Sex, death and disease

Matt Hall – Biologist

Matt Hall is a lecturer in the School of Biological Sciences.

Sex, death and disease. If you were considering a career investigating the big three, what type of creature do you think you’d study?

While the obvious answer might be human beings, Matt Hall is delving into a whole other world of….water fleas. Matt describes them as “cute little transparent crustaceans that flick through fresh water”. They can be found in just about any fresh water puddle in the world – from deserts, to alpine regions, coastal ponds and even in lakes on campus at Monash in Clayton.

The correct name for the five-millimetre-sized water flea is Daphnia and it has been studied for over a hundred years because its “biology is perfect for understanding how and why animals evolve,” according to Matt, an evolutionary biologist.

Matt studies the biological challenges of ageing, fighting infection and mate choice. “Every organism faces the same challenge of finding a partner, fighting off pathogens and parasites and trying to live healthily – but why are some better at it than others?”

Daphnia are able to cope with all these challenges. They pack-in 30,000 genes into a small genome, they reproduce quickly, can create genetically identical daughters (known as clones), and will rapidly change and adapt to environments.

As a species the water fleas are the superheroes of the rock pool and can transform when they sense a predator is near. “They grow huge, ornate modifications – helmets and spikes – which makes them harder to eat and too big for a predator to pursue”.

“With the genomic revolution, you can reuse these creatures to revisit a lot of ecological and evolutionary questions using new technologies.”

Matt has returned from Switzerland to take-up a lectureship at the Monash School of Biological Sciences. “A lot of the work I do is about understanding what makes us all different.”

“We can either look at manipulating individual genes to see what happens but I am more interested in looking at a population, taking in all the variations, and working backwards to find genetic basis to traits. Using genomic tools we can assess why individuals and populations differ – how much is variation due to genetics, how are genes involved?”

So back to the water fleas….they are clonal but they also go through a cycle. Most of the year they produce clones (so the team can store them indefinitely – handy) but under poor conditions, they have sex and recombine – producing eggs that can survive drought or freezing, and can be revived hundreds of years later.

He is setting up a research group and his first family of water fleas are due to arrive from Europe. He has ordered a couple of hundred genotypes which will live in jars and await their fate.

We want to understand how health and ageing evolves – the mechanisms and genes involved – and to find the consistencies in relation to environment. In bad environments, individuals age much faster. Why? Is it the same process in different population or species? And when looking at disease, how does an organism fight infection while doing all the other things it needs to do?

So how does it relate to humans? “All the mechanisms are shared. When asking questions about disease and growing old, we share a lot of common architecture with the water flea.”

“Every organism faces the same challenge of finding a partner, fighting infectious disease and trying to live healthily – but why are some are better at it than others.”