Genetic variation
Dr. Jakob C. Mueller
In birds, little is known about genetic correlates of behavioural variation and its maintenance in nature. A first step is to identify functional relationships between genotypes or chromosomal regions and behavioural traits in natural bird populations. We ask where naturally occurring gene variants exist, and whether they are linked to the observed trait variation. We are interested in the genetic basis of behaviours such as specific personality traits, sex-specific behaviour, sleep and other rhythmic behaviour, dispersal, migration and characteristics related to habitat selection. Adaptive processes are analysed at the ecological and evolutionary time-scales by looking at direct fitness correlations in long-term data sets and by searching for genomic signatures of selection in study systems that underwent recent adaptation to a novel environment. The study of genomic conflicts based on sexual antagonism or inbreeding/outbreeding phenomena is a particular focus of our interests. We combine modern approaches of genomic and transcriptomic sequencing with new bioinformatic techniques for trait mapping, population genomics and tests for selection signals.
In burrowing owls, urban colonization leads to selection in genetic variants in genes important for cognitive function and motivational behaviour
Urbanization is increasing worldwide; most humans nowadays live in cities. Despite of the associated general decline in diversity due to habitat fragmentation, availability of resources or pollution, there are examples of species that successfully colonize urban habitats. Now, a group of researchers around Jakob Mueller and Bart Kempenaers performed a genome-wide comparision of urban against rural burrowing owls, a bird species that colonized South American cities just a few decades ago. Among other things, the researchers found in city birds selection signals in genes that act in synapses and neuron projections in the brain with potential control functions for cognitive and emotional behaviour and could thus play an important role in the adaptation to the urban environment.
(Image copyright: José L. Tella)
Great tits with character: Gene variant makes some great tit populations more curious than others
Similar to humans, individuals also have different personalities in animals. An important part of these individual differences is based on variation in the underlying genes. For example, the so-called dopamine receptor D4 gene influences the exploratory behaviour of a whole range of species, including humans and birds. However, scientists from the Max Planck Institute for Ornithology in Seewiesen have discovered that the influence of this gene on the behaviour of free-living great tits varies regionally. (Molecular Ecology, 09 February 2010).
Microevolution in blue tits
Microevolution also refers to adaptations that take place within a species’ population. Researchers at the Max Planck Institute for Ornithology have investigated this process in a blue tit population. They show that mutations and their frequency shifts in the population occur primarily in genes that regulate the activity of other genes. This confirms that, in addition to structural changes in proteins, it is primarily their regulation that is crucial for constant adaptations. In addition, many genes involved in brain development were found under selection, which might explain behavioral adaptations to new environmental conditions. The study thus provides insights into the selection mechanisms of a single bird population and its future evolutionary development.
Population structure of urban and rural populations of burrowing owls
The burrowing owl (Athene cunicularia) colonized South American cities a few decades ago. Researchers around Jakob Müller and Bart Kempenaers show in a new study that each city was independently colonized by a limited number of founders from the surrounding rural population, and not from a single source population spreading across all cities. The study was published in a special issue of "Proceedings of the Royal Society B" with the topic "The evolution of city life".