Recurrent adaptation to industrial pollution: ancestral diversity and ecological succession

Natural populations adapt to novel environments via phenotypic variation that has its origins either in contemporary mutation events or in pre-existing ancestral variation, or both. Understanding the significance of these modes of evolution in real ecological settings is central to predicting the speed of adaptation to novel challenges, and thus to informed population management intervention in the face of environmental change - but we lack suitable empirical studies. Industrial melanism in the peppered moth (Biston betularia) has emerged as a top candidate for such a study. In Britain, the black (carbonaria) form is due to a singular recent mutation, whereas in continental Europe, preliminary data suggests a surprising diversity of mutations, some of which may be adapted to a pre-industrial and pre-agricultural, forest-dominated landscape. Thus, the celebrated British case may not be generally representative of the evolutionary origins of industrial melanism across the species' range. Natural heterogeneity in resting backgrounds, associated with successional turnover and extensive mature forests, may be the unrecognised factor maintaining the striking diversity of melanic forms in this species. By revealing the identity of the mutations causing melanism in continental European populations, estimating their age, and evaluating non-industrial environmental factors maintaining melanism, this project will resolve a major puzzle in this influential evolutionary biology case study, whilst at the same time providing a novel illustration of how the interplay between genomic architecture, ecology, and geographic isolation influences mechanisms of evolution.

Industrial melanism in the peppered moth is used by educators worldwide as an easy to appreciate example of rapid evolution. But the material in school and university textbooks has become somewhat worn, and is lagging behind our research findings on the genetics of the system. Making use of the familiar storyline, these provide a great opportunity to introduce new concepts and details that are of general importance to a deeper understanding of evolutionary biology and genetics. The topics would include DNA mutation, transposable elements, genetic recombination, the effect of strong selection on genetic diversity, and parallel evolution. In order to give our results the widest reach, we will make them publicly available in an accessible style through Wikipedia. The 'Peppered moth evolution' page, which receives 150-500 views per day, provides an excellent platform for sharing our knowledge on the evolutionary genetics of the system, which is currently lacking from the page.