Desert dreams, pet lizards and unravelling genomes with Mitzy Pepper

When Dr Mitzy Pepper knocked on a lecturer’s door as a student, she unlocked a whole new life path filled with quirk and colour.

Dr Mitzy Pepper is sitting at her desk in the Robertson Building. In the chilly Canberra winter, her computer screensaver – the red rocks and sand of a desert scene – is an ever-present reminder of her other office space.

Pepper studies lizards and her work takes her to the most remote areas of Australia. She has done species discovery work, deep dives into the genetic diversity of Australia’s lizards and explored the relationship between arid environments and the genetic history of its animal inhabitants.

“If you live in Australia, lizards are everywhere and I caught a lot of lizards when I was little,” Pepper says.

Her family pet Twinkle, a blue-tongue lizard, poses for the camera while Pepper speaks with ANU Reporter.

She says she encouraged her children to go with a reptile instead of a dog, as their winter hibernation means a less hands-on approach to pet ownership.

That’s not to say life with a lizard is without drama. On the day of this interview, Twinkle nearly escaped on the bike ride into campus.

“I was sitting at the traffic light crossing at Barry Drive and I looked down into the bike basket and noticed that this lizard is three quarters of the way out,” Pepper says.

For now, she’s making do with trinkets and screensavers to spruce up her office. On her windowsill is a rock collection from fieldwork trips.

There’s the gecko puppet looming over academic textbooks. The Queensland Museum had it on display, but found it scared visiting children too much.

“That was just taken at the end of last year in Big Red, which is right at the edge of the Simpson Desert,” she says of the image on her desktop.

Tour guides

Animals were always a passion for Pepper, but she didn’t follow the traditional route to becoming an evolutionary biologist.

“I was doing geology and music, actually, of all things,” she says. “I got into biology kind of late in the piece.”

She decided to pursue biology in her second year of university. A geology lecturer suggested she speak to Professor Scott Keogh, an expert in phylogeography and the biology of Australian frogs and reptiles.  

“I rocked up to Scott’s office, saying hello, you don’t know me, I don’t actually do any biology, but I’m really interested in animals,” Pepper recalls.

After the project, Pepper knocked on Keogh’s door once again.

“The third time I went to his office he said, ‘how would you like to do honours’ – he just took a chance on me,” she says.

Keogh’s office, where he’s building evolutionary trees based on DNA data from all the frogs and reptiles in Australia, is now right next door to Pepper’s.

“It’s been almost 25 years that I’ve known him now. I did honours with him, I did a PhD and then he supported me as a postdoc for many, many years before I got my own research funding,” she says.

“A lot my path has been about the teachers and their guidance.”

The can of Dr Pepper that sits on one of Pepper’s bookshelves takes on greater meaning with this backstory in mind.

“Scott [Keogh] used to give me these cans of Dr Pepper, because obviously I think that’s hilarious,” Pepper says.

Through the screensaver to the desert

Pepper wants to encourage more geologists to explore how living creatures can be a way to understand Australia’s geological history.

“The little geckos that are running around on those sand dunes now, they are so much more than just their species,” she says.

“All of their genetic makeup has been influenced by the landscape that existed before those deserts were there.

“There’s all these question marks. And I get to come along and look at the landscapes and put it all together.”

One lingering question for geologists is how old Australian deserts are.

“It’s not an easy thing to do – to date sand dunes – it’s also not easy to get to all of the desert areas. It’s so inaccessible,” Pepper says.

“It’s the same for biological collections, we don’t know much about the animals there either.”

Genetics from today’s living animals can show when populations grew or declined and when they passed through ‘bottlenecks’ – times when their numbers dropped so low that only a small group survived to pass on their genes. This can provide clues around changes in environmental conditions, such as the formation of deserts.