In 1997 a Scottish research institute revealed that it had successfully cloned a sheep from an adult cell.
The sheep's name was Dolly, and her creation would shock the world and be instrumental for medical science.
[00:00:00] Hello, hello hello, and welcome to English Learning for Curious Minds, by Leonardo English.
[00:00:12] The show where you can listen to fascinating stories, and learn weird and wonderful things about the world at the same time as improving your English.
[00:00:21] I'm Alastair Budge, and today we are going to be talking about Dolly the Sheep, probably the most famous sheep in the world.
[00:00:30] 25 years ago this year, in 1997, a small research institute in Scotland announced that it had cloned a sheep from a single adult cell.
[00:00:43] The birth of Dolly was groundbreaking for many reasons, and it gave rise to both fear and suspicion.
[00:00:51] Would cloning become widespread? How long would it be until we started cloning humans? Had we gone too far and started to develop God-like powers?
[00:01:02] It seemed like humanity was on the very cusp of entering a new era that would change life, and its creation, as we knew it.
[00:01:11] But, behind the media hype on cloning humans, Dolly’s creation had enormous implications for science and our understanding of cell programming and genetic diseases.
[00:01:24] So, that’s what we are going to talk about today, the story of how a Scottish research team and a cloned sheep took the world by surprise, how it actually worked, and what has happened since then.
[00:01:38] OK then, let’s get started, and talk about Dolly the Sheep.
[00:01:44] Dolly was created at the Roslin Institute in Scotland, an institute for animal research.
[00:01:51] The team of researchers there was trying to find better ways of creating genetically modified farm animals. Dolly was just one of their many experiments, but she would undoubtedly be the most famous.
[00:02:06] Dolly was born in July of 1996, but her birth was not made public, it wasn’t announced publicly, until seven months later.
[00:02:17] This delay gave the institute a chance to publish its scientific paper on the methods used to create Dolly at the same time as it announced Dolly to the world.
[00:02:27] It was a huge development, and in the week after Dolly was announced the otherwise quiet phone lines at the Roslin Institute received 3,000 phone calls from all over the world.
[00:02:42] Her face was all over the news, all around the world, and in an instant she became the most famous sheep in history.
[00:02:51] So, why was Dolly the Sheep such a big deal?
[00:02:55] Well, she was special, but contrary to what many people think she wasn’t actually the first cloned animal, or even the first cloned mammal.
[00:03:06] Cloning, the creation of an identical genetic copy of an organism, has a surprisingly long scientific history.
[00:03:15] The first creature to be demonstrably cloned, to be cloned in a way that can be proved, was a sea urchin more than 100 years before Dolly, in 1885.
[00:03:27] Sea urchins, by the way, are those small, spikey sea animals you find on a sea bed. They are fairly basic creatures so it’s easy to study their development.
[00:03:39] Researchers found that by simply shaking sea urchins at a very early stage of their development, their cells would separate to form an additional identical sea urchin - a process known as artificial embryo twinning.
[00:03:56] It just so happened that sea urchins were very easy to clone. Larger animals would prove to be more complicated.
[00:04:04] In 1975, cloning experiments were made using rabbit embryos, an embryo being the very first form of an animal or human at its earliest stages of growth.
[00:04:17] After transferring a rabbit embryo cell into an egg, a process known as nuclear transfer, an advanced rabbit embryo was grown in a laboratory in Oxford.
[00:04:29] The embryo was not grown to its full potential, no rabbit was actually born, as this would have required placing the embryo inside a female rabbit.
[00:04:40] This, however, was the first time a mammal embryo had been created via nuclear transfer, but it was still restricted to the laboratory. Scientists needed to figure out a way of getting the embryo into a host mother, so that it could grow to full term, and be born.
[00:05:00] The first records of this were in the 1980s, when sheep and cattle were cloned using the nuclear transfer technique.
[00:05:09] The embryos created in laboratories were implanted, or placed inside, host animal mothers which resulted in live births.
[00:05:18] It's pretty amazing technologically, but it was actually quite simple compared to Dolly.
[00:05:25] So, let’s move on to Dolly the Sheep, the hero, or should I say heroine, of our story.
[00:05:32] Just how was she created, and why was this so important?
[00:05:37] Dolly was created with the help of three individual female sheep, or ewes.
[00:05:44] Sheep one, sheep two, and sheep three. It’s particularly important that all three of them were female, there were no male sheep involved in the creation of Dolly.
[00:05:57] Cells were taken from sheep one’s breast tissue, which would provide the DNA.
[00:06:04] Incidentally, it was because Dolly the Sheep’s DNA came from breast tissue that she was named Dolly, after Dolly Parton the American country singer.
[00:06:15] If this explanation doesn’t make sense to you, then if you search for images of “Dolly Parton” then perhaps it’ll be more clear.
[00:06:24] So, sheep one provided the DNA which Dolly was to be cloned from. Importantly, this came from this sheep’s breast tissue.
[00:06:34] As you will know, DNA contains all of the genetic instructions needed to grow, maintain and reproduce an organism.
[00:06:43] In other words, it’s almost like a biological recipe book.
[00:06:48] This is important as it’ll be sheep one that will provide the DNA for Dolly; sheep one and Dolly will be genetically identical, they will be the same. It's also important to note that the cells used were from an adult sheep and they were what’s called specialised cells.
[00:07:09] Specialised cells are different from the cells that are used to create life.
[00:07:14] Specialised cells have been developed to fulfil a specialised role, for example in the case of Dolly, breast tissue cells.
[00:07:23] At the very beginning of the creation of a person or animal, we start off as a single cell that divides and divides and divides, eventually creating an embryo.
[00:07:34] This early collection of cells, called embryonic stem cells, are not specialised. They will go on to create every type of cell that our body needs.
[00:07:45] Dolly started off as a single specialised adult cell in a test tube. The scientists at the Roslin Institute were trying to create a new being from an adult specialised cell.
[00:07:58] This was previously thought to be impossible.
[00:08:02] Once the breast tissue cell was successfully isolated, separated, from the other cells, the next step was to insert it into an egg cell provided by sheep number two.
[00:08:16] This egg was unfertilised, it couldn’t create a lamb, a baby sheep.
