pros and cons of animal cloning

The Pros and Cons of Animal Cloning

In 1996, a pair of scientists at the Roslin Institute at the University of Edinburgh embarked on an audacious venture. Taking the somatic cell from a 6-year-old Finn-Dorset ewe, biologists Dr. Keith Campbell and Sir Ian Wilmut inserted it in the ovum harvested from another sheep. After 276 attempts, an embryo was successfully seeded, then placed inside a third female sheep, where it underwent the gestation period typical of any normal pregnancy. 

On July 5, 1996, scientists’ bold undertaking became a roaring success when “Dolly the Sheep,” the first successfully cloned mammal, was born. 

Called the “world’s most famous sheep,” Dolly lived with her human creators at the Roslin Institute. Bred with a Welsh Mountain Ram, Dolly would produce six lambs before finally being euthanized at 6.5 years old due to progressive lung disease and severe arthritis. Dolly’s taxidermied remains are now on display at the National Museum of Scotland

The taxidermied remains of Dolly the Sheep at the National Museum of Scotland (Image Source: Wikicommons)

Fast forward twenty-five years. Not wanting to be outdone by NASA’s successful landing of the Perseverance Rover on Mars, on February 18, 2021, officials with the U.S. Fish and Wildlife Service announced they had successfully cloned the first U.S. endangered species, a black-footed ferret named Elizabeth Ann. 

Looking at the photos released by Fish and Wildlife, with her adorable black eye markings resembling a robber’s mask, I had to fight the sudden urge to don a loincloth and fight an evil wizard army with Elizabeth Ann as my ever loyal side-kick, à la Beastmaster-style. However, there is one eerie difference between Elizabeth Ann the ferret and Dolly the Sheep.


Unlike Dolly, who technically had three living “mothers,” Elizabeth Ann was created using extracted cells from a black-footed ferret that had died 33 years prior. 

Born December 10, 2020, Elizabeth Ann is a genetic copy of a ferret named Willa, who died in 1988. At the time of her death, DNA technology was just in its infancy. Yet, astute (or mad) scientists froze the endangered ferret’s body, where it lay in cryogenic impassiveness, waiting until the day Willa could be “reborn.” 

Those who are already a bit squeamish with the 18 different mammal species geneticists have cloned in the past 20 years – including Mice, Pigs, Cattle, Cats, Rats, Mules, Horses, Dogs, Wolf, Water Buffalo, Goats, Camel, and even monkeys – scientist’s necromancy with Elizabeth Ann the ferret is likely pretty alarming. 

In hopes of gaining a better understanding of what feels like machiavellian-science, The Debrief takes a look at some of the pros and cons of animal cloning. 

pros and cons of animal cloning
Elizabeth Ann, the black-footed ferret cloned from cells of a deceased ferret by U.S. Fish and Wildlife scientists. (Image Source: U.S. Fish and Wildlife Service)


The Pros and Cons of Animal Cloning 

It’s important to note up-front, the process of reproducing by sharing virtually identical DNA sequences does occur naturally. Living in clonal colonies, plants, fungi, and single-celled organisms, such as bacteria, have been reproducing asexually for hundreds of millions of years. 

Contrary to how it may look, recent research published in the journal of Nature Genetics shows that monozygotic or “identical” twins are not clones. After sequencing DNA from 387 pairs of identical twins, scientists found that mutations during early gestation create genetic differences in identical twins. On average, identical twins have 5.2 early genetic differences between each other. 

To examine some of the pros and cons of animal cloning, the term “cloning” here doesn’t refer to natural asexual reproduction or colloquialism. Instead, “cloning” refers to the method of artificial replication of identical cells, or DNA fragments, used to create a life that would otherwise reproduce sexually. 

Grey wolves and animal cloning
(Image Source: Pixabay)


Maintaining Ecological Balance and Saving Endangered Species 

Two decades ago, Yellowstone National Park was in a state of ecological crisis. 

Expansion of agriculture, the decimation of the American bison population, and government predator control programs had all but wiped out the Grey Wolf in the continental United States. With the apex predator on the brink of extinction, deer and elk populations dramatically increased, resulting in overgrazing. With deer and elk gobbling up vegetation important to soil and riverbank structure with impunity, the landscape became highly vulnerable to erosion. 

