Research

Our research focuses on the evolution and diversification of  morphological traits – how they are genetically and developmentally determined, and what are the selective forces that shape them. We combine developmental genetics, quantitative and population genetics and behavioural techniques. Combining approaches brings a more comprehensive understanding of biodiversity. 

The pigmentation patterns of lake Malawi cichlid fishes provide an ideal system to study morphological evolution. We focus on a set of brightly pigmented spots on male anal fins, known as “egg-spots”. Egg-spots are a diverse trait (number, colour and shape), and play a key role in the territorial and breeding behaviour of around 1,500 species of cichlids. They are relatively simple structure, consisting of a circular area made up of xanthophores and iridophores (orange and silver pigment cells respectively) and are often surrounded by a transparent outer-ring.

With the availability of dozens of cichlid species genomes and genome editing tools (eg. Tol2 transgenesis and CRISPR), we can link genetics, cellular biology, development, phenotypes and organismal trait function. By addressing these mechanisms across different timescales (populations, species and genera) we can tackle a long-standing question: whether the basis of adaptive change is the same at the micro- and macro-evolutionary scale. 

Ongoing projects

Microevolution of egg-spot patterns in Astatotilapia calliptera from lake Massoko

more info coming soon

Mechanisms of egg-spot emergence and diversification in Lake Malawi cichlids

more info coming soon

Evolution of developmental trajectories

more info coming soon

Previous projects

Evolution of a novel trait in Rhagovelia sp.

Here we study the developmental genetics of the origin of a novel trait that was essential for the invasion of a novel environment.

The Rhagovelia propelling fan is a tarsal cuticular structure present in the second leg of these bugs. It is thought to be a key innovation that facilitated the invasion of fast flowing waters by this group of semi-aquatic rowing insects.

 In Rhagovelia sp. (genus of water-walking insects; Heteroptera, Gerromorpha) the evolution of a highly elaborate swimming fan on the tarsus of the propelling mid-legs increases water resistance against leg movements, thereby increasing their propelling function. We showed that this novel trait acted as a key innovation, allowing this group to conquer and diversify on running water surfaces; a niche that is not accessible for most other water-walking insects. 

Little is known about the underlying genetic mechanisms and their role in the diversification of the group. We are characterizing the genes and the specific genetic changes that underlie the emergence of  the Rhagovelia propelling fan. The function of these genes is tested with functional experimental studies  by changing the expression of such genes (RNAi). Finally we manipulate the phenotype (through manipulation of it’s underlying genes) and access how it affects organismal fitness (by competing the knock-down with the wild-type phenotype in a controlled environment). We this approach we will be able to pinpoint which genetic changes lead to phenotypic changes and ultimately which phenotypic changes have a fitness impact on the organism ability to walk on water. This approach is highly innovative, as it will directly connect molecular and developmental changes in a key trait to a measure of fitness.