[00:08:21] Scientists removed the cell’s nucleus, its centre, that contained the genetic material.
[00:08:28] They then replaced the nucleus with the adult breast cell from sheep one.
[00:08:34] This, perhaps, might sound simple, but it is, of course, a very complex process and various other steps are required.
[00:08:42] In fact, it took 227 attempts to produce Dolly.
[00:08:49] Of all these breast cells implanted into egg cells, only 13 successfully formed into embryos.
[00:08:57] These 13 developing embryos were inserted into surrogate ewes, mother sheep.
[00:09:04] Only one became pregnant, sheep three, who gave birth to Dolly.
[00:09:10] The scientists could immediately see that Dolly was indeed a clone of sheep one because sheep one was a breed of sheep with a white face, whereas sheep two and three had a black face. When Dolly was born she had a white face, indicating she was completely unrelated to sheep two or three, and was an exact replica of sheep number one.
[00:09:35] So, now that we've got an idea of what was involved in Dolly’s creation, we can move on to focus on the importance of this development.
[00:09:44] What made Dolly’s creation such a scientific breakthrough?
[00:09:49] What developments have been made as a result of the science behind cloning Dolly the sheep?
[00:09:54] In other words, why was Dolly so important?
[00:09:58] As we discussed earlier, cloning mammals was certainly not new.
[00:10:04] What made Dolly’s case so special was that an exact genetic replica of sheep one, a mammal, had been engineered and brought to life from an adult specialised cell.
[00:10:17] The fact that a sheep, a mammal, had been cloned from a single adult cell seemed to open up a huge realm of cloning possibilities in the not so distant future.
[00:10:29] If sheep, then theoretically any mammal, including humans, could be cloned.
[00:10:35] The unthinkable had been done. Pandora’s box had been opened and it seemed like the world had changed forever and there was no going back.
[00:10:44] Pope John Paul II criticised Dolly’s creation as being a “dangerous experiment” and called for a ban on cloning humans.
[00:10:54] The World Health Organisation released a statement denouncing human cloning as being "ethically unacceptable and contrary to human integrity and morality".
[00:11:05] Scientists were accused of playing God and there was a huge amount of controversy, of disagreement, about the future of cloning.
[00:11:15] Yet despite the intense media frenzy, or excitement, about the seemingly very near prospect of human cloning, the advances made by Dolly’s research team have not led to a world filled with cloned humans, let alone the great increase in cloning that was predicted.
[00:11:35] Why not, you might ask.
[00:11:37] Well, although scientists believe it could theoretically be possible, it would be inadvisable, and there simply isn’t the will to try it.
[00:11:46] It doesn’t mean that there haven’t been some developments though.
[00:11:50] Indeed, a human embryonic clone was successfully created in 2013 using DNA from skin cells, and two monkeys were successfully cloned in China in 2018, using the same technique as for Dolly.
[00:12:06] This suggests that the same technique that created Dolly the Sheep could potentially be used in humans.
[00:12:13] But human cloning was and still is considered to be too dangerous and completely unethical.
[00:12:22] Approximately 46 countries have banned human cloning, although some of these countries still allow human embryo cloning for research purposes despite bans on human reproductive cloning.
[00:12:35] There seems to be a general consensus, an agreement, that attempting to create a human clone, also known as reproductive cloning, is unacceptable. However, in the USA, despite powerful anti-cloning religious influences, there are actually no laws regulating human cloning at a federal level.
[00:12:59] In the UK, reproductive cloning is banned. Therapeutic cloning, cloning human embryos to research the development of genetic diseases, and embryonic cloning for stem cell research, are both allowed but highly regulated.
[00:13:15] At the UN and in the European Union, there is no clear consensus on creating fully binding laws that ban cloning. Some European countries allow cloning for therapeutic and stem cell research, as do many countries in Asia.
[00:13:32] It seems that the awkward questions about the creation of life that Dolly the Sheep has generated are still very far from being adequately resolved - both legally and ethically.
[00:13:45] This being said, Dolly’s creation and the process used have been invaluable to science.
[00:13:53] Indeed, the original purpose of creating Dolly was to help scientists to better understand and cure diseases in humans, not to clone them.
[00:14:04] The main benefit of Dolly’s creation has been the advances made in the field of cell research.
[00:14:11] Prior to, before, the creation of Dolly, scientists believed that once cells had become specialised they completely lost their ability to be able to be reprogrammed to produce other types of cells.
[00:14:26] What Dolly had proved was that cellular nuclear reprogramming is indeed possible - in other words that we can turn back time in terms of the development of specialised cells to reproduce stem cells from specialised ones.
[00:14:42] You’ve probably heard the term “stem cell” before, but here’s a quick explanation, which will help you understand why Dolly was so important.
[00:14:52] Stem cells are the very special type of cell that have the potential, the ability, to develop into many different types of cells. Stem cells can replicate, they can divide into exact copies of themselves, forming more cells, known as daughter cells.
[00:15:12] You can think of stem cells as being the very building blocks of life itself.
[00:15:18] They provide the raw materials required to produce all other types of cells in the body.
[00:15:24] Previously, research into stem cells required embryonic stem cells, cells from a human embryo, which understandably raises a huge amount of ethical concerns.
[00:15:37] When scientists clone human embryonic stem cells for use in the lab, there’s an argument that they are creating a human being, giving themselves God-like powers.
[00:15:49] Even if the embryos they are using are really only the starting point of life, a microscopically small bunch of cells, they could theoretically become humans like you and me.
[00:16:01] Understandably, not many people are comfortable with the idea of humans being created for research purposes.
[00:16:09] So here’s where the importance of Dolly comes in.
[00:16:13] The creation of Dolly showed that we can create artificial stem cells from adult cells using blood or skin tissue, without having to clone human embryos.
[00:16:26] This means that scientists can run experiments on these artificially created stem cells, helping us better understand diseases, without the same ethical dilemma of cloning human embryos.
[00:16:41] Indeed, this technology was used to create the genetically modified heart in the first pig-to-human heart transplant.
[00:16:50] As you can create these artificial stem cells using a patient's own cells, it is becoming increasingly possible to create more personalised treatments for diseases, as well as reducing the chances of rejection when growing organs for transplantation.
[00:17:08] Obviously, this is good news for medical science.