Recognizing the national park’s ecosystem’s elasticity was on the brink of collapse, in 1995, conservationists reintroduced the grey wolf to Yellowstone, and suddenly everything changed. 

As a top predator, conservationists discovered wolves were one of the significant linchpins holding together the balance between predator and prey in Yellowstone’s ecosystem. Removal of the wolves had disrupted the food chain causing something called a trophic cascade

Without facing the threat of a natural predator, deer and elk populations had multiplied to the point where they were consuming more foliage than the habitat could sustain. Consequently, the reintroduction of grey wolves to Yellowstone reduced the population numbers and changed their preys’ behavior. 

Deer and elk began avoiding the valleys and gorges at Yellowstone, where the wolves could easily hunt them. In turn, thanks to the revived food source of vegetation, these areas began to flourish with species such as birds, beavers, mice, foxes, and bears. The thriving plant life along the riverbanks caused erosion to decrease significantly.

Lessons learned from Yellowstone were that even the loss of just one species could have a cascading and catastrophic effect on an entire habitat and the environment. 

Given the devastating positive or negative effect just one species can have, consider for some, cloning is very literally the only way we might be able to save them from extinction. Take, for example, the white rhinoceros.

white rhinos cloning
The world’s last two known remaining white rhinos Fatu (left) and Najin (right) at the Ol Pejeta Conservancy in Kenya. (Image Source: Helping


The world’s last known male white rhinoceros named Sudan died in Kenya in March of 2018. The only two confirmed white rhinos left are two females, Fau, 18, and Najin, 29, living in captivity in Kenya’s Ol Pejeta Conservancy. 

Without a male rhino to mate with, when Fau and Najin finally pass away, their entire species die with them. In hopes of preventing this demise, researchers have successfully taken frozen sperm extracted from two male rhinos after their deaths and inseminated it into eggs harvested from Fatu and Najin. As of 2020, three white rhino embryos have been generated, kept frozen until they can be placed in a surrogate female. 

As was demonstrated in the case of Dolly, cloned animals can still reproduce naturally to produce offspring. So the goal of cloning high-risk endangered species serves as an intervention. The end goal of cloning high-risk endangered species like the white rhino is to see the animals thrive and sustain themselves naturally and not be kept alive by human life-support. 

As is the case with Elizabeth Ann, cloning an endangered species could allow the animals to be reintroduced into a habitat to offset potential damage caused by their demise. With some critically endangered animals like the white rhino, cloning is simply the only method of saving species from complete extinction. 

So when it comes to the pros and cons of animal cloning, from the perspective of rescuing an entire species from extinction, it’s hard to make a case that animal cloning is a bad thing. 

Now, Elizabeth Ann’s DNA came from an animal that had been dead for over three decades, so her cloning might seem understandably creepy. However, though endangered, the black-footed ferret does indeed exist in limited populations in the wild. This brings us to the next question when examining the pros and cons of animal cloning. 

Could we resurrect a species that was already extinct, and if so, what could happen? 

pros and cons of animal cloning
(Image Source: Pixabay)


Cloning Already Extinct Animals 

When it comes to the pros and cons of animal cloning, anyone who’s watched the movie franchise Jurassic Park is intimately familiar with the potential negative outcome of cloning extinct species. 

So what would happen if scientists cloned an animal that had long been extinct, like the saber-toothed tiger, woolly mammoth, or as is the case in Jurassic Park, a Velociraptor or Tyrannosaurus Rex? 

Fortunately for anyone who’s seen the habitual outcome in the movies (or unfortunately, if your thinking happens to align with the wealthy eccentric fictional character, John Hammond), resurrecting long-extinct dinosaurs is impossible. “The limit of DNA survival, which we’d need for de-extinction, is probably around one million years or less. Dinosaurs had been gone for a very long time by then,” said Dr. Beth Shapiro, an expert in ancient DNA and biologist at the University of California. 

Even though the outcome always ends in tragedy, at least in the movies, one can’t help but feel a little let down by the news that we’ll never get a chance to see Earth’s ancient reptile rulers up close. 

Nevertheless, with dinosaurs off the table, there are still many species that have gone extinct we might be able to clone. There happens to be an entire scientific discipline called “resurrection biology” that examines doing just that. 

