A talk by Professor Steve Jones on Evolution.

This evening's talk by Steve Jones at the Chester Literature Festival could have been a disaster. His talk was announced as 'Why evolution is right and creationism is wrong.' but the talk he thought he was about to give was on THE SINGLE HELIX which is the title of his most recent book (it has the picture of a snail shell on the front and flicking through my copy see that it is a large assortment of short scientific anecdotes - ideal dipping-in material. Just the sort of thing I like - and apparently snails are more than adequately represented (because snails are Professor Jones's speciality)). Apparently it was the third talk he had given in a matter of days but luckily he had both presentations with him.

'So which do you want?' he asked the audience, 'Creationism or The Single Helix?' A show of hands indicated the Creationism so he simply swapped his computers around and gave that talk instead. A true professional. It was almost a seamless transition. As a pretty seasoned giver of talks myself I was very impressed.

The talk was extremely interesting. I took six pages of notes. He started by setting the scene: more people believe in creationism than evolution, he said. This is a fact I find remarkable every time I hear it. According to the present incumbent of the White House 'The jury is still out.' on evolution.

He pointed out that although we share 98% of our genetic make-up with chimps this does not mean we are 98% chimp. We share 50% of our genetic make-up with bananas.

He ended this section of the talk with a few notable quotes:

'Scientists argue while believers do not.'

'Evolution is the grammar of biology' and is, according to Darwin 'descent with modification'.

Throughout the talk he referred to a family tree of languages. He described how it was possible to postulate the age of a common ancestral language - 60 000 years ago - by comparing words in the families of languages throughout the world and assuming constant rate of language change. The same thing can be done with family tree of a particular species but instead of looking at words it is necessary to look at the RNA or DNA and see how much that has changed. He used HIV as an example of a species because that has changed very quickly in the last few decades since it was first detected in the west in the early 1980s.

He illustrated how change happens in evolution by looking at the design of the most unlikely thing: the nozzle making detergent in a factory where his father worked in nearby Port Sunlight. The nozzle used to be a simple shape (like two cones joined together at their sharpest ends) but in order to improve it a series of these nozzles were changed in random ways - one made shorter, another longer, another with irregularities inside, for example - and each tried out to see which one worked the best. The best ones were then taken and reproduced - and then changed again. This process was repeated for 20 generations. The nozzle that resulted (i.e. the best nozzle) turned out to be a complicated thing; rather like the turned leg of a chair. It was a shape no one could have predicted and yet this was the shape that worked the best. That, says Steve Jones, is a model for evolution: it is 'dim but it works' - not an intelligent design at all.

HIV is thought to have changed using a similar process. He showed us a family tree for the disease. There were groups that were closely related or genetically similar - those that had evolved in the haemophiliacs that had disastrously been given contaminated blood; those who had had the disease passed onto them by their mothers; those unfortunate homosexuals who had been infected with disease during sex. Each of these families could be traced back to a common ancestor - a 'consensus' HIV with a postulated RNA. This postulated RNA was that was subsequently found to be close to the RNA sequence found in a clinic in the Democratic Republic of the Congo. It was from the preserved specimen of a patient that had died from unknown causes there in 1959; but had presumably been one of the first people to die from an HIV infection.

HIV is not an exclusively human disease. It can also occur in a variety of other animals including cats, chimps and seals. However the HIV in humans is genetically closest to the HIV in chimps and it is thought that it was first acquired from chimps - perhaps by a hunter being wounded by a chimp suffering from HIV.

However HIV is not fatal in chimps or other animals and this is due to evolution. Some people are also resistant to HIV - they can carry the virus for many years without becoming very ill; while other people, as we all know, die. It has been found that the resistant individuals carry many copies of a gene that makes a protein called CCL3L1. This protein shuts one of the doorways the HIV uses to enter a cell. The more copies there are of this gene presumably the more doorways can be closed. It has been found that some prostitutes in Africa have many copies of the gene and so they can continue working while infected and then infect their clients. Looking at the distribution of the number of copies of the gene in various populations it has been found that there are more copies (on average) in the African population than there are in the European population. This is because the African population has been living with HIV for a longer time. The people who do not have many copies of the gene have died once they have been infected; while those with copies have lived to have children. This is natural selection (and evolution) in action. The natural end result would be a population that consists of people who have many copies of the gene for CCL3L1.

However this will not happen, Professor Jones says, because we are human.

Because we are human we can speak, have an idea of consciousness and a sense of time, have religion, culture, education and science.

This has meant that we also have drugs; and these have stopped many of the deaths due to HIV - certainly in the western world.

In Africa however it is education that has prevented deaths. Education has encouraged people to have fewer sexual partners and also, presumably, to have protected sex.

Steve Jones ended the lecture by referring to something the last pope had said - that humans were chimps with a soul. Steve Jones said he wouldn't use the word 'soul' but he agrees we are different from the rest of the animal kingdom. Although we are spread all over the world we are, genetically, almost identical. The differences between us are negligible. Chimps living just a hundred miles apart show much more genetic variation. Furthermore, we have remained genetically similar for tens of thousands of years. Humans are different because we have changed the natural course of evolution. We have changed it through medicine and education; and we have education and medicine because we have language.

It seems to me that everything comes back to language. It is, as Professor Jones says, our unique response to the world. Maybe that, more than anything is our soul - which is an inspirational thought for any writer.