Teachers notes – Professor Jenny Graves
Professor Jenny Graves was interviewed in 2000 for the Australian Academy of Science's '100 Years of Australian Science' project funded by the National Council for the Centenary of Federation. This project is part of the Interviews with Australian scientists program. By viewing the interviews in this series, or reading the transcripts and extracts, your students can begin to appreciate Australia's contribution to the growth of scientific knowledge.
The following summary of Graves's career sets the context for the extract chosen for these teachers notes. The extract highlights her interest in marsupial chromosomes. Use the focus questions that accompany the extract to promote discussion among your students.
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Funded by 100 Years of Australian Science
(National Council for the Centenary of Federation)
Summary of career
Jenny Graves was born in Adelaide, South Australia in 1941. She attended school in Adelaide Highgate Primary School then Presbyterian Girls' College (now Seymour College).
Graves received a BSc Hons from the University of Adelaide in 1964 and an MSc in 1967. Her research for these degrees involved the inactivation of the X chromosome in marsupials. She then received a Fulbright Travel Grant to go to the University of California, Berkeley to work with Professor Dan Mazia. She received a PhD in 1971 for her work on the control of DNA synthesis.
In 1971, Graves returned to Australia as a lecturer in genetics at La Trobe University. Her research interests focused again on marsupials and she became involved in gene mapping. Her current research involves investigating the organisation, function and evolution of mammalian sex chromosomes and sex determining genes. She is also interested in comparative genome mapping.
Graves became professor of genetics at La Trobe in 1991, and became a Fellow of the Australian Academy of Science in 1999. In 2001 she took a position at the Research School of Biological Sciences, Australian National University as head of the Comparative Genomics Research Unit.
Extract from interview
Looking to the local fauna: X inactivation in marsupials
Anyone who thinks of you in science, thinks of you in a marsupial context. Having had a marsupial start with David Hayman, when you came back from Berkeley with your PhD behind you how did you get involved in marsupials again?
Again that was completely by accident. When I went over to Berkeley I decided I was going to be a ‘proper’ molecular biologist and work on bacteriophages. But I had already been bitten by the bug of ‘Aren’t mammals fascinating?’ The work I had done with David Hayman was about X chromosome inactivation one X chromosome in females is actually genetically switched off and that was a fascinating saga. Another of my heroes, Mary Lyon, was the one who put forward the hypothesis in the early ’60s, and I was the one who tested it in marsupials. When I discovered that there is an inactive X in marsupials, I assumed it was just the same. It turns out that nothing is quite the same in marsupials.
When I came back to La Trobe University, Des Cooper an old friend of mine from Adelaide was a senior lecturer here. He was very keen to continue looking at X inactivation in marsupials, and we had to know what genes were on the X chromosome. He said, ‘Well, you’ve had all this experience fusing cells, and that’s one way we can map genes. How about doing some work on marsupials?’ I remember to my chagrin and embarrassment pulling myself up to my full height and explaining that I was not going to be ‘one of those Australians who end up working on "the local fauna"’. Only later did I see that there were good reasons for wanting to work on the local fauna. Just to keep Des quiet I made him a few hybrids, and that turned out to be so interesting that I continued some gene mapping work with marsupials. Gradually the realisation dawned that we had a goldmine there, that marsupials do things differently from placental mammals and that very often, if you compare those systems, you can figure out from how the two systems differ, what the ancestral system was like. So because of my interest in the regulation of genes and X chromosome activation, that became a very powerful way to look for variants.
When I first started, some people Jim Peacock, particularly said, ‘They’re going to be too different. You’ll never find out anything.’ When the first three genes I mapped were all exactly the same as in the mouse and the human, people started to say, ‘They’re all going to be the same so you won’t find out anything.’ But in fact they’re just right: marsupials are just far enough distant from mouse and man to be interesting and to provide us with variation, but they’re close enough to share the same control systems. Virtually everything I’ve done from then on has used comparisons between different groups of mammals, and most of it has turned out to be wonderfully interesting. I suppose I should have predicted that, but in the beginning I hadn’t seen the possibilities.
It’s interesting how long it has taken the rest of the world to wake up to the intellectual excitement of Australia’s isolation for 100 million years.
That’s quite true. When I first started getting interested in travelling and talking about my work which took me some time because I had young children if I mentioned a wallaroo, the audience would all fall off their chairs laughing. I became a bit of a comic turn, I think. I’d show lots of pictures of marsupials, and they’d all think, ‘Oh, this is such cute stuff.’ I don’t think they took it seriously until the saga of David Page’s ZFY gene: it pulled people up with a jolt to realise that marsupials could be a test of what should be truly conserved.
An edited transcript of the full interview can be found at http://www.science.org.au/scientists/jg.htm.
- What does Graves mean when she talks about fusing cells and making cell hybrids? Can you think of any applications of this kind of research?
- Graves mentions that marsupials are just far enough distant from mouse and man to be interesting. What kind of distance is she referring to and why is it interesting?
Select activities that are most appropriate for your lesson plan or add your own. You can also encourage students to identify key issues in the preceding extract and devise their own questions or topics for discussion.
- Work as a class and use the library and Internet resources to create a list of marsupials. Each student finds out more about one animal on the list and presents information about its biology, ecology and, if possible, its genetics. Create a summary table of the information on a whiteboard or a large sheet of paper.
- Graves mentions X chromosome inactivation, first proposed by Mary Lyon. Find out more about this hypothesis and how X-chromosome inactivation in marsupials is different. Write a paragraph on your findings.
Chromosomes and genetic mapping (Access Excellence, USA)
Students locate fictitious genes on a chromosome, using crossover frequencies. They then read an essay on sex chromosomes, and answer the questions that follow.
- The Eighth Floor, Tulsa Area Professional Development Consortium, USA
Mottled mosaic mice
Background information on sex determination, together with an activity that uses coin flipping to determine probability of the genotype of any particular cell.
The calico cat
Background information about the genetics of calico cats (calico cats have patches of colour, similar to tortoiseshell cats), together with an activity involving punnet squares.
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