Urban life shapes genetic diversity in the green anole, Anolis
carolinensis.
Abstract
Urbanization presents unique environmental pressures that drive rapid
evolutionary adaptations, particularly in species inhabiting fragmented
and anthropogenic landscapes. In this study, we investigate the genomic
differentiation between urban and non-urban populations of Anolis
carolinensis, focusing on two main aspects: (1) the effect of habitat
fragmentation on inbreeding and mutational load (2) genomic adaptation
to the urban habitat. Using genome-wide scans of selection and analyses
of genetic diversity, we identify key genomic regions exhibiting
significant divergence between urban and non-urban populations. These
regions are enriched for genes associated with immunity, behavior, and
development, suggesting that urban adaptation is polygenic and involves
traits related to stress response, locomotion, and thermoregulation. By
comparing candidate genes linked to urban adaptation in another Anolis
species, A. cristatellus, we detect potential signatures of convergent
evolution in loci involved in immune response and behavior, further
supporting the hypothesis that urban environments exert similar
selective pressures across species. These results provide evidence for
polygenic adaptation and highlight the complexity of urban evolution.
Future work with denser population sampling and time-series data will be
essential to confirm the role of urban selective pressures and track the
genetic dynamics of urban populations over time.