Eva van der Heijden
I am a PhD-student in the group of Joana Meier. My PhD focuses on the genetics behind wing colour patterns of brightly-coloured toxic tropical butterflies. I am interested in examining genes that are important for diversity of colour patterns, for which I use techniques like CRISPR-Cas9, in situ hybridization and antibody stainings.
Colour patterns in tropical butterflies
I work on the genetics of wing colour patterns in ithomiine butterflies called Melinaea and Mechanitis. The butterflies I am interested in are brightly-coloured, to signal to predators that they are toxic and should not be eaten. In certain locations, toxic butterflies from different species have evolved very similar colour patterns, which helps teaching predators to avoid them. In different locations, different colour patterns have become the dominant colour pattern. I am investigating how the same colour patterns in different species have evolved, and how different colour patterns in the same species have evolved. Studying these questions help us to understand the evolution of different phenotypes, and the genetics behind the early stages of speciation.
The colour patterns I am studying are black-orange butterflies with or without a yellow band on their forewing. In the Mechanitis butterflies, I have found that a particular gene called ‘cortex’ is important for the difference in the presence of the yellow band. At the moment, I am investigating whether the same gene is important in the formation of a very similar phenotype change in Melinaea butterflies.
To further investigate the function of the cortex-gene, I have done knock-out experiments in Mechanitis with CRISPR-Cas9. This caused the adult butterfly to have patches of yellow scales where there shouldn’t be any, thereby proving that cortex is important for the colour of the scales. A knock-out of cortex changes the wing colour pattern of the adult butterfly. I am now investigating the expression pattern of cortex through in situ hybridization experiments and antibody stainings.
Before starting my PhD, I worked on cortex in Heliconius butterflies, where it is also related to the formation of certain wing colour patterns.
Most of the projects I have worked on in the past were related to speciation and the evolution of different phenotypes. During my bachelor, I worked on pigmentation genes in Petunia flowers. During my master, I worked on the evolution of pigmentation patterns in Drosophila, as well as ovariole development in Drosophila. I also studied questions related to speciation and the microbiome in European crows, speciation and metabolic rate in European flycatchers, and the hybrid zone of Australian long-tailed finches.