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We are what our grandmothers ate

Professor Susan ClarkProfessor Susan Clark

3 September 2009

A pioneer in the emerging field of epigenetics reveals how high school biology led her to investigate why genes do what they do.

Working with identical twins, NHMRC Principal Research Fellow at Sydney’s Garvan Institute of Medical Research, Professor Susan Clark and her team found that ‘we are what our grandmother ate’. Here she explains to Dr Andi Horvath what this means in genetic terms and recommends subjects that could be studied by highschool students interested in pursuing a career in biology.

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Transcript of podcast

Voice-over: Welcome to this National Health and Medical Research Council podcast. Every year NHMRC celebrates ten of Australia’s best health and medical research projects. In this interview series we explore the job, the person and the event that led to a career in medical research.

Interviewer:  I’m Dr Andi Horvath. Come with me and meet these Chief Investigators of medical research projects. Let’s ring Professor Susan Clark. She’s an NH&MRC Research Fellow at Sydney’s Garvan Institute of Medical Research. I hope she’s in her office.

Prof Susan Clark: Hello, Professor Susan Clark speaking.

Interviewer: Professor Susan Clark thanks for talking to us. Can you tell us a little bit about what you do, like what do you say to people at a bus stop who ask what you do?

Prof Susan Clark: First of all I say I’m a scientist. I work on people’s genes and I’m trying to understand what makes people different at their gene level. And so to do this we work on identical twins and when you look at them the twins look similar but there’s always differences. And so this is really intriguing because identical twins have the same genetic make-up and yet there are differences and that’s what our work is about, is to try and understand what leads to changes in their susceptibility to different diseases. This is a field that is called epigenetics. It’s a field where we believe the environment can have an impact on how the genes are interpreted.

Interviewer: Right, so this information about the environment especially when you’re growing and you’re young, is important to what might happen to you later on in life in terms of your health?

Prof Susan Clark: That’s right, so in particular we know that what we eat makes a big difference on our health, but how that impacts on the genotype is what we’re trying to understand.

Interviewer: Ah got it.

Prof Susan Clark: So there’s a classic phrase that we often use is that, ‘we are what our grandmother ate’.

Interviewer: Really!

Prof Susan Clark: Yep, so it’s very much what, well actually our grandmother, our germ cells which are sort of the cells which make the baby, are growing inside her, it’s actually changes that happen there, the diet that she has that impacts on the grandchildren.

Interviewer: Of course, because the environment would effect the genes.

Prof Susan Clark: That’s right, and so we’re becoming more and more aware it’s not just diet it’s also exposure to environmental impacts like smoking or toxic sprays.

Interviewer: So what sort of things do you do day-to-day, what does a Chief Investigator get up to?

Prof Susan Clark: Well I’m sort of I’m in the control tower if you like and I have a wonderful time asking questions. I look at new reports, discoveries in the literature, and I look at how we can design experiments to actually take the next step. I’ll come up with ideas to test and then I’ll go into my lab and I have a team of twenty odd scientists, from students to PhDs, and we sit down and we talk about how we’re going to address the next scientific question.

Interviewer: So how did it all start for you Professor Susan, how did you get interested in your field?

Prof Susan Clark: Well I was very much someone who loved science. I loved discovering. In particular I think I liked botany – that’s where I started at school. We used to do experiments on growing seeds in cotton wool and looking at different temperatures and how the plants grew and I thought that was fascinating.

Interviewer: So you followed that biology bent. What sort of things do you recommend for people to study these days if they’ve also got a biology bent?

Prof Susan Clark: Well I think in high school it’s really important to get abreast of the sciences, so you know you do need chemistry, you need physics and you need mathematics because they all impinge on how we interpret biology. So biology is an interaction between the chemical structures, the physical forces and we need the math to be able to understand how they all interact together.

Interviewer: And what’s the most exciting part of your job? Do you ever have moments where you go, ‘wow that was a really good day’, or, ‘I remember when this happened in the laboratory and the data came to my desk’? Tell us about those moments.

Prof Susan Clark: I think these moments actually happen quite often. I mean, I come home and I talk at the dinner table about, ‘what did you do mum?’ and I tell the kids. And it’s really every day that you find that you make a hypothesis about how you think something’s going to work, and then you see a piece of data that actually fits that hypothesis and you’re going, ‘wow this is what I think is happening’, and then you know you get that piece in the puzzle. And every day the jigsaw puzzle, if you like, gets filled in more and more and that’s a very exciting feeling.

Interviewer: One of the questions I’ve been asking researchers is, what would they be if they weren’t a medical researcher? Can I take a stab Susan, that you might be perhaps a botanical researcher?

Prof Susan Clark: (laughter) Actually I’d be a cook.

Interviewer: Really!

Prof Susan Clark: I love cooking too but it’s exactly the same really. Cooking where you get to experiment with different ingredients and put them altogether. At least being a cook you get to eat your discoveries I suppose. No, I think cooking would be what I’d do rather than science, but hmm.

Interviewer: Well, that’s interesting.

Prof Susan Clark: There we go.

Interviewer: Professor Susan Clark thank you so much for talking to us it’s been very interesting meeting you.

Voice-over: This podcast was brought to you by the National Health and Medical Research Council, working to build a healthy Australia. You’ll find more information about this and other Health and Medical Research issues on our website at

Page reviewed: 8 April, 2011