Interview with Dr Neil Murray

About Dr Murray

The Interview

Further information

About Dr Neil Murray

Neil Murray was born in Sydney, NSW. He attended Brookvale Primary School and Manly Boys' High School. In his final year at school, Neil studied English, French, Mathematics I and II, Physics and Chemistry.

At the University of Sydney, Neil gained a BSc (Hons), majoring in Zoology and Botany. Then, in the Botany Department of the University of Sydney, Neil completed his PhD, studying the "Ecological genetics of Insects".

Neil has worked at LaTrobe University since completing his PhD, but he has enjoyed study leave appointments at

University of Liverpool, United Kingdom, in the Department of Genetics
University of British Columbia, Vancouver, Canada, in the Institute of Animal Resource Ecology

Neil is currently a Senior Lecturer in the School of Genetics and Human Variation at La Trobe University. Neil is also the Director of the Centre for Conservation Genetics.
In 1997, the Schools of Biochemistry and Genetics at La Trobe have amalgamated to become The Division of Biochemistry and Genetics.

Neil's wife, Heather is currently studying for a PhD in women's health at Melbourne University. Heather and Neil have three school age children, in years 2, 4 and 7 in 1997.

For relaxation, Neil enjoys camping, walking, literature, theatre, and all sorts of music. In the past Neil has been involved in Morris dancing, but he says that he now spends so much time 'running around with the children' that he has given up his dancing.

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The Interview with Dr Neil Murray

The topic Dr Murray chose to discuss was:

Use of DNA fingerprinting to study relationships between populations of Eastern Barred Bandicoots

Interviewer: What is the main purpose of your research or the genetic technique you use?

Dr Murray: We have used DNA fingerprinting to study the similarities and differences between populations of Eastern Barred Bandicoots in Western Victoria and Tasmania. The information we obtained from this study is used in making decisions about the management of these animals in the present and in the future.

Interviewer: Can you describe briefly how you are doing whatever you do?

Dr Murray: We analyse both nuclear and mitochondrial DNA from the Eastern Barred Bandicoots to measure the variation between individuals and populations. We digest the DNA with restriction enzymes and use electrophoresis to separate the fragments formed. DNA probes and Southern blotting enable us to view the bands of interest to our study.

Interviewer: Who or what (animal or plant) will benefit from your research/techniques?

Dr Murray: The separate populations of Eastern Barred Bandicoots in Victoria and Tasmania will benefit from this work. Eastern Barred Bandicoots are a threatened species in Victoria, so it was important to know how best to manage the breeding of the individuals we have remaining. The organisms that make up the communities of which the Eastern Barred Bandicoots are members will also benefit, as disruption of the population of one species in a community has a flow-on effect to other species in the same community.

Interviewer: What are the economic implications of your applied genetics? (How expensive is it to do? What will be'are the cost benefits of the outcome?)

Dr Murray: The initial research cost about $30 000 for the scientist who did the laboratory work. That was Nick Robinson, and this was the project he worked on for his PhD. (Dr Robinson is now working at the Victorian Institute of Animal Science, looking at DNA from sheep and ostriches.) Other costs in this project were incurred in Nick's supervision, and in dealings with various Government Departments. The money is well spent, I believe, since results such as this enable better targetting of conservation dollars to genuinely threatened species.

Interviewer: Historically, what is the scientific background to the research you are now doing?

Dr Murray: Before the 1970s, the attitude to wildlife was pretty much to leave it alone and let it look after itself. Zoos often started with one breeding pair of a species, and from them, the entire zoo population developed. No-one considered the consequences of the extensive inbreeding that occurred in these captive populations, even when the animals became noticeably poorer at survival.

In the 1970s it was realised that inbreeding and loss of variation were endangering processes for the long term survival of wildlife. This was true amongst both captive populations and wild populations of animals which were increasingly becoming isolated due to habitat destruction. It was recognised that care needed to be taken with breeding to reverse this process, but how could relationships between individuals be identified?

Initially, techniques of protein analysis were used to measure differences between and within populations, but the availability of DNA techniques, which are much more sensitive, has made work such as ours possible.

Interviewer: For a Year 12 Biology student to understand what you are doing, some background knowledge of biological concepts will be needed. Can you tell me what biology is relevant to what you are doing, and why?