[00:17:12] But Dolly’s legacy expands further than just the medical world.
[00:17:17] Cloning animals has continued to develop as an industry.
[00:17:21] Particularly desirable farm animals are starting to be cloned, so that animals with valuable characteristics can continue to breed.
[00:17:31] This mainly takes place in China and the USA - the cloning of animals used for food has been banned in Europe.
[00:17:40] Some types of animals that are bordering on extinction have also been cloned to try to prevent them from dying out as a species.
[00:17:48] You may have heard tales about bringing back mammoths, or even dinosaurs, from the dead using cloning, just like they did to create Dolly.
[00:17:58] This is now more of a possibility than ever before, provided we have DNA that has been well preserved.
[00:18:06] While not quite as impressive as a T-Rex, scientists in America have already successfully cloned an endangered type of American ferret, a small furry mammal, using cells from a deceased, a dead, individual.
[00:18:22] In addition, there are also various companies around the world that specialise in the cloning of pets for wealthy owners, people whose favourite dog or cat has died and they are prepared to pay tens if not hundreds of thousands of dollars for a carbon copy of it.
[00:18:42] So, now we’ve discussed the importance of Dolly’s creation and its implications, what about the actual sheep herself?
[00:18:50] We’ve really skipped over our main character, haven’t we?
[00:18:54] Well, the reality is that, although Dolly’s existence was remarkable, her life itself was pretty unremarkable.
[00:19:04] She was a sheep, she got up in the morning, she ate grass, and did what every other sheep in the world does.
[00:19:11] Dolly lived with a flock of other sheep, some cloned, some non-cloned, and went on to have six lambs, all fathered naturally by the same ram, the male sheep.
[00:19:24] Unfortunately, Dolly developed arthritis - the disease that causes the joints to become swollen, causing pain and stiffness.
[00:19:33] Older sheep often suffer with arthritis, it’s not uncommon at all, however, Dolly was only middle-aged when she first started showing signs of stiffness.
[00:19:45] In 2003, her handlers noticed that she was coughing frequently. A scan revealed that she had a severe disease that causes lung cancer in sheep, again not uncommon at all.
[00:19:58] But she was old and unwell, and it was decided to put her to sleep, to euthanise her, while she was still unconscious during the scan.
[00:20:09] There were some fears that Dolly’s ill health, or sickness, could be linked to her being a clone, and that her arthritis could be linked to premature ageing.
[00:20:20] However, out of the other Dolly clones that were later made from the same cell culture, only one sheep appeared to develop moderate arthritis.
[00:20:30] So, it may well have just been bad luck.
[00:20:34] To conclude, Dolly the Sheep has inspired some of the most important recent developments in genetic modification and biotechnology.
[00:20:43] While the hype, the excitement, surrounding her creation and the fears that it produced have faded, the improvements in science that she directly inspired have been truly groundbreaking.
[00:20:56] Dolly the Sheep was living proof that adult cells could be reprogrammed to make stem cells.
[00:21:03] Thanks to the work of the team at the Roslin Institute, we are a step closer to understanding and ultimately curing some of the most serious and debilitating diseases.
[00:21:14] And, contrary to what the fear mongers might have said back in 1997, the world is not filled with human clones, dinosaurs are not roaming the streets of London and New York, and in fact all that happened was that a very unordinary sheep ended up living a very ordinary life.
[00:21:35] OK then, that is it for today's episode on Dolly the Sheep.
[00:21:41] I hope it’s been an interesting one, and that you’ve learned a little bit about the science behind cloning as well as some of the important advances that Dolly’s creation has inspired.
[00:21:51] As always, I would love to know what you thought about this episode.
[00:21:55] What are your thoughts on human cloning?
[00:21:57] Are there any circumstances in which you think it should be allowed, or should it be completely banned?
[00:22:03] What about animal cloning for agricultural or medical purposes?
[00:22:08] How do you think stem cell therapy could change our lives in the future?
[00:22:13] I would love to know, so let’s get this discussion started.
[00:22:16] You can head right into our community forum, which is at community.leonardoenglish.com and get chatting away to other curious minds.
[00:22:25] You've been listening to English Learning for Curious Minds, by Leonardo English.
[00:22:30] I'm Alastair Budge, you stay safe, and I'll catch you in the next episode.
[END OF EPISODE]
[00:00:00] Hello, hello hello, and welcome to English Learning for Curious Minds, by Leonardo English.
[00:00:12] The show where you can listen to fascinating stories, and learn weird and wonderful things about the world at the same time as improving your English.
[00:00:21] I'm Alastair Budge, and today we are going to be talking about Dolly the Sheep, probably the most famous sheep in the world.
[00:00:30] 25 years ago this year, in 1997, a small research institute in Scotland announced that it had cloned a sheep from a single adult cell.
[00:00:43] The birth of Dolly was groundbreaking for many reasons, and it gave rise to both fear and suspicion.
[00:00:51] Would cloning become widespread? How long would it be until we started cloning humans? Had we gone too far and started to develop God-like powers?
[00:01:02] It seemed like humanity was on the very cusp of entering a new era that would change life, and its creation, as we knew it.
[00:01:11] But, behind the media hype on cloning humans, Dolly’s creation had enormous implications for science and our understanding of cell programming and genetic diseases.
[00:01:24] So, that’s what we are going to talk about today, the story of how a Scottish research team and a cloned sheep took the world by surprise, how it actually worked, and what has happened since then.
[00:01:38] OK then, let’s get started, and talk about Dolly the Sheep.
[00:01:44] Dolly was created at the Roslin Institute in Scotland, an institute for animal research.
[00:01:51] The team of researchers there was trying to find better ways of creating genetically modified farm animals. Dolly was just one of their many experiments, but she would undoubtedly be the most famous.
[00:02:06] Dolly was born in July of 1996, but her birth was not made public, it wasn’t announced publicly, until seven months later.
[00:02:17] This delay gave the institute a chance to publish its scientific paper on the methods used to create Dolly at the same time as it announced Dolly to the world.
[00:02:27] It was a huge development, and in the week after Dolly was announced the otherwise quiet phone lines at the Roslin Institute received 3,000 phone calls from all over the world.
[00:02:42] Her face was all over the news, all around the world, and in an instant she became the most famous sheep in history.
