that they do not know what, beyond selective breeding programs, they might be able to do. 

Even with selective breeding programs, there have been consequences. “when a population of Tatra mountain ibex in Czechoslovakia was ‘enriched’ by new animals from Sinai and Turkey, the offspring inherited an inappropriate calving date, giving birth in mid-winter.” The calves born in the winter died. 

Learning how to de-extinct the Woolly Mammoth may help its current day cousins survive longer. We don’t know what the consequences of de-extincting any species would be. We rarely know the consequences of any new scientific research will be. Does that mean we should abandon new research?


As usual, the ethics discussions lag the scientific discussions and studies. Are conservation genetic efforts “directing evolutionary change?” Is de-extinction of long-gone species, like the Woolly Mammoth, an ethical thing to do? What about saving the coral reef? Or the cheetahs?

We humans are responsible directly and indirectly for the extinction of many species. Does that mean we have a moral duty to restore the species? If that is our moral duty, what about our duty to our species? If we learn enough, we could eradicate some diseases. Should we? Is there a line we should not cross? 

What do You Think?

We merely touched on the good, the bad, and the ugly of Conservation Genetics. Had you heard of conservation genetics before? Will the potential good of conservation genetics outweigh any bad or ugly consequences? Would you de-exterminate the Woolly Mammoth, if you could?

If this post made you think,, you might like to read “Head Transplants.”