Dr Murray: At the level of populations of Eastern Barred Bandicoots, students need to have an understanding of the principles of population genetics. In the case of the Eastern Barred Bandicoot, we were interested in measuring the extent of similarity and difference in the gene pools in the populations of Eastern Barred Bandicoot in Victoria and Tasmania. Even now, we do not know whether these are one species, or if they should be classified as sub-species. This has important implications for the management of the severely endangered Victorian Eastern Barred Bandicoots.

At the molecular level, students need to understand the biology of DNA, how the nucleotide sequence is transcribed onto mRNA and how mRNA is translated into proteins at the ribosome. All of this is needed to understand how small differences in the DNA, that is mutations accumulated over time, can lead to variations in the Eastern Barred Bandicoots alleles, and variability in the species' gene pool. It is this variability in the gene pool that, in nature, enables species survival in the face of variation in environment. This, of course, is Natural Selection.

Once a population becomes very small, as in the case of the reproductively isolated endangered, Victorian Eastern Barred Bandicoots, the variability in the gene pool is reduced. This is sometimes described as a genetic bottleneck effect or random genetic drift.

The few surviving Eastern Barred Bandicoots interbreed amongst themselves, but the resulting population is severely inbred, with a reduced chance of survival in the face of environmental change. The current drought is such a change, and we suspect that it is hitting the Victorian Eastern Barred Bandicoot population very hard.

So it becomes important to be able to measure the DNA similarities and differences in the Eastern Barred Bandicoot populations so that we can draw conclusions about the animals' gene pools. With this information, the State and Federal Conservation authorities can make decisions about how best to manage the Eastern Barred Bandicoot.

Since we have examined both the nuclear DNA (nDNA) and the mitochondrial DNA(mtDNA) of the Eastern Barred Bandicoot, students need to be aware of the differences in mutation rate and evolutionary rate between these two types of DNA.

Nuclear DNA, the DNA in the nuclei of all the animal's cells, is passed from generation to generation via the gametes of the parents. Students need to understand how gametes are produced by the process of meiosis, and how this process leads to assortment of the chromosomes as well as shuffling of the genes during chromosome crossover. This means that nDNA is constantly being redistributed and rearranged in each generation. It can still tell us much about maternal and paternal relationships in a population.

Mitochondrial DNA, on the other hand, is helpful for different reasons. As students would know, the animal sperm is a small, actively swimming cell. It has mitochondria to provide the energy for the movement of the flagella, but these are not transferred to the ovum at fertilisation. All that the ovum gets from the sperm is the haploid set of chromosomes that will form half of the zygote's nDNA. On the other hand, the large ovum has mitochondria and all the other cellular organelles. So the mitochondria of every individual are inherited from the ovum, that is, maternally. But mitochondria reproduce by a process similar to mitosis, so their DNA is not subject to the possibilities for rearrangement which meiosis gives to nDNA. The result is that mtDNA is a much more stable molecule, with random mutations accumulating slowly over many generations then being passed to all future generations of mitochondria. For this reason, mtDNA can give us important information about the evolutionary distance between the mainland and Tasmanian Eastern Barred Bandicoot populations. By measuring the number of mtDNA differences between the populations, and knowing the rate of accumulation of such mutations, we were able to estimate that it has been approximately 10⁶ years since the mitochondrial genomes separated. So even though Victoria and Tasmania were connedted 10 000 years ago, during the last ice age, the gene pools of the two remaining populations of Eastern Barred Bandicoots must have been separate throughout that period.

Interviewer: I now need to know something of the techniques used in your research. Can you tell me what techniques are important, and why they are important?

Dr Murray: Let's start with a flow chart which describes the steps taken from the animals to the analysis of the DNA.

The Eastern Barred Bandicoot is humanely trapped
(I would have put a lovely picture of an Eastern Barred Bandicoot here,
but the owner of the photo has concerns about the issue of copyright.)
You can look at the picture at Dept. Environment and Land Management in Tasmania.
Click back arrow to return here.

Take 1 mL of blood from a vein in the ear.
(Recently, improved techniques have made it possible to use fur as the sample source.
We are able to use PCR to amplify the DNA from fur and so avoid taking blood from the animals.)