[00:02:51] So, why was Dolly the Sheep such a big deal?
[00:02:55] Well, she was special, but contrary to what many people think she wasn’t actually the first cloned animal, or even the first cloned mammal.
[00:03:06] Cloning, the creation of an identical genetic copy of an organism, has a surprisingly long scientific history.
[00:03:15] The first creature to be demonstrably cloned, to be cloned in a way that can be proved, was a sea urchin more than 100 years before Dolly, in 1885.
[00:03:27] Sea urchins, by the way, are those small, spikey sea animals you find on a sea bed. They are fairly basic creatures so it’s easy to study their development.
[00:03:39] Researchers found that by simply shaking sea urchins at a very early stage of their development, their cells would separate to form an additional identical sea urchin - a process known as artificial embryo twinning.
[00:03:56] It just so happened that sea urchins were very easy to clone. Larger animals would prove to be more complicated.
[00:04:04] In 1975, cloning experiments were made using rabbit embryos, an embryo being the very first form of an animal or human at its earliest stages of growth.
[00:04:17] After transferring a rabbit embryo cell into an egg, a process known as nuclear transfer, an advanced rabbit embryo was grown in a laboratory in Oxford.
[00:04:29] The embryo was not grown to its full potential, no rabbit was actually born, as this would have required placing the embryo inside a female rabbit.
[00:04:40] This, however, was the first time a mammal embryo had been created via nuclear transfer, but it was still restricted to the laboratory. Scientists needed to figure out a way of getting the embryo into a host mother, so that it could grow to full term, and be born.
[00:05:00] The first records of this were in the 1980s, when sheep and cattle were cloned using the nuclear transfer technique.
[00:05:09] The embryos created in laboratories were implanted, or placed inside, host animal mothers which resulted in live births.
[00:05:18] It's pretty amazing technologically, but it was actually quite simple compared to Dolly.
[00:05:25] So, let’s move on to Dolly the Sheep, the hero, or should I say heroine, of our story.
[00:05:32] Just how was she created, and why was this so important?
[00:05:37] Dolly was created with the help of three individual female sheep, or ewes.
[00:05:44] Sheep one, sheep two, and sheep three. It’s particularly important that all three of them were female, there were no male sheep involved in the creation of Dolly.
[00:05:57] Cells were taken from sheep one’s breast tissue, which would provide the DNA.
[00:06:04] Incidentally, it was because Dolly the Sheep’s DNA came from breast tissue that she was named Dolly, after Dolly Parton the American country singer.
[00:06:15] If this explanation doesn’t make sense to you, then if you search for images of “Dolly Parton” then perhaps it’ll be more clear.
[00:06:24] So, sheep one provided the DNA which Dolly was to be cloned from. Importantly, this came from this sheep’s breast tissue.
[00:06:34] As you will know, DNA contains all of the genetic instructions needed to grow, maintain and reproduce an organism.
[00:06:43] In other words, it’s almost like a biological recipe book.
[00:06:48] This is important as it’ll be sheep one that will provide the DNA for Dolly; sheep one and Dolly will be genetically identical, they will be the same. It's also important to note that the cells used were from an adult sheep and they were what’s called specialised cells.
[00:07:09] Specialised cells are different from the cells that are used to create life.
[00:07:14] Specialised cells have been developed to fulfil a specialised role, for example in the case of Dolly, breast tissue cells.
[00:07:23] At the very beginning of the creation of a person or animal, we start off as a single cell that divides and divides and divides, eventually creating an embryo.
[00:07:34] This early collection of cells, called embryonic stem cells, are not specialised. They will go on to create every type of cell that our body needs.
[00:07:45] Dolly started off as a single specialised adult cell in a test tube. The scientists at the Roslin Institute were trying to create a new being from an adult specialised cell.
[00:07:58] This was previously thought to be impossible.
[00:08:02] Once the breast tissue cell was successfully isolated, separated, from the other cells, the next step was to insert it into an egg cell provided by sheep number two.
[00:08:16] This egg was unfertilised, it couldn’t create a lamb, a baby sheep.
[00:08:21] Scientists removed the cell’s nucleus, its centre, that contained the genetic material.
[00:08:28] They then replaced the nucleus with the adult breast cell from sheep one.
[00:08:34] This, perhaps, might sound simple, but it is, of course, a very complex process and various other steps are required.
[00:08:42] In fact, it took 227 attempts to produce Dolly.
[00:08:49] Of all these breast cells implanted into egg cells, only 13 successfully formed into embryos.
[00:08:57] These 13 developing embryos were inserted into surrogate ewes, mother sheep.
[00:09:04] Only one became pregnant, sheep three, who gave birth to Dolly.
[00:09:10] The scientists could immediately see that Dolly was indeed a clone of sheep one because sheep one was a breed of sheep with a white face, whereas sheep two and three had a black face. When Dolly was born she had a white face, indicating she was completely unrelated to sheep two or three, and was an exact replica of sheep number one.
[00:09:35] So, now that we've got an idea of what was involved in Dolly’s creation, we can move on to focus on the importance of this development.
[00:09:44] What made Dolly’s creation such a scientific breakthrough?
[00:09:49] What developments have been made as a result of the science behind cloning Dolly the sheep?
[00:09:54] In other words, why was Dolly so important?
[00:09:58] As we discussed earlier, cloning mammals was certainly not new.
[00:10:04] What made Dolly’s case so special was that an exact genetic replica of sheep one, a mammal, had been engineered and brought to life from an adult specialised cell.
[00:10:17] The fact that a sheep, a mammal, had been cloned from a single adult cell seemed to open up a huge realm of cloning possibilities in the not so distant future.
[00:10:29] If sheep, then theoretically any mammal, including humans, could be cloned.
[00:10:35] The unthinkable had been done. Pandora’s box had been opened and it seemed like the world had changed forever and there was no going back.
[00:10:44] Pope John Paul II criticised Dolly’s creation as being a “dangerous experiment” and called for a ban on cloning humans.
[00:10:54] The World Health Organisation released a statement denouncing human cloning as being "ethically unacceptable and contrary to human integrity and morality".
[00:11:05] Scientists were accused of playing God and there was a huge amount of controversy, of disagreement, about the future of cloning.
