a story lives forever
Sign in
Form submission failed!

Stay signed in

Recover your password?
Form submission failed!

Web of Stories Ltd would like to keep you informed about our products and services.

Please tick here if you would like us to keep you informed about our products and services.

I have read and accepted the Terms & Conditions.

Please note: Your email and any private information provided at registration will not be passed on to other individuals or organisations without your specific approval.

Video URL

You must be registered to use this feature. Sign in or register.


Operons: JG Roth and JR Lawrence. Jacob and Monod


The process of transfer in bacteria
John Maynard Smith Scientist
Comments (0) Please sign in or register to add comments

I think it's important to distinguish two very different processes. The one that I and my colleagues have worked on mainly is a process called transformation, which only goes on in some kinds of bacteria. It does go on in both neisseria and streptococcus, which are the ones we're working with. This really does look like a highly evolved process for transferring bits of genes between closely related bacteria. You have really to be a pretty close relative before you can do it, and it's very common. Gonococcus, the organism that causes gonorrhoea, was shown by a young colleague of mine, Maria O'Rourke, to be essentially random mating. I mean, the amount of frequency of exchange of bits of DNA between gonococci is so frequent that their genes are in what we call linkage equilibrium, it's complete random assortment from what genes you have at different loci. It says something about not only their sexual habits but ours. Of course, you'll appreciate that recombination only matters if you've got gonococcus from two different sources, otherwise it's just having sex with yourself, and that doesn't have any...

[Q] So they constitute what you might call a gene pool, in a real sense?

That's right, that really do. But that's one kind of recombination. It's one I'm very interested in, because I'm interested in how did it evolve and so on. The other is a much more accidental thing. What happens is that there are these what are called bacteriophages, they're sort of viruses that live inside, say E. coli, as a disease. And they may destroy the E. coli. And when they destroy the E. coli they make a new protein coat, and they package their DNA in the protein coat and then they get into another bacterium. Occasionally they make a mistake, and instead of packaging their own DNA, they package E. coli DNA, and if that happens, then they carry E. coli DNA into whatever the next cell they attack is. And this is a much more accidental procedure, it's much less common. It transfers great big hunks of DNA sometimes. And the... the donor and the recipient don't even have to be particularly closely related for it to work. And both these processes are going on, and other ones as well, it's all very complicated.

[Q] So could you almost say that the chunks of DNA that are available to all the bacteria in the world constitute a kind of giant gene pool that they're constantly swapping in and out of combinations with each other?

Almost you can. And this was sort of the football team analogy, the idea of E. coli is that it just takes in DNA somewhere when it needs it. And it can buy it from a team in Germany if it wants to, you know, it doesn't have to stick to another English team. Indeed, this led some people... there's a... I think he's a Belgian microbiologist called Sonea to say that we really ought to think of the bacterial world as a sort of super-organism, and what was evolving is not the individual bacterial species but the organism as a whole. I have to say, I think this is complete nonsense, because it's, you know, evolution by natural selection requires that you have a population of things competing with one another, and you can't talk about natural selection operating on a single whole. But nevertheless, he was on to a point that there is this whole field of creatures which are exchanging genetic material.

The late British biologist John Maynard Smith (1920-2004) is famous for applying game theory to the study of natural selection. At Eton College, inspired by the work of old Etonian JBS Haldane, Maynard Smith developed an interest in Darwinian evolutionary theory and mathematics. Then he entered University College London (UCL) to study fruit fly genetics under Haldane. In 1973 Maynard Smith formalised a central concept in game theory called the evolutionarily stable strategy (ESS). His ideas, presented in books such as 'Evolution and the Theory of Games', were enormously influential and led to a more rigorous scientific analysis and understanding of interactions between living things.

Listeners: Richard Dawkins

Richard Dawkins was educated at Oxford University and has taught zoology at the universities of California and Oxford. He is a fellow of New College, Oxford and the Charles Simonyi Professor of the Public Understanding of Science at Oxford University. Dawkins is one of the leading thinkers in modern evolutionary biology. He is also one of the best read and most popular writers on the subject: his books about evolution and science include "The Selfish Gene", "The Extended Phenotype", "The Blind Watchmaker", "River Out of Eden", "Climbing Mount Improbable", and most recently, "Unweaving the Rainbow".

Tags: neisseria, streptococcus, Gonococcus, E. coli, Maria O'Rourke, Sorin Sonea

Duration: 3 minutes, 40 seconds

Date story recorded: April 1997

Date story went live: 24 January 2008