Evolution & Molecular Ecology

“Nothing in biology makes sense except in the light of evolution”. Theodosius Dobzhansky’s iconic quote serves as a guiding principle behind the EME theme. We are interested in deepening our knowledge of the evolutionary processes that shape biodiversity, across systems and at all scales. While the tools of molecular genetics are commonly employed by members of the theme, our projects also involve experimental ecology, modelling, long-term population studies, behaviour and the development of theory, amongst other methods and approaches. Research in EME informs conservation practice and policy as well as adds to our basic understanding of evolution.

Much of our current research falls under 3 broad topics:

Genetic variation and distribution

Genetic variation provides the raw material for natural selection, and thus determines a population’s adaptability to its changing environment. Populations with low genetic variation have a higher risk of extinction in the short term (due to inbreeding depression) and long term (due to poor adaptation), while populations with high genetic variation can adapt to more extreme environments at a faster rate. Projects in this topic assess the amount of genetic variation (neutral and adaptive) and its distribution at all hierarchical levels of the tree of life (e.g. molecular, individual, population, species). Our goal is to determine the genetic mechanisms (e.g. mutation, selection, migration, genetic drift) leading to the observed patterns of genetic variation.

Current projects include studies on developing population genetics models and methods to infer migration, population size, relatedness and pedigree from marker data (Jinliang Wang), on population structure of Ethiopian wolves and relatedness and mating system of cheetahs ( Dada Gottelli ) and on the inbreeding depression and adaptation of reintroduced bird populations in New Zealand ( Patricia Brekke ). Other researchers are describing the genetic variation and structure of Sumatran tigers in Sumatra, Indonesia (Tola Oni), the invasion genetics of grey squirrels in Europe (Lisa Signorile) and the population genetics and phylogeography of okapi in Congo ( David Stanton). We are also investigating the evolutionary genetics of cooperation in the Kalahari meerkats of South Africa (Johanna Nielsen), the population connectivity of cold water octocorals of the North Atlantic (Chris Yesson), and the nesting distribution and foraging distances of several bumblebees in the UK (Stephanie Dreier).

Genomic basis of phenotypic plasticity

An individual’s ability to alter its phenotype in response to the environment is fundamental for adaptation and evolution throughout the natural world. Determining how such phenotypic plasticity arises at the molecular level and how plasticity is constrained is essential for understanding the dynamics of evolution and adaptation in natural populations. This is especially important in today’s rapidly changing environment, where survival of individuals, populations, species, communities and ecosystems demands fast and responsive adaptation. Until now, research on the molecular basis of plasticity in non-model organisms in natural populations has been constrained by available technology. Moreover, it has been largely restricted to assessing genetic variation. Non-genetic variation [e.g. changes in gene expression (transcription) and epigenetics ( chemical modifications of genomic material)] has been largely untouched. New methodologies in molecular biology now allow all facets of genomic variation and plasticity to be examined in any species and in ecologically relevant contexts.

In EME we utilise next-generation sequencing technologies to expose and understand the genetic, transcriptomic and epigenetic components of the genome that underlie phenotypic plasticity in a range of model and non-model organisms. We are currently exploring how alternative phenotypes arise within societies of eusocial insects [