People of Science with Brian Cox – Dame Ottoline Leyser on Barbara McClintock


Brian: So could you describe who you are and what you do. Yes. My name’s Ottoline Leyser and I’m a Plant Developmental Geneticist. I work in a research institute in Cambridge it’s called The Sainsbury Laboratory and the goal of our institute is to try to understand how plants control their growth and development. Brian: Who have you chosen as your person of science. Ottoline: So my person of science is Barbara McClintock. Brian: Now her work is clearly important. I mean she got the Nobel Prize in 1983 but could you outline how important it is in your area of study? Ottoline: There are two major discoveries that she made. One of them was to provide definitive proof that genes were on chromosomes. Brian: So genes are an abstract idea. So we say that you know blue eyes and brown eyes and those characteristics. Ottoline: That word was coined as, absolutely, an abstract idea to describe a hereditary unit, some kind of thing that passed from generation to generation. But what is it gene physically? And the chromosome theory was the sort of beginnings of trying to understand what a gene was and what came out of that was that genes were somehow, somehow on or part of these chromosomes. And then what Barbara did was really provide direct evidence that that was the case. Brian: I find it just baffling actually because you are talking about someone looking physically down a microscope and physically seeing things move around and saying that correlates with this property. And why did she work with maize, that’s corn? Ottoline: It’s a beautiful genetic system, the genetics you can do it in maize is very powerful. From her point of view it’s partly because the chromosomes are big and so you can see them more easily down a regular microscope. Brian: She was obviously very eminent early on and then makes this what turned out to be a radical breakthrough. Ottoline: She developed over a number of years a substantial body of evidence that showed that genes could move that they can jump about the genome. And in moving around they quite often cause the chromosomes to break. So she developed this concept of ‘jumping genes’ or ‘transposable elements’ and has certainly changed the way we think about genomes. Brian: And we have a flower here which is an example of that process in action. So how are we to understand those colours in the context of Barbara McClintock’s work? Ottoline: So these roses are a very beautiful and graphic illustration of this idea of ‘jumping genes’. So the reason that they have two colours is because in the cells of these petals there is a gene that allows the cells to make the red pigment. And if there’s a ‘jumping gene’, these transposons stuck in that gene it doesn’t work. So you get white. Brian: So this transposon that’s just genetic material that’s got in there randomly essentially in the sequence and it just breaks it, doesn’t work. Ottoline: When it jumps out then you can stick the gene back together again and that restores the red function and so you get patches of red. Brian: The research was not taken seriously at first was it because it was considered so radical. Ottoline: It took a while. The ideas she was proposing was so radical the broader implications across biology for that did indeed take quite a long time to find its place. Brian: So in a sense what had to happen was that the consensus or I suppose just knowledge in a way had to catch up with the research that she’d done. And so she withdrew didn’t she, to some extent? Ottoline: Yes absolutely. I think she felt people weren’t getting it. So why should she keep talking about it? But eventually she did indeed get the recognition she deserved in the form of the Nobel Prize for Medicine and Physiology as the sole winner. Brian: It is rare isn’t it for just one person to get the Nobel Prize. She is essentially laying the foundations for a whole field. The field. It’s a remarkable thing. Ottoline: And it was a really radical idea. She decided that the way it works is very, very different from the way other people were thinking so she definitely had to take a big kind of step into the unknown. I think it is indicative of her determination just to do the good work and find out what was going on rather than to worry about what other people thought about it. And I think that’s another reason why I find her inspiring.