JP: Its worth saying just how unexpected this scientific breakthrough was. There had been some success in the 1960s cloning frogs but it had become accepted wisdom that it was impossible to clone mammals, mainly because the experiments on mice had not led to any real success. So the Edinburgh scientists' achievement in cloning a sheep is immense.
The cloning of Dolly involved taking the nucleus from a sheep's udder cell and transplanting this into a sheep's egg with its own nucleus removed. The significance of this is that the nucleus is the cell's control centre. It contains the genes, made out of DNA, which provide the instructions for what goes on in the cell. Normally the genes which guide a fertilised egg's development into an animal are donated by both the mother and the father. But in Dolly's case they came solely from this original udder cell.
There are still many problems with the technique. It is very hit and miss. Out of 277 attempts to produce a cloned sheep, only Dolly was developed successfully. So they need to do a lot to improve the efficiency. And it has only been done with sheep so far we still don't know if it's possible in other animals, though the Edinburgh team say they aim to have cloned a cow by the end of the year.
JP: The main immediate benefit of cloning is that it could be used to create animal 'pharmaceutical factories'. This would be achieved by creating so called 'transgenic sheep'. Dolly is a clone but she is not transgenic her genes are 100 percent sheep. It should be possible to introduce important human genes into sheep cells before they are used to clone a sheep. For example, the group that cloned Dolly are hoping to introduce the gene that is missing in people with cystic fibrosis. They can even introduce it in a way that means the human protein it produces will be secreted into the milk. So simply by milking the sheep one could get large quantities of the protein that can then be used to treat the disease.
Another important protein that could be produced in this way is the blood clotting factor that is missing in haemophiliacs. It could also be possible to remove certain genes. If it proves possible to clone cows one could genetically manipulate certain cows so that their milk does not contain a protein that doctors believe could cause the majority of cow's milk allergies.
These enormous potential benefits of cloning have been ignored by much of the media who seem more concerned with creating horror stories about scientists creating a Frankenstein's monster or cloning Adolf Hitler. The Sunday Times even ran an article claiming that a Belgian infertility clinic had already created a 'human clone' accidently! This turned out to be complete nonsense just a straight case of identical twins, which, after all, are natural clones.
We still don't even know if it would be possible to clone a human being. The idea that some mad scientist would be able to clone lots of identical Hitlers ignores the fact that it is not simply your genes but also your environment that forms you as an individual. Someone who had the same genetic make up as Hitler could have turned out a pacifist given quite different circumstances in their life. Also the Nazis were a lot more than just Hitler they were a mass movement of the middle classes who couldn't have come to power without significant backing from big business and the fact that the left failed to stop them.
There is another problem with this sort of alarmism. It assumes that there are mad scientists out there who would have an interest in cloning human beings. But all the scientists I know who work in sensitive areas such as this only want to benefit humankind.
Also you cannot do research of this kind without significant amounts of funds. This is where the question of adequate public funding of science becomes especially important. The team that cloned Dolly were getting half of their funding from public money and half from a pharmaceutical company. But since they announced their discovery the government has said it is to stop their funding. This means that their future research will be purely for private enterprise. This will affect the sort of applications to which the discovery is put and how it is used.
It is also true that privately funded research is much less open to public scrutiny. You only have to look at the situation in the US where the attacks on abortion rights have fed into embryo research and it is now impossible to do any work on human embryos in the public domain. This has pushed such research into the private sector which is much harder to regulate.
The fact is we cannot separate potential abuses of scientific discoveries from what is going on in society as a whole. In Nazi Germany there were horrific 'experiments' carried out on people. Certain pharmaceutical companies that carried out this work are still making profits today. The only way of making sure such things never happen again is by stopping the Nazis getting to power.
JP: This discovery goes a lot further than the cloning itself. The fact that we can now reverse the 'programming' of the cells of the body could be of major medical importance. It is difficult to say too much without over-speculating but there are a number of potential applications.
One is the treatment of cancer. We know that cancer occurs when cells lose their normal programming and start growing out of control. So by understanding the process whereby you can artificially reverse a normal cell's signals this should also help us understand more about how cancers develop.
A very exciting potential application would be in creating a stock of reserve human tissue, say of bone marrow, for transplants, or skin tissue for burn victims, all taken from a person's own body. This would get around the problem we now have where a person's immune system often rejects a donor transplant.
It's also possible that further work of this kind could lead to some more far out possibilities. For instance, would it be possible to reprogramme the body to regenerate a limb? Or could we slow down aging? The possibilities depend so much on how research progresses over the next few decades.
JP: It's linked to a fantastic growth over the last decade in our knowledge of how a cell goes through its life cycle. It's useful to compare such a cycle to that of an oak tree. Everyone knows that an acorn grows into an oak and then the oak gives rise to acorns, and so on. So there is a cycle of life. We now know that every living cell also goes through a cycle. This involves the cell first duplicating its contents, including its genes, and then splitting into two new identical cells, which each receive an equal quota of the duplicated contents. The cycle is now ready to begin again. The major scientific advance is that we now know the essentials of what goes on in this cycle, even down to the molecules in the cell that regulate it. The Edinburgh group used this knowledge. They realised that it might be important to synchronise the egg and the transplanted nucleus so that both were at the same position in the cell cycle. That's what they did, and Dolly was the result.
JP: It was unfortunate that a lot of the early work was done in mice. One of the factors that seems to be different in mice is that it's very difficult to synchronise their cells. Also, the development of the mouse embryo follows quite a different pattern to that of a sheep. In particular the DNA instructions get 'read' a lot sooner than in sheep embryos. What may be happening in sheep is that because the process takes longer to get going it gives the transplanted nucleus more time to adapt to its new surroundings.
There's already some evidence that cows have similar characteristics that may also make them possible to clone. We'll have to wait and see about this, and even more so for other species.
JP: This work is incredibly important from a scientific point of view. It shows that an ordinary cell in the body contains all the information necessary to make a complete new animal. This is fascinating given that the different types of cells in the body are incredibly specialised. So brain cells behave one way, liver cells in a very different way, and this is because they produce very different sorts of proteins which are the building blocks of cells. Now everyone thought that this sort of specialisation was irreversible, due to irreversible changes in the DNA. The successful cloning of Dolly from an udder cell shows that this is obviously not the case.
Another important consequence of this work is what it tells us about DNA itself. When DNA was first discovered it was referred to as the blueprint of the cell in a way that was quite misleading. The idea grew that cells carried out the DNA instructions in a completely passive way. This fed into the notion of the 'selfish gene' that we are just what our genes make us. This discovery shows that it is not simply the DNA instructions that matter but also the cell environment that the DNA is in that makes a massive difference.
The problem is that the more science throws up these amazing new technologies, the more capitalism seems unable to make proper use of them. Today ordinary people do not have much control over scientific research and they do not have enough information. I think we need much greater public funding of science and greater awareness, but ultimately it's only in a different sort of society that discoveries like cloning will realise their amazing potential.