Adaptation and quantitative trait evolution in an urban context
By Anne Charmantier, CNRS, Montpelier, France
Biography: Anne Charmantier is an evolutionary ecologist interested in between-individual variation of life-history, morphological, and behavioural traits in natural populations. She holds a senior CNRS position (eq. Prof) in the Centre d’Ecologie Fonctionnelle et Evolutive (CNRS, UMR 5175, Montpellier, France). Her main research interests are focused on understanding the mechanisms involved in the evolution of adaptive traits, especially in a context of climate change and urbanisation. Since 2007 she has been managing a blue tit/great tit project dating back from 1976, which offers unique opportunity to study adaptation in heterogeneous and rapidly changing environments. In 2014, she published the OUP book ‘Quantitative Genetics in the Wild’ with Profs. Dany Garant and Loeske Kruuk.
With its conspicuously altered ecological dynamics, the urban environment stands in stark contrast to the natural environment that has been used as research ground for virtually all long-term studies used as cornerstones in evolutionary ecology. Because of this ecological contrast, it is often assumed that new phenotypes found in cities are the result of an evolutionary response to novel selection shaping genomic variation. In this talk, I will argue that urban environments offer exciting perspectives to investigate processes of rapid adaptation, using combinations of approaches, in particular quantitative genetics and genomics. Results from a project on great tits Parus major along an urbanisation gradient will illustrate the potential of studies on urban local adaptation. This study revealed phenotypic divergence for a large set of avian morphological, behavioural and life history traits: e.g. birds in the city are smaller, more aggressive, and breed earlier and smaller clutches. First, the genetic architecture and evolutionary potential of these traits was explored using animal models based on long-term field pedigrees and genomewide relatedness matrices. Second, comparing natural selection in forest versus urban habitats failed to support the hypothesis that contemporary selection explains phenotypic differences between urban- and forestbreeding great tits. Third, (epi)genomic investigations using RAD- and RRBS- sequencing revealed an effect of urbanisation on (epi)genetic diversity with numerous (epi)genetic regions showing elevated divergence,
suggestive of a polygenic adaptation. These findings open exciting perspectives for broader investigations of genomic bases related to adaptation in urban environments, notably in relation to avian personality and metabolism.