If you have not previously heard of resurrection biology, which sounds more like sorcery than science, you’re likely equally unfamiliar with the fact that scientists have already reanimated a species that had gone extinct. Albeit very briefly. 

Pyrenean ibex
The now extinct Pyrenean ibex. (Image Source: Save The Earth.World)


In 2000, the Pyrenean ibex, a goat native to the Pyrenees, was declared extinct. Given that by 1913, ecologists already knew the species population had been reduced to less than 100, its loss has been called a significant “EU conservation failure.” 

Yet, using skin cells from the last known ibex, which had died in late 1999, scientists were able to successfully make cloned embryos by inserting the ibex’s DNA into domestic goat eggs emptied of their original genetic material. 

The cloned embryos were then implanted into another subspecies of Spanish ibex or goat-ibex hybrids. Of 208 implanted embryos, seven goats became pregnant, with just one making it to term. On July 30, 2003, the first-ever cloned extinct species was born. 

Unfortunately, the Pyrenean ibex’s revival in the animal kingdom only lasted a few minutes. The newborn ibex had been born with an extra lobe in its left lung, causing the kid to succumb to respiratory distress syndrome and die six minutes after it was born. So far, researchers have not successfully cloned the Pyrenean ibex, and the mountain goat remains extinct. 

The difficulty in cloning a species is hardly limited to the Pyrenean ibex. With current technology, the act of shuffling DNA from one cell to another, causing developmental irregularities and abnormalities, is prevalent. 

Even when cells can be extracted and a cloned embryo successfully cultivated, scientists have to overcome another huge obstacle when working with an extinct species. There aren’t any appropriate surrogate mothers. 

Underscoring the difficulties in resurrecting an extinct species, consider with the Pyrenean ibex, researchers had the benefit of beginning their attempts almost immediately after the last goat died. Attempting to clone a species that has been gone for tens-to-hundreds-of-thousands of years is exceedingly more difficult. 

In fact, rather than using the process of somatic cell nuclear transfer – how Dolly the Sheep and Elizabeth Ann were created – to attempt the resurrection of an extinct species, scientists must engage in a process in which DNA is inserted, deleted, modified, or replaced in the genome of an organism. This technique is called genome editing or genome engineering. 

Due to controversies surrounding the topic and an often contentious public view, many are probably familiar with the term describing an organism’s successful genetic editing for increased food yield – GMO (genetically modified organism)

To revive an animal long wiped out, resurrection biologists have to use cells from a closely related species and then modify those cells so that a living species produce offspring of an extinct species. A species that is at the forefront of de-extinction science right now is the woolly mammoth

Disappearing roughly 3,700 years ago, scientists have well preserved soft tissue remains and DNA from woolly mammoths. Unfortunately, even the most intact mammoth samples lack enough DNA to guide the production of an embryo. To overcome this, scientists have been examining using new molecular tools to edit the genomes of elephants to alter their DNA sequences to mammoth DNA. If successful, the result wouldn’t be a woolly mammoth clone, but rather a hybrid that would be mostly elephant, and a little bit mammoth. 

“If you mean 100-percent mammoth, with all mammoth genes and behaviors, that will never happen,” says Dr. Shapiro on the likelihood of ever fully cloning a woolly mammoth. 

If an extinct species can never really be restored, is there any reason for de-extinction outside of novelty? 

woolly mammoth
Artist rendition of the extinct woolly mammoth (Image Source PBS)


A June 2013 editorial by Scientific American criticized efforts to reanimate lost species on the basis the idea misses the mark when it comes to conservation. Editors argued that with “limited intellectual bandwidth and financial resources,” the attention-grabbing de-extinction topic diverts attention from the current biodiversity crisis. 

“A program to restore extinct species poses a risk of selling the public on a false promise that technology alone can solve our ongoing environmental woes—an implicit assurance that if a species goes away, we can snap our fingers and bring it back.” 

As far as pros and cons of animal cloning, the Scientific American editors said they stood behind efforts to prevent extinction, highlighting the black-footed ferret and white rhino as examples. 