[00:11:15] Yet despite the intense media frenzy, or excitement, about the seemingly very near prospect of human cloning, the advances made by Dolly’s research team have not led to a world filled with cloned humans, let alone the great increase in cloning that was predicted.
[00:11:35] Why not, you might ask.
[00:11:37] Well, although scientists believe it could theoretically be possible, it would be inadvisable, and there simply isn’t the will to try it.
[00:11:46] It doesn’t mean that there haven’t been some developments though.
[00:11:50] Indeed, a human embryonic clone was successfully created in 2013 using DNA from skin cells, and two monkeys were successfully cloned in China in 2018, using the same technique as for Dolly.
[00:12:06] This suggests that the same technique that created Dolly the Sheep could potentially be used in humans.
[00:12:13] But human cloning was and still is considered to be too dangerous and completely unethical.
[00:12:22] Approximately 46 countries have banned human cloning, although some of these countries still allow human embryo cloning for research purposes despite bans on human reproductive cloning.
[00:12:35] There seems to be a general consensus, an agreement, that attempting to create a human clone, also known as reproductive cloning, is unacceptable. However, in the USA, despite powerful anti-cloning religious influences, there are actually no laws regulating human cloning at a federal level.
[00:12:59] In the UK, reproductive cloning is banned. Therapeutic cloning, cloning human embryos to research the development of genetic diseases, and embryonic cloning for stem cell research, are both allowed but highly regulated.
[00:13:15] At the UN and in the European Union, there is no clear consensus on creating fully binding laws that ban cloning. Some European countries allow cloning for therapeutic and stem cell research, as do many countries in Asia.
[00:13:32] It seems that the awkward questions about the creation of life that Dolly the Sheep has generated are still very far from being adequately resolved - both legally and ethically.
[00:13:45] This being said, Dolly’s creation and the process used have been invaluable to science.
[00:13:53] Indeed, the original purpose of creating Dolly was to help scientists to better understand and cure diseases in humans, not to clone them.
[00:14:04] The main benefit of Dolly’s creation has been the advances made in the field of cell research.
[00:14:11] Prior to, before, the creation of Dolly, scientists believed that once cells had become specialised they completely lost their ability to be able to be reprogrammed to produce other types of cells.
[00:14:26] What Dolly had proved was that cellular nuclear reprogramming is indeed possible - in other words that we can turn back time in terms of the development of specialised cells to reproduce stem cells from specialised ones.
[00:14:42] You’ve probably heard the term “stem cell” before, but here’s a quick explanation, which will help you understand why Dolly was so important.
[00:14:52] Stem cells are the very special type of cell that have the potential, the ability, to develop into many different types of cells. Stem cells can replicate, they can divide into exact copies of themselves, forming more cells, known as daughter cells.
[00:15:12] You can think of stem cells as being the very building blocks of life itself.
[00:15:18] They provide the raw materials required to produce all other types of cells in the body.
[00:15:24] Previously, research into stem cells required embryonic stem cells, cells from a human embryo, which understandably raises a huge amount of ethical concerns.
[00:15:37] When scientists clone human embryonic stem cells for use in the lab, there’s an argument that they are creating a human being, giving themselves God-like powers.
[00:15:49] Even if the embryos they are using are really only the starting point of life, a microscopically small bunch of cells, they could theoretically become humans like you and me.
[00:16:01] Understandably, not many people are comfortable with the idea of humans being created for research purposes.
[00:16:09] So here’s where the importance of Dolly comes in.
[00:16:13] The creation of Dolly showed that we can create artificial stem cells from adult cells using blood or skin tissue, without having to clone human embryos.
[00:16:26] This means that scientists can run experiments on these artificially created stem cells, helping us better understand diseases, without the same ethical dilemma of cloning human embryos.
[00:16:41] Indeed, this technology was used to create the genetically modified heart in the first pig-to-human heart transplant.
[00:16:50] As you can create these artificial stem cells using a patient's own cells, it is becoming increasingly possible to create more personalised treatments for diseases, as well as reducing the chances of rejection when growing organs for transplantation.
[00:17:08] Obviously, this is good news for medical science.
[00:17:12] But Dolly’s legacy expands further than just the medical world.
[00:17:17] Cloning animals has continued to develop as an industry.
[00:17:21] Particularly desirable farm animals are starting to be cloned, so that animals with valuable characteristics can continue to breed.
[00:17:31] This mainly takes place in China and the USA - the cloning of animals used for food has been banned in Europe.
[00:17:40] Some types of animals that are bordering on extinction have also been cloned to try to prevent them from dying out as a species.
[00:17:48] You may have heard tales about bringing back mammoths, or even dinosaurs, from the dead using cloning, just like they did to create Dolly.
[00:17:58] This is now more of a possibility than ever before, provided we have DNA that has been well preserved.
[00:18:06] While not quite as impressive as a T-Rex, scientists in America have already successfully cloned an endangered type of American ferret, a small furry mammal, using cells from a deceased, a dead, individual.
[00:18:22] In addition, there are also various companies around the world that specialise in the cloning of pets for wealthy owners, people whose favourite dog or cat has died and they are prepared to pay tens if not hundreds of thousands of dollars for a carbon copy of it.
[00:18:42] So, now we’ve discussed the importance of Dolly’s creation and its implications, what about the actual sheep herself?
[00:18:50] We’ve really skipped over our main character, haven’t we?
[00:18:54] Well, the reality is that, although Dolly’s existence was remarkable, her life itself was pretty unremarkable.
[00:19:04] She was a sheep, she got up in the morning, she ate grass, and did what every other sheep in the world does.
[00:19:11] Dolly lived with a flock of other sheep, some cloned, some non-cloned, and went on to have six lambs, all fathered naturally by the same ram, the male sheep.
[00:19:24] Unfortunately, Dolly developed arthritis - the disease that causes the joints to become swollen, causing pain and stiffness.
[00:19:33] Older sheep often suffer with arthritis, it’s not uncommon at all, however, Dolly was only middle-aged when she first started showing signs of stiffness.
[00:19:45] In 2003, her handlers noticed that she was coughing frequently. A scan revealed that she had a severe disease that causes lung cancer in sheep, again not uncommon at all.
