Ana Marija Jakšić Shapes Fruit Fly Brains

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Ana Marija Jakšić was born and raised in Zagreb, Croatia, the second oldest of four siblings. When she was young, her father took her on hunting trips that inspired an interest in animals. Jakšić initially attended a vocational high school for economics with the intent of continuing her family’s business of making sliding doors, but her attraction to the life sciences sparked again when she studied agriculture as an undergraduate at the University of Zagreb. Thereafter, her ambitions shifted towards establishing a dairy farm, and she graduated with a bachelor’s in animal science in 2012 before moving on to a master’s in animal genetics and breeding at the same institution.

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During her master’s research, Jakšić learned that “the most basic thing you need for agriculture is a very good basis in quantitative genetics, because everything is about breeding,” she tells The Scientist, adding that she “fell in love with genetics instantly.” In 2014, she began a PhD in population genetics at the University of Veterinary Medicine in Vienna, where she investigated experimental evolution in Drosophila under the mentorship of population geneticist Christian Schlötterer. 

Jakšić describes experimental evolution as the process of exposing organisms to different environments while tracking modifications to their genomes in real time. In her work, she might present flies with color cues that guide them to food, for example. The best-performing flies are then bred, and after multiple generations, “the shifts in frequencies of different gene variants in the population can actually give you a clue” about the genes driving changes in their performance over time, she says. 

Schlötterer recalls Jakšić’s energetic approach to tackling her research questions, noting that she “has great skill in pulling interesting signals out of these massive amounts of data.” Schlötterer adds that she was a strong example of a motivated student, pushing research beyond what was expected. 

Specifically, Jakšić investigated how Drosophila populations evolved when exposed to high or low temperature regimes, finding that “what was actually most impacted by temperature were their brains,” she says. For example, there was a noticeable difference in the way that certain neuronal genes were being expressed in warmer temperatures, and Jakšić found that the strongest and most consistent response was in dopamine-producing neurons, which dampened the expression of several genes involved in neural signaling. As a result, the flies developed higher levels of spontaneous locomotor activity, as measured by how fast they scaled the walls of a vial when startled (Mol Biol Evol, 9:2630-40, 2020).

In 2018, Jakšić began a postdoc at Cornell University with population geneticist Andrew Clark, who describes her as having a natural competence with “every aspect of fly genetics.” In his lab, Jakšić expanded on her previous research by artificially altering levels of dopamine in Drosophila. She says her goal was to investigate whether different genotypes are better able to “ameliorate” the locomotor changes, adding that she hopes the work will lead to insights into human conditions such as Parkinson’s disease, in which dopamine imbalances induce uncontrolled movement. The research was abruptly put on hold, however, after Jakšić was awarded a scholarship to launch her own research group at the Swiss Federal Institute of Technology Lausanne in 2019. 

Today, she is delving further into Drosophila evolution, investigating sex-specific differences in how dopamine homeostasis is maintained and how dopamine signaling and behavioral phenotypes in males and females respond to a hotter environment (eLife, 9:e53237, 2020), among other lines of research. Jakšić says that fruit flies continue to be a great model system because their genetic background is very easily manipulated, including the ability to silence “very specific types of neurons, which is quite important for the work that we’re doing in my lab.”

Starting her research group during the pandemic has been “challenging,” she notes, but adds that the lab has already welcomed multiple graduate students. Riddha Manna, a current PhD student who works on developing automated systems to perform behavioral assays on flies, tells The Scientist that one of his favorite parts of working in Jakšić’s lab is the interdisciplinary nature of the research and how his mentor makes everyone feel at home. Of her new lab group, Jakšić says that “it feels really exciting to work with all of them. The whole journey of the discovery . . . is something I very much enjoy.”