Isolate the white blood cells and extract the total DNA
(Both nDNA and mtDNA are extracted)

Digest the DNA mixture with a range of restriction enzymes

Run the DNA on an electrophoresis gel
(This separates the fragments by size)

Transfer the bands of DNA from the gel to a nylon membrane
(This is known as Southern Blotting)

Immerse the nylon sheet in a bath with radioactive oligonucleotide probes.

Examine the bands of interest.

As you can see, the methods up to the isolation of the DNA mixture are just standard laboratory procedures used routinely in many laboratories. It is not until we begin to manipulate the DNA that we are using the modern techniques of biotechnology.

Once we have isolated the DNA mixture we divide it up into several 'lots', since we use several different restriction enzymes to digest it. As you know, different restriction enzymes cut the DNA at different nucleotide base sequences, so we essentially repeat the same experiment many times, each time with a different restriction enzyme. We can then compare the various band patterns we obtain and gain more useful information by these comparisons.

Once we have the DNA bands blotted onto the nylon membrane we need to isolate the nDNA bands or the mtDNA bands we are interested in. To do this, we use oligonucleotide probes, but the nature of these is different depending on whether we are looking for nDNA or mtDNA.

To probe for nDNA we use probes known as minisatellites. These oligonucleotides make use of the fact that all nDNA contains tandemly (=next to each other) repeated sequences of bases. Different alleles contain differing numbers of these repeats. A minisatellite is constructed so that it contains 13 -19 nucleotides which are complementary to and so bind specifically to the tandem repeats in the nDNA. The minisatellite can be constructed with radioactive phosphorus in it so that it is visible upon X-ray. So we can treat the bands of DNA on the membrane to separate the nDNA double strands, then soak the nylon membrane in a solution containing the minisatellite. The minisatellite DNA will bind with its specific tandem repeats and we can use X-rays to see where that has occurred on the membrane. Comparison of bands from different Eastern Barred Bandicoots will let us see how closely related, or not, they are. In fact, we can quantify the differences between fingerprints and from nDNA we were able to identify and compare a single gene locus. This part of the work was particularly useful in establishing parentage of the various Eastern Barred Bandicoots in captive populations.

The probing of the mtDNA is similar in theory, but a different type of probe is needed. For this, we needed to use a probe made from the mitochondrial DNA of a marsupial mouse. As you know, Australia's marsupials are believed to be quite closely related in the evolutionary sense, and we have found that there is enough similarity between marsupial mouse mtDNA and that from Eastern Barred Bandicoots to make sections of the mouse mtDNA useful probes. So this is what we used in our investigation of the Eastern Barred Bandicoot mtDNA. The details of the technique are similar to what we did for the nDNA. As explained earlier, this mtDNA analysis was used to establish genetic similarities and differences within and especially between Eastern Barred Bandicoot populations.

Interviewer: What do you see as the major biological implications of the work you are doing? For example; Are genotypes or phenotypes being altered? Is a species survival potential increased? Will someone or something have a better quality of life?

Dr Murray: With the information we now have about the relationships within and between the Eastern Barred Bandicoot populations, the management of this species can be carried out in such a way that the Eastern Barred Bandicoot has the best possible chance of survival in each of its ranges. With continuing monitoring of the genetic variability it should be possible to maximise this to give the Eastern Barred Bandicoot the maximum chance of survival in the face of environmental changes such as climate chance, including the greenhouse effect, the introduction of new diseases or right now, drought.

Captive breeding programmes and planned releases back into the wild are currently underway in Victoria, with mixed results. The major environmental threat, apart from habitat destruction for farming in western Victoria, are foxes. It's no use releasing Eastern Barred Bandicoots back into the wild unless they can be protected from this very active introduced predator. (Interestingly, there are no foxes in Tasmania, and the Eastern Barred Bandicoot population there, although threatened, is not in nearly as much trouble as is that in Victoria.)

Our results are also useful in the captive breeding programmes, where it is now possible to minimise inbreeding and maximise genetic variability, again helping avoid extinction.

Interviewer: There is often discussion or debate about issues associated with biotechnology. What is one such issue relating to your work? Can you outline the arguments of the opposing sides of the debate please?