Responding to the criticism raised by Scientific American, professor of genetics at Harvard Medical School and Director of the National Institutes of Health Center of Excellence in Genomic Science at Harvard, Dr. George Church, clapped back, suggesting the authors were the ones missing the point. 

For Dr. Church, it goes back to the grey wolves and Yellowstone National Park and the evidence of how impactful one “keystone” species can be, not just to one habitat but the entire world’s ecosystem. 

Thousands of years ago, the ice-covered tundras of Russia and Canada was home to the woolly mammoth. During that time, the area was home to a rich grass-and-ice-based ecosystems. Today, those tundras are melting, and according to Dr. Church, if this continues, it could release more greenhouse gas “than all the world’s forest would if they were burned to the ground.” 

A few genetic modifications to the modern elephant’s DNA could create a hybrid animal functionally similar to the mammoth. By reintroducing woolly mammoth hybrids to the tundras, the animals could single-handedly stave off an environmental crisis.

In an essay published in Scientific American, Church outlines three significant ways mammoth hybrids would restore balance to the world’s coldest regions. 

  1. Eating dead grass, enabling the sun to reach spring grass, whose deep roots prevent erosion. 
  2. Increasing reflected light by felling trees, which absorb sunlight. 
  3. Punching through insulating snow so that freezing air penetrates the soil. 

Dr. Church provides a compelling case for why cloning for de-extinction is far from a novelty. As grey wolves demonstrated, the woolly mammoth’s return could have a significant positive impact on our planet’s ecology. However, objectively it’s essential to remember this is entirely uncharted territory for humanity, with considerable unknowns. 

Reintroducing a species that has been extinct for thousands of years could have the exact opposite effect as the grey wolf. An extinct species could easily be viewed as an invasive species by its former habitat. Instead of restoring balance, it could throw-off an ecosystem in ways we didn’t foresee. 

Given the ongoing and over a year-long struggle the world has endured with the COVID-19 pandemic, it’s also important to consider that reintroducing extinct animals could end up creating new opportunities for bacteria and viruses to develop. Even if a species was merely a hybrid, it’s hard to predict whether that might be enough to reinvigorate the conditions to foster ancient bacterial strains. Equally unknown, to what effect could archaic bacteria have on human health? 

Ultimately, there are theoretical arguments on both sides when it comes to the pros and cons of animal cloning of extinct animals. However, too many unknowns prevent us from truly knowing which side of the scale weighs the heaviest. 

pros and cons of animal cloning
(Image Source: Pixabay)


Pros and Cons of Animal Cloning For Food 

Thus far, we’ve examined the pros and cons of animal cloning that can indirectly impact people’s daily lives. However, whether you realize it or not, it’s highly likely you’ve been experiencing the byproducts of animal cloning for years and didn’t even know it. 

With the breakthrough cloning of Dolly the Sheep, agricultural scientists realized cloning could duplicate prize breeding animals. Facing the potential to ensure greater yields and better meats, by the early 2000s, an entire industry surrounding the genetic modification of cows, pigs, and goats exploded on the scene. 

In truth, cloning is an expensive venture, so the overwhelming majority of livestock clones are used as breeding stock and not butchered for meat. Yet, it’s almost sure that aside from vegans, everyone has dined on beef that has come from the cloned offspring.

In 2008, the U.S. Food and Drug Administration (FDA) declared meat and milk from clones of cattle, swine, and goats to be “as safe to eat as food from conventionally bred animals.” Adding insult to injury for those expressing concerns, the FDA ruled that cloned food is not required to be labeled, preventing consumers’ ability to avoid meats coming from cloned animals. 

Criticizing the conclusions of the FDA’s 2008 “risk assessment,” opponents have argued cloning science is too new, not well understood, and too imprecise to adequately measure the risks. 

Pointing to their own study, the Center for Food Safety notes that even the FDA acknowledged in their risk assessment that “a vast quantity of animal clones are unhealthy and would not be suitable for the food supply.” 

Critics say that acknowledging the majority of cloned animals is not suitable for food supply but still approving the process for consumption; the FDA fails to address that defects in cloned animals can easily escape detection and enter human food supplies. A study performed by the National Academy of Sciences (NAS) concluded that no method for detecting subtle health problems in clones exists. 