[00:19:58] But she was old and unwell, and it was decided to put her to sleep, to euthanise her, while she was still unconscious during the scan.
[00:20:09] There were some fears that Dolly’s ill health, or sickness, could be linked to her being a clone, and that her arthritis could be linked to premature ageing.
[00:20:20] However, out of the other Dolly clones that were later made from the same cell culture, only one sheep appeared to develop moderate arthritis.
[00:20:30] So, it may well have just been bad luck.
[00:20:34] To conclude, Dolly the Sheep has inspired some of the most important recent developments in genetic modification and biotechnology.
[00:20:43] While the hype, the excitement, surrounding her creation and the fears that it produced have faded, the improvements in science that she directly inspired have been truly groundbreaking.
[00:20:56] Dolly the Sheep was living proof that adult cells could be reprogrammed to make stem cells.
[00:21:03] Thanks to the work of the team at the Roslin Institute, we are a step closer to understanding and ultimately curing some of the most serious and debilitating diseases.
[00:21:14] And, contrary to what the fear mongers might have said back in 1997, the world is not filled with human clones, dinosaurs are not roaming the streets of London and New York, and in fact all that happened was that a very unordinary sheep ended up living a very ordinary life.
[00:21:35] OK then, that is it for today's episode on Dolly the Sheep.
[00:21:41] I hope it’s been an interesting one, and that you’ve learned a little bit about the science behind cloning as well as some of the important advances that Dolly’s creation has inspired.
[00:21:51] As always, I would love to know what you thought about this episode.
[00:21:55] What are your thoughts on human cloning?
[00:21:57] Are there any circumstances in which you think it should be allowed, or should it be completely banned?
[00:22:03] What about animal cloning for agricultural or medical purposes?
[00:22:08] How do you think stem cell therapy could change our lives in the future?
[00:22:13] I would love to know, so let’s get this discussion started.
[00:22:16] You can head right into our community forum, which is at community.leonardoenglish.com and get chatting away to other curious minds.
[00:22:25] You've been listening to English Learning for Curious Minds, by Leonardo English.
[00:22:30] I'm Alastair Budge, you stay safe, and I'll catch you in the next episode.
[END OF EPISODE]
[00:00:00] Hello, hello hello, and welcome to English Learning for Curious Minds, by Leonardo English.
[00:00:12] The show where you can listen to fascinating stories, and learn weird and wonderful things about the world at the same time as improving your English.
[00:00:21] I'm Alastair Budge, and today we are going to be talking about Dolly the Sheep, probably the most famous sheep in the world.
[00:00:30] 25 years ago this year, in 1997, a small research institute in Scotland announced that it had cloned a sheep from a single adult cell.
[00:00:43] The birth of Dolly was groundbreaking for many reasons, and it gave rise to both fear and suspicion.
[00:00:51] Would cloning become widespread? How long would it be until we started cloning humans? Had we gone too far and started to develop God-like powers?
[00:01:02] It seemed like humanity was on the very cusp of entering a new era that would change life, and its creation, as we knew it.
[00:01:11] But, behind the media hype on cloning humans, Dolly’s creation had enormous implications for science and our understanding of cell programming and genetic diseases.
[00:01:24] So, that’s what we are going to talk about today, the story of how a Scottish research team and a cloned sheep took the world by surprise, how it actually worked, and what has happened since then.
[00:01:38] OK then, let’s get started, and talk about Dolly the Sheep.
[00:01:44] Dolly was created at the Roslin Institute in Scotland, an institute for animal research.
[00:01:51] The team of researchers there was trying to find better ways of creating genetically modified farm animals. Dolly was just one of their many experiments, but she would undoubtedly be the most famous.
[00:02:06] Dolly was born in July of 1996, but her birth was not made public, it wasn’t announced publicly, until seven months later.
[00:02:17] This delay gave the institute a chance to publish its scientific paper on the methods used to create Dolly at the same time as it announced Dolly to the world.
[00:02:27] It was a huge development, and in the week after Dolly was announced the otherwise quiet phone lines at the Roslin Institute received 3,000 phone calls from all over the world.
[00:02:42] Her face was all over the news, all around the world, and in an instant she became the most famous sheep in history.
[00:02:51] So, why was Dolly the Sheep such a big deal?
[00:02:55] Well, she was special, but contrary to what many people think she wasn’t actually the first cloned animal, or even the first cloned mammal.
[00:03:06] Cloning, the creation of an identical genetic copy of an organism, has a surprisingly long scientific history.
[00:03:15] The first creature to be demonstrably cloned, to be cloned in a way that can be proved, was a sea urchin more than 100 years before Dolly, in 1885.
[00:03:27] Sea urchins, by the way, are those small, spikey sea animals you find on a sea bed. They are fairly basic creatures so it’s easy to study their development.
[00:03:39] Researchers found that by simply shaking sea urchins at a very early stage of their development, their cells would separate to form an additional identical sea urchin - a process known as artificial embryo twinning.
[00:03:56] It just so happened that sea urchins were very easy to clone. Larger animals would prove to be more complicated.
[00:04:04] In 1975, cloning experiments were made using rabbit embryos, an embryo being the very first form of an animal or human at its earliest stages of growth.
[00:04:17] After transferring a rabbit embryo cell into an egg, a process known as nuclear transfer, an advanced rabbit embryo was grown in a laboratory in Oxford.
[00:04:29] The embryo was not grown to its full potential, no rabbit was actually born, as this would have required placing the embryo inside a female rabbit.
[00:04:40] This, however, was the first time a mammal embryo had been created via nuclear transfer, but it was still restricted to the laboratory. Scientists needed to figure out a way of getting the embryo into a host mother, so that it could grow to full term, and be born.
[00:05:00] The first records of this were in the 1980s, when sheep and cattle were cloned using the nuclear transfer technique.
[00:05:09] The embryos created in laboratories were implanted, or placed inside, host animal mothers which resulted in live births.
[00:05:18] It's pretty amazing technologically, but it was actually quite simple compared to Dolly.
[00:05:25] So, let’s move on to Dolly the Sheep, the hero, or should I say heroine, of our story.
[00:05:32] Just how was she created, and why was this so important?
[00:05:37] Dolly was created with the help of three individual female sheep, or ewes.