Dr Murray: Three major issues come to mind:

ISSUE	Arguments for:	arguments against:
Is it ethical to trap wild animals and take blood or other tissue samples from them?	Yes. If this increases the potential survival of a species or population by the knowledge gained from such a practice. (This is the view that animal conservationists would take.)	No. Species that are going extinct should be allowed to go extinct without interference by humans. (This is the view that some animal rights people would take.)
Is it worth spending a great deal of money to save the Victorian Eastern Barred Bandicoot population?	Yes. It has been shown by the mtDNA investigation that the Victorian Eastern Barred Bandicoot population is sufficiently genetically different from the Tasmanian population that they might actually be different subspecies. Each population is probably adapted to its own environment.	No. "If you've seen one bandicoot, you've seen them all!" There are so many endangered species and populations it's impossible to save all of them. The limited money available would be better spent on conserving larger less threatened species so that they don't become endangered.
Is the way we classify animals and plants into species and subspecies distorting the way we target the money spent on conservation?	Very genetically distinct populations are not always recognisable phenotypically as significantly different and are therefore classified as one species. (This is currently true for the Eastern Barred Bandicoot.) Long term conservation and survival of the species may need all that genetic variability to survive environmental changes. Both the Victorian and the Tasmanian Eastern Barred Bandicoots may be necessary for the survival of the species. So the Victorian Eastern Barred Bandicoots must be protected.	As long as you've got some Eastern Barred Bandicoots it doesn't matter where they came from. It's not worth spending money on the endangered Victorian Eastern Barred Bandicoots when there's not much problem in the Tasmanian Eastern Barred Bandicoot population.

(Author's note: Whilst discussing this topic with Dr Murray, I became curious about the status of the Victorian and Tasmanian Eastern Barred Bandicoot populations as one or more species. I asked him if the experiment to check for ability to interbreed had been done. The answer was a wry smile and 'no'. It seems that there is some debate as to the desirability of such an experiment. The 'purists' say that the populations have been separated for so long it would be wrong to try to breed them, even for scientific purposes. The 'curious' are keen to know what would happen. Dr Murray favours putting a few from Victoria and a few from Tasmania on an island somewhere in Bass Strait and letting them sort it out. What do you think?)

Interviewer: Can you suggest some reading material relevant to anything we have discussed about your work, its implications and issues associated with it?

Dr Murray: Many of the conservation issues I have touched on are discussed in more general terms in the textbook "Principles of Conservation Biology", Gary Meffe and C.Ronald Carroll, 1994, Publ; Sinauer, Sunderland, Mass.

Graeme O'Neill wrote a couple of articles on this work a while ago when he worked at The Age, I don't know how easy it would be for students to track these down, but their titles are:

"The bandicoot leaps back from the brink (400 bandicoots now thriving and breeding in three separate locations in Victoria)." G.O'Neill, The Age, 28 April 1993, page 3.
"The tip's down-and-outers are a superior breed" G.O'Neill, The Age, 9 July 1991, page 5.

The recovery Outline for the mainland Eastern Barred Bandicoot can be found on the Internet at the Australian Conservation Authority site.

Another extremely useful Internet site is the Eastern Barred Bandicoot Bibliography, out of Deakin University.

A search of the Internet using Alta Vista, and entering "eastern barred bandicoot" brought up about 60 hits, at least some of which would be useful to students.

Interviewer: Thank you for your time.

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Further information relevant to Dr Murray's work

You can read more about the work of Dr Murray, by clicking here.

For ideas on where you might find additional resource material, look again at the section Resources on another page at this site. And don't forget the power of the Internet to provide you with information. A well thought out search, using a search engine such as Alta Vista, should provide more information than you can possibly use!

Please do not phone Dr Murray for further information for your CAT. He, like the rest of the staff in Genetics, is a busy person. However, if you think we can help you some more, use either the comment form or the email address for this site and we will do what we can.

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This page is maintained by Jenny Herington, who can be contacted at bio_cat@bioserve.latrobe.edu.au by email. All of the pages at the VCE Biology Students' site are copyright © Biochemistry, LaTrobe University. Last update :1 September 1997