As the market for cloned livestock took off in the early 2000s, Sir Ian Wilmut, lead research scientist that cloned Dolly the Sheep, expressed his reservations concerning science he helped develop being used for genetically enhanced foods. “Cattle cloners ought to be making systematic comparisons between clones and animals produced by embryo transfer, looking not just at their milk yield but also their health and lifespan,” said Wilmut. 

A 2013 study concluded that cloned cattle that reached adulthood and entered the food supply were essentially equivalent to conventional cattle concerning meat and milk quality. 

Consumer advocates also raise many concerns about the high doses of hormones and antibiotics used in the cloning process. Surprisingly little research has been done on the health effects of hormones used with cloned livestock, so the impact on human health isn’t entirely clear. 

Because the practice hasn’t been around long enough, the potential for adverse long-term effects from cloned food consumption is even less clear. 

Advocates of animal husbandry cloning contend the process allows for exact genetic copies of top breeding stock to be replicated, thereby producing healthier, superior livestock. 

“Cloning reproduces the healthiest animals, thus minimizing the use of antibiotics, growth hormones and other chemicals,” reads a statement provided by the Biotechnology Industry Organization. “Consumers can benefit from cloning because meat and milk will be more healthful, consistent, and safe.” 

Like resurrecting long-dead species, the pros and cons of animal cloning for food sources are difficult to measure. The majority of public opinion has never polled favorably regarding cloning and animal husbandry. However, that alone doesn’t necessitate the practice is inherently harmful. 

Ultimately, unlike de-extinction cloning, livestock’s genetic engineering is very much a significant part of the modern agricultural industry. Whether or not this is a good or bad thing is a consequence we’ll likely have to live with, no matter the outcome. 

We’ve examined the pros and cons of animal cloning and how it affects human beings and the environment. However, the most contentious slippery slope surrounding the entire topic of animal cloning is the ethical debate and the potential negative consequences on the very animal life being used. 


pros and cons of animal cloning
Cloned macaque monkeys are almost genetically identical, and share a mutation that disrupts their sleep cycle. (Image Source: Institute of Neuroscience, Chinese Academy of Sciences)


Ethical Pros and Cons of Animal Cloning 

Is it morally right to create a life that would not otherwise come about naturally? When it comes to the pros and cons of animal cloning, this isn’t a question that can be answered by science or ground truth. As is the case with all moral issues, the ethical terrain surrounding animal cloning is complex. 

Yet, it’s arguably the most crucial question that vexes the public and genetic scientists alike. 

For some, there exists a principled argument against humanity effectively playing God, choosing life and death over other living creatures. For others, the ethical concerns center on more nuanced yet tangible and disturbingly brazen aspects of animal cloning. 

Arguably, the most compelling moral argument is the genuine suffering often endured by the animals involved in genetic science. The pain and suffering animals experience during cloning procedures, obstetrical complications that occur with surrogate mothers, and cloned animals’ health are genuine issues. 

Success rates of cloning procedures in producing live offspring, called “efficiency” in cloning science, are pretty grim. Studies have shown the differing efficiency rates based on the somatic cell type used, ranging from 30% to 93%, of clone pregnancies resulting in miscarriages. A separate study found that less than 5% of cloned embryos transferred into recipient cows survive. 

When live-births occur,  research has shown mortality rates to be as high as 50%. Basically, a coin toss decides if a cloned animal ends up dying within 130 days due to chronic health issues. 

The overwhelming bulk of past research on animal cloning involves examining the efficiency rates of somatic cell transfer, which currently shows success rates of 5%-20% for cows and 1%-5% for other species. Little research, however, exits on the health of cloned animals into adulthood. 

2016 study on cloned sheep, including four from the same cell lines as Dolly, found no evidence of late-onset, non-communicable diseases. “We could find no evidence, therefore, of a detrimental long-term effect of cloning by SCNT on the health of aged offspring among our cohort,” said the study’s authors. 

In light of the researcher’s findings, the proverbial elephant in the room is that when Dolly passed away at 6.5 years old from lung disease and severe arthritis, she had only lived around half of the typical 12-year life expectancy of a Finn Dorset sheep. 