[00:05:44] Sheep one, sheep two, and sheep three. It’s particularly important that all three of them were female, there were no male sheep involved in the creation of Dolly.
[00:05:57] Cells were taken from sheep one’s breast tissue, which would provide the DNA.
[00:06:04] Incidentally, it was because Dolly the Sheep’s DNA came from breast tissue that she was named Dolly, after Dolly Parton the American country singer.
[00:06:15] If this explanation doesn’t make sense to you, then if you search for images of “Dolly Parton” then perhaps it’ll be more clear.
[00:06:24] So, sheep one provided the DNA which Dolly was to be cloned from. Importantly, this came from this sheep’s breast tissue.
[00:06:34] As you will know, DNA contains all of the genetic instructions needed to grow, maintain and reproduce an organism.
[00:06:43] In other words, it’s almost like a biological recipe book.
[00:06:48] This is important as it’ll be sheep one that will provide the DNA for Dolly; sheep one and Dolly will be genetically identical, they will be the same. It's also important to note that the cells used were from an adult sheep and they were what’s called specialised cells.
[00:07:09] Specialised cells are different from the cells that are used to create life.
[00:07:14] Specialised cells have been developed to fulfil a specialised role, for example in the case of Dolly, breast tissue cells.
[00:07:23] At the very beginning of the creation of a person or animal, we start off as a single cell that divides and divides and divides, eventually creating an embryo.
[00:07:34] This early collection of cells, called embryonic stem cells, are not specialised. They will go on to create every type of cell that our body needs.
[00:07:45] Dolly started off as a single specialised adult cell in a test tube. The scientists at the Roslin Institute were trying to create a new being from an adult specialised cell.
[00:07:58] This was previously thought to be impossible.
[00:08:02] Once the breast tissue cell was successfully isolated, separated, from the other cells, the next step was to insert it into an egg cell provided by sheep number two.
[00:08:16] This egg was unfertilised, it couldn’t create a lamb, a baby sheep.
[00:08:21] Scientists removed the cell’s nucleus, its centre, that contained the genetic material.
[00:08:28] They then replaced the nucleus with the adult breast cell from sheep one.
[00:08:34] This, perhaps, might sound simple, but it is, of course, a very complex process and various other steps are required.
[00:08:42] In fact, it took 227 attempts to produce Dolly.
[00:08:49] Of all these breast cells implanted into egg cells, only 13 successfully formed into embryos.
[00:08:57] These 13 developing embryos were inserted into surrogate ewes, mother sheep.
[00:09:04] Only one became pregnant, sheep three, who gave birth to Dolly.
[00:09:10] The scientists could immediately see that Dolly was indeed a clone of sheep one because sheep one was a breed of sheep with a white face, whereas sheep two and three had a black face. When Dolly was born she had a white face, indicating she was completely unrelated to sheep two or three, and was an exact replica of sheep number one.
[00:09:35] So, now that we've got an idea of what was involved in Dolly’s creation, we can move on to focus on the importance of this development.
[00:09:44] What made Dolly’s creation such a scientific breakthrough?
[00:09:49] What developments have been made as a result of the science behind cloning Dolly the sheep?
[00:09:54] In other words, why was Dolly so important?
[00:09:58] As we discussed earlier, cloning mammals was certainly not new.
[00:10:04] What made Dolly’s case so special was that an exact genetic replica of sheep one, a mammal, had been engineered and brought to life from an adult specialised cell.
[00:10:17] The fact that a sheep, a mammal, had been cloned from a single adult cell seemed to open up a huge realm of cloning possibilities in the not so distant future.
[00:10:29] If sheep, then theoretically any mammal, including humans, could be cloned.
[00:10:35] The unthinkable had been done. Pandora’s box had been opened and it seemed like the world had changed forever and there was no going back.
[00:10:44] Pope John Paul II criticised Dolly’s creation as being a “dangerous experiment” and called for a ban on cloning humans.
[00:10:54] The World Health Organisation released a statement denouncing human cloning as being "ethically unacceptable and contrary to human integrity and morality".
[00:11:05] Scientists were accused of playing God and there was a huge amount of controversy, of disagreement, about the future of cloning.
[00:11:15] Yet despite the intense media frenzy, or excitement, about the seemingly very near prospect of human cloning, the advances made by Dolly’s research team have not led to a world filled with cloned humans, let alone the great increase in cloning that was predicted.
[00:11:35] Why not, you might ask.
[00:11:37] Well, although scientists believe it could theoretically be possible, it would be inadvisable, and there simply isn’t the will to try it.
[00:11:46] It doesn’t mean that there haven’t been some developments though.
[00:11:50] Indeed, a human embryonic clone was successfully created in 2013 using DNA from skin cells, and two monkeys were successfully cloned in China in 2018, using the same technique as for Dolly.
[00:12:06] This suggests that the same technique that created Dolly the Sheep could potentially be used in humans.
[00:12:13] But human cloning was and still is considered to be too dangerous and completely unethical.
[00:12:22] Approximately 46 countries have banned human cloning, although some of these countries still allow human embryo cloning for research purposes despite bans on human reproductive cloning.
[00:12:35] There seems to be a general consensus, an agreement, that attempting to create a human clone, also known as reproductive cloning, is unacceptable. However, in the USA, despite powerful anti-cloning religious influences, there are actually no laws regulating human cloning at a federal level.
[00:12:59] In the UK, reproductive cloning is banned. Therapeutic cloning, cloning human embryos to research the development of genetic diseases, and embryonic cloning for stem cell research, are both allowed but highly regulated.
[00:13:15] At the UN and in the European Union, there is no clear consensus on creating fully binding laws that ban cloning. Some European countries allow cloning for therapeutic and stem cell research, as do many countries in Asia.
[00:13:32] It seems that the awkward questions about the creation of life that Dolly the Sheep has generated are still very far from being adequately resolved - both legally and ethically.
[00:13:45] This being said, Dolly’s creation and the process used have been invaluable to science.
[00:13:53] Indeed, the original purpose of creating Dolly was to help scientists to better understand and cure diseases in humans, not to clone them.
[00:14:04] The main benefit of Dolly’s creation has been the advances made in the field of cell research.
