‘The platypus is a very unique creature: one of only several monotremes that exist in the world. Australia is very lucky to have it here. I’ve always been interested in Australian wildlife, so when I got offered a chance to do research for my Phd on the platypus, that’s when I decided to go into that field.
The core of my research was looking at genetic variation in platypus populations. It involved quite a lot of fieldwork. I was setting up nets in waterways around Victoria, trying to get a spread of the genetics we might find in south eastern Australia, while there was concurrent research going on in Tasmania that tied in quite nicely.
Initially, when looking for platypus suitable habitat you look for pristine environments. Then you start sampling in some not-so-pristine areas and realise you can catch platypus there. The main limitation for us, then, was the nets we were using, called fyke nets. You have to set them up in a stream you can wade into, so it has to be a shallow stream and only about three metres wide, so little creeks really, rather than rivers.
There are two types of DNA that I was looking at: neutral nuclear microsatellite markers and mitochondrial sequences. Mitochondrial DNA is something that is inherited maternally. You get it from your mother and it’s transferred pretty much identical – so what your mother had, you’ll have. You can trace back female descendants in that way.
Whereas the nuclear microsatellites – inherited half from your mum, half from your dad – shows a history from both sides. We were looking for mutual variation across microsatellites. It’s a hyper variable part of the genome, so looking at that can give you an idea of dispersal patterns or breeding patterns, so you can determine where different populations lie.
For example, we had a hypothesis that within a river basin if individuals are connected by waterways, they should be genetically similar, whereas individuals separated by land would be genetically distinct from each other. What we found, platypuses being semi-aquatic, was that they were moving over land to breed too, but this was a lot less common on the mainland compared to in Tasmania. We’re not as yet sure why this would be, but some of the theories relate to the conditions of Tasmania, such as more water, cooler conditions, less predation and reduced anthropomorphic modifications to environments. But these are just theories for now, so more research needs to be conducted.
It’s important to have lots of variation throughout the genome so that if any challenges are thrown at that population, like a disease for example, the population needs to be able to develop a resistance to that disease and there needs to be enough genetic variation there to develop that resistance. Also, if any changes in climate happen, some individuals might be advantaged in those new climate conditions. Others might be disadvantaged, but overall the population will be able to survive because you’ve got those genes which can adapt and do well in those conditions.
This research gives conservationists an indication of platypus genetic variation which will help future conservation projects. The important thing is looking at the breeding patterns or gene flows occurring, where individuals are migrating between because of their genetic similarities. For example, the King Island population had pretty much no genetic diversity at all, so this is clearly not ideal in terms of adapting to any changes in environmental conditions in the future.’
Elise Furlan’s thesis was titled: “Investigations of morphological and genetic variation in the platypus, Ornithorhynchus anatinus”.
* “My PhD” is an irregular series in which The Citizen speaks with recent Melbourne University PhD graduates.