Some speculated Dolly could have been born with the genetic age of the cell donor used to create her, who was six at the time of cell transfer. Researchers, however, said they found no evidence of Dolly being born at an advanced age, and her heirs have all gone on to live long, healthy lives. 

pros and cons of animal cloning
(Image Source:Institute of Neuroscience, Chinese Academy of Sciences)


Adding an entirely new wrinkle in the ethical pros and cons of animal cloning, in 2019, scientists at the Institute of Neuroscience (ION) in Shanghai announced they had successfully cloned five identical macaque monkeys. As if cloning human beings’ primate cousins weren’t already concerning, Chinese scientists purposefully cloned the macaque monkeys to suffer health issues. 

To unravel the mechanisms behind complex human disorders, such as Alzheimer’s, scientists at ION used gene-editing to disable a gene crucial to the monkey’s sleep-wake cycle. “Primates are the best animal model for studying higher cognitive functions and brain disorders in humans,” said neuroscientist Mu-ming Poo, ION’s director, and co-founder. 

With their five identical cloned monkeys, researchers at ION intend to study the effects of circadian rhythm disorders in hopes of better understanding and ultimately finding cures for human beings who suffer from sleep disorders. 

Initial results of the study on circadian rhythms using the cloned monkeys were published in the journal of National Science Review – of which Mu-ming Poo is Executive Editor-in-Chief. Poo said researchers did this because “the journal needs publicity” but denied being involved in the review process. 

An animal ethics statement published with the study reads, “The use and care of cynomolgus monkeys (Mfascicularis) complied with the guidelines of the Animal Advisory Committee at the Shanghai Institutes for Biological Science, Chinese Academy of Sciences.” 

In 2019, Poo said Chinese researchers were already planning to use cloned primates to model other brain diseases, such as Alzheimer’s disease, Parkinson’s disease, a severe genetic intellectual disability called Angelman syndrome, and several genetic eye disorders. 

A statement issued by the People for the Ethical Treatment of Animals (PETA), an animal rights group based in Norfolk, Virginia, called ION’s research “a monstrous practice that causes [the monkeys] to suffer.” 

pros and cons of animal cloning
(Image Source:Institute of Neuroscience, Chinese Academy of Sciences)

Whether it be for conservation, de-extinction, livestock use, or medical research, proponents solve animal cloning’s moral question by the adage, “the ends justify the means.” Specifically, the benefit to humanity through animal cloning outweighs any suffering and health-risk, or even purposeful manipulation to cause disease, caused through the cloning process. 

It’s vital to be abundantly clear. Just like the editors of Scientific American advocated using animal cloning for the conservation of endangered species, but shunned de-extinction, there is no single ethical solution amongst the varied domains of cloning science. 

The Debrief set out to examine the pros and cons of animal cloning. However, once one digs into the topic, one finds there is no simple answer. There is no universal conclusion as to whether cloning is fundamentally a positive or negative thing. 

There are compelling arguments on both sides, with some avenues, such as cloning for conservation, seemingly more acceptable. In these instances, realizing the alternative means the loss of an entire species can mitigate the pain, suffering, or low “efficiency” involved in the process. 

Meanwhile, other areas, such as cloning for medical research, even when that research may benefit humankind, leave one with a sense of disgust and simply feel morally wrong. 

Some may argue that science is the quest for objective knowledge and should be divorced from ethical considerations. However, this view discounts the fact that, as the pursuers of knowledge, human beings are creatures capable of taking a holistic view and considering the broader consequences of their actions. 

Going back to Yellowstone National Park’s case, the overpopulation of deer and elk caused the depletion of natural resources, negatively impacting the entire ecosystem. Yet, these acts were not immoral, and the animals were incapable of measuring the consequences of their overconsumption. 

Conversely, human beings cannot claim such ignorance. We are more than capable of discerning the impact of our actions on ourselves and the world around us. We must use that holistic lens when examining animal cloning to measure risk vs. reward, both in the near and short term, and the principled impact on society. 

Ultimately, Dr. Shapiro best sums up the dilemma of animal cloning in her book, How to Clone a Mammoth: The Science of De-Extinction. Describing her work examining how to resurrect extinct species, Dr. Shapiro calls it “Exhilarating because of the unprecedented opportunities to understand life and boost conservation efforts, but terrifying in part for its ethical quandaries.”

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Posted by The Debrief on Thursday, February 25, 2021