Projects related to biodiversity genomics
Impact of radiation on species fitness
Higher organism rely on their cognitive abilities to compete for resources such as food, territories and mates: brain function is thus directly linked with fitness. There seems to be a link between brain size and cognitive performance at least in humans, since microcephaly usually goes along with cognitive disabilities. Development of the brain is sensitive to the environment, with stress during early life negatively affecting brain development, functions and cognition. Here, together with Dr. Zbyszek Boratynski, we aim to decipher the transcriptome and co-expression network signatures that determine brain size using two species of wild rodents (Apodemus and Myodes) from Chornobyl (Ukraine). We sequence the transcriptomes of the frontal cortex, hippocampus, amygdala, and motor cortex from individuals inhabiting areas with contrasting levels of soil radionuclide contamination to determine differences in gene expression and co-expression networks. From the very same individuals we also obtained measurements on their performance in behavioral tests, their basal metabolic rate, and brain mass to link the transcriptome patterns to energetic costs, brain size and cognitive performance.
Genetics of mating behavior and reproductive success
Social behaviors involve the interactions of one individual with another and are related to mating and reproduction success, hence fitness. The genetic basis of complex phenotypes typically involves a large number of genes. For example, much of the variation in social behaviour observed among vertebrates can at least in part be explained, by variation in gene expression networks located in the brain. In the project with Dr. Clemens Küpper, we use a highly amenable vertebrate study system, the Ruff Philomachus pugnax, to study how an autosomal inversion modifies gene expression and regulation and ultimately leads to discrete variation in male aggression and courtship. Our project involves the assembly and annotation of the ruff genome, comparative transcriptomics in a broad range of brain regions and other tissues in adult and young individuals.
Repeated evolution and loss of pollen-collecting structures in bees
The loss of phenotypes represents a type of evolutionary innovation and is a widespread phenomenon. Like phenotypic gain, it can be adaptive and lead to new life histories. However, compared to phenotype gain, it is less well studied. A particularly interesting case for evolutionary studies is the repeated loss of the same phenotype in independent lineages, because this allows for investigating the repeatability, and to some extent predictability, of evolution. Here we study the genomic basis of repeated phenotypic loss using pollen-collecting structures as example. These structures have evolved in several independent bee lineages and facilitated the evolutionary success of these lineages as pollinators. Interestingly, they have been lost in more than a dozen independent lineages of kleptoparasitic bees, along with certain behaviors and pilosity. In our project with Dr. Eckart Stolle, we produce and analyze more than 100 bee genomes to reveal the emergence of that phenotypic loss within a phylogenetic framework. As pollen collecting structures seems to be gained and lost dynamically during evolution, we hypothesize that gene regulatory changes play an important role in achieving such phenotypic plasticity. Hence, we also produce transcriptomes and ATAC-Seq data from six species, precisely three pairs of host and kleptoparasitic species having gained or lost the structures. In addition, we will investigate shifts in selective pressures acting on coding and non-coding sequences to understand how they might have conveyed the repeated loss of pollen collecting structures.
Comparative skylight navigation
The sun and the sky are amongst the most ancient visual cues for terrestrial navigation. Navigation skills are essential for successful hunting, foraging, or dispersal of most free-living species. Insects use different visual stimuli, like celestial bodies and skylight polarization. While systematic morphological characterization has identified retinal detectors for polarized skylight in virtually all insects analyzed, it remains unknown whether specification of these structures and their underlying neural circuitry are in fact evolutionarily conserved. Moreover, it is unknown how they are adapted to the diverse ecological niches of different insect species. In this proposal, together with Prof. Mathias Wernet, we are investigating how variations in the transcription factor networks shape the skylight detector system in adaptation to species-specific demands. We are using a combination of different bioinformatics methods to compare regulatory sequences, transcription factor binding sites, transcription factor networks, and gene expression profiles across insects, including flies, butterflies, mosquitos, bees and others to reveal evolutionarily conserved mechanisms as well as species-specific adaptations behind the formation of neural circuits for insect skylight navigation.
Primate sociality and fitness
Kin-driven behaviour influences social relationships and can have crucial importance for health and fitness of individuals. Notably, the amount of the genome shared by relatives varies considerably due to stochastic processes during meiosis, resulting in a gradient of IBD (identity-by-descent) values. In this project with Anja Widdig, we will take advantage of a population of free-ranging rhesus macaques (Macaca mulatta) at Cayo Santiago (Puerto Rico), for which demographic, reproductive, behavioural, and other phenotypic data have been collected over decades. We will sequence the whole genomes of ~1000 of those rhesus macaque individuals to determine their IBD to assess the impact of the gradient in IBD on social preferences for and against kin. With this project we aim to contribute to understanding how realized relatedness shapes sociality and biodiversity.