[00:14:11] Prior to, before, the creation of Dolly, scientists believed that once cells had become specialised they completely lost their ability to be able to be reprogrammed to produce other types of cells.
[00:14:26] What Dolly had proved was that cellular nuclear reprogramming is indeed possible - in other words that we can turn back time in terms of the development of specialised cells to reproduce stem cells from specialised ones.
[00:14:42] You’ve probably heard the term “stem cell” before, but here’s a quick explanation, which will help you understand why Dolly was so important.
[00:14:52] Stem cells are the very special type of cell that have the potential, the ability, to develop into many different types of cells. Stem cells can replicate, they can divide into exact copies of themselves, forming more cells, known as daughter cells.
[00:15:12] You can think of stem cells as being the very building blocks of life itself.
[00:15:18] They provide the raw materials required to produce all other types of cells in the body.
[00:15:24] Previously, research into stem cells required embryonic stem cells, cells from a human embryo, which understandably raises a huge amount of ethical concerns.
[00:15:37] When scientists clone human embryonic stem cells for use in the lab, there’s an argument that they are creating a human being, giving themselves God-like powers.
[00:15:49] Even if the embryos they are using are really only the starting point of life, a microscopically small bunch of cells, they could theoretically become humans like you and me.
[00:16:01] Understandably, not many people are comfortable with the idea of humans being created for research purposes.
[00:16:09] So here’s where the importance of Dolly comes in.
[00:16:13] The creation of Dolly showed that we can create artificial stem cells from adult cells using blood or skin tissue, without having to clone human embryos.
[00:16:26] This means that scientists can run experiments on these artificially created stem cells, helping us better understand diseases, without the same ethical dilemma of cloning human embryos.
[00:16:41] Indeed, this technology was used to create the genetically modified heart in the first pig-to-human heart transplant.
[00:16:50] As you can create these artificial stem cells using a patient's own cells, it is becoming increasingly possible to create more personalised treatments for diseases, as well as reducing the chances of rejection when growing organs for transplantation.
[00:17:08] Obviously, this is good news for medical science.
[00:17:12] But Dolly’s legacy expands further than just the medical world.
[00:17:17] Cloning animals has continued to develop as an industry.
[00:17:21] Particularly desirable farm animals are starting to be cloned, so that animals with valuable characteristics can continue to breed.
[00:17:31] This mainly takes place in China and the USA - the cloning of animals used for food has been banned in Europe.
[00:17:40] Some types of animals that are bordering on extinction have also been cloned to try to prevent them from dying out as a species.
[00:17:48] You may have heard tales about bringing back mammoths, or even dinosaurs, from the dead using cloning, just like they did to create Dolly.
[00:17:58] This is now more of a possibility than ever before, provided we have DNA that has been well preserved.
[00:18:06] While not quite as impressive as a T-Rex, scientists in America have already successfully cloned an endangered type of American ferret, a small furry mammal, using cells from a deceased, a dead, individual.
[00:18:22] In addition, there are also various companies around the world that specialise in the cloning of pets for wealthy owners, people whose favourite dog or cat has died and they are prepared to pay tens if not hundreds of thousands of dollars for a carbon copy of it.
[00:18:42] So, now we’ve discussed the importance of Dolly’s creation and its implications, what about the actual sheep herself?
[00:18:50] We’ve really skipped over our main character, haven’t we?
[00:18:54] Well, the reality is that, although Dolly’s existence was remarkable, her life itself was pretty unremarkable.
[00:19:04] She was a sheep, she got up in the morning, she ate grass, and did what every other sheep in the world does.
[00:19:11] Dolly lived with a flock of other sheep, some cloned, some non-cloned, and went on to have six lambs, all fathered naturally by the same ram, the male sheep.
[00:19:24] Unfortunately, Dolly developed arthritis - the disease that causes the joints to become swollen, causing pain and stiffness.
[00:19:33] Older sheep often suffer with arthritis, it’s not uncommon at all, however, Dolly was only middle-aged when she first started showing signs of stiffness.
[00:19:45] In 2003, her handlers noticed that she was coughing frequently. A scan revealed that she had a severe disease that causes lung cancer in sheep, again not uncommon at all.
[00:19:58] But she was old and unwell, and it was decided to put her to sleep, to euthanise her, while she was still unconscious during the scan.
[00:20:09] There were some fears that Dolly’s ill health, or sickness, could be linked to her being a clone, and that her arthritis could be linked to premature ageing.
[00:20:20] However, out of the other Dolly clones that were later made from the same cell culture, only one sheep appeared to develop moderate arthritis.
[00:20:30] So, it may well have just been bad luck.
[00:20:34] To conclude, Dolly the Sheep has inspired some of the most important recent developments in genetic modification and biotechnology.
[00:20:43] While the hype, the excitement, surrounding her creation and the fears that it produced have faded, the improvements in science that she directly inspired have been truly groundbreaking.
[00:20:56] Dolly the Sheep was living proof that adult cells could be reprogrammed to make stem cells.
[00:21:03] Thanks to the work of the team at the Roslin Institute, we are a step closer to understanding and ultimately curing some of the most serious and debilitating diseases.
[00:21:14] And, contrary to what the fear mongers might have said back in 1997, the world is not filled with human clones, dinosaurs are not roaming the streets of London and New York, and in fact all that happened was that a very unordinary sheep ended up living a very ordinary life.
[00:21:35] OK then, that is it for today's episode on Dolly the Sheep.
[00:21:41] I hope it’s been an interesting one, and that you’ve learned a little bit about the science behind cloning as well as some of the important advances that Dolly’s creation has inspired.
[00:21:51] As always, I would love to know what you thought about this episode.
[00:21:55] What are your thoughts on human cloning?
[00:21:57] Are there any circumstances in which you think it should be allowed, or should it be completely banned?
[00:22:03] What about animal cloning for agricultural or medical purposes?
[00:22:08] How do you think stem cell therapy could change our lives in the future?
[00:22:13] I would love to know, so let’s get this discussion started.
[00:22:16] You can head right into our community forum, which is at community.leonardoenglish.com and get chatting away to other curious minds.
[00:22:25] You've been listening to English Learning for Curious Minds, by Leonardo English.
[00:22:30] I'm Alastair Budge, you stay safe, and I'll catch you in the next episode.
[END OF EPISODE]
