1 research outputs found
Genes acting in synapses and neuron projections are early targets of selection during urban colonization
When a species colonizes an urban habitat, differences in the environment can create
novel selection pressures. Successful colonization will further lead to demographic
perturbations and genetic drift, which can interfere with selection. Here, we test
for consistent urban selection signals in multiple populations of the burrowing owl
(Athene cunicularia), a species that colonized South American cities just a few decades
ago. We sequenced 213 owls from three urban-rural population pairs and performed
a genome-wide comparison of urban against rural birds. We further studied genomewide
associations with flight initiation distance, a measure of harm avoidance in which
urban and rural birds are known to differ. Based on four samples taken over nine
years from one of the urban populations, we investigated temporal allele frequency
changes. The genomic data were also used to identify urban-specific signatures of
selective sweeps. Single genomic sites did not reach genome-wide significance for
any association. However, a gene-set analysis on the strongest signals from these
four selection scans suggests a significant enrichment of genes with known functions
related to synapses and neuron projections. We identified 98 genes predominantly
expressed in the brain, of which many may play a role in the modulation of brain connectivity
and consequently in cognitive function and motivational behaviour during
urbanization. Furthermore, polymorphisms in the promoter region of the synaptic
SERT gene – one of the two candidates known to correlate with urban colonization in
birds – associated with the habitat in which individuals lived (urban vs. rural).Peer reviewe