The adaptable genome

A large parts of the genome has evolved to deal with the ecological interactions of an organism with its environment. Most of the traits or processes that have evolved for these interactions are complex, with many genes involved, and often the ability to respond to variation in the environmental conditions. For the analysis of such a complex genetic architecture of traits and processes, the genomic toolbox is required. These tools allows us, for the first time, to trace the impact of the ecological interactions on the evolution of the genome. We aim to elucidate the genomic variation and genetic networks underlying the evolution of complex traits in ecological interactions, using a combination of experimentation, genomic approaches and bioinformatics.

We study the evolutionary genomics of ecological interactions in Drosophila fruitflies, where we can combine our extensive understanding of their ecology with the formidable molecular toolbox and knowledge on mechanistic processes for various life history traits. In my group, we investigate the changes in the genome that occur during 1) host-parasite co-evolution, 2) competitive turf wars for food, 3) sexual conflicts, and 4) the composition of the microbiome.

1. Host-parasite co-evolution

Parasitoids are insects that lay their eggs in or on other insects (their "hosts"), which are eventually killed while the developing parasitoid feeds on the host. To survive the lethal infection by parasitoids, some species of Drosophila can launch a potent cellular immune defense. The ability to resist parasitoid wasps varies hugely, both among and within species of the Drosophila genus, from completely absent in some species and natural populations to high resistance in others. Using a combination of phenotypic assays and genomics approaches, we identify genomic changes associated with gains and losses of parasitoid resistance. By studying and exploiting the large variation in immunity within and among Drosophila species, we aim to better understand the intricate genetic networks that underlie variation in immunity, and to map how the genome changes during the evolution of immunity. 

IPM strategies for the invasive Drosophila suzukii

The Spotted Wing Drosophila (SWD), Drosophila suzukii, is an invasive fruit fly from Asia that infests ripening fruit. It is rapidly spreading north in Europe and already causes millions of euros of damage in the fruit industry. We aim to capitalize on our extensive expertise in Drosophila chemical ecology, insect reproduction, insect evolutionary genetics, and interactions with parasitoids and pathogens, to develop innovative and locally attuned approaches for the management of this invasive pest. 

2. Competitive interactions 

Competition among species is a major organizing force in community ecology, and species can evolve complex strategies to survive competition. Two major players for ecosystem function are filamentous fungi and insects, and the turf wars between these taxa resulted in various adaptions and counter-adaptations. Fungi can engage in chemical warfare producing various insecticidal toxins, while insects can evolve detoxification mechanisms, immunity and behavioural adaptations (“social immunity”).

3. Sexual conflict

In many animals, including humans, males release both sperm and semen inside the female’s body during sex. The effects of semen proteins can benefit both sperm and eggs, but intriguingly they can also favour the interests of males whilst generating costs in females, resulting in sexual conflict. This manipulation of one sex by the other through molecular interactions was discovered in studies using the fruitfly Drosophila melanogaster. One enigmatic semen protein of the fruitfly, ‘Sex Peptide’ (SP), generates strikingly diverse changes in the behaviour, reproductive and immune system of the female. These changes benefit males by increasing their share of paternity, but can also result in costs in females, therefore mediating sexual conflict.

4. Microbiome

The billions of microbiota that live inside the body of an organism (‘the host’) have a much larger impact on the host than was previously appreciated. The immense community of microbes that reside in the gut, the skin or anywhere else in the body is collectively known as the microbiome. Recent experimental evidence emphasizes the huge influences of the microbiome on the phenotype of the host. The composition of the microbiome of a particular host is greatly dependent on the food, on environmental factors and on genetic factors of the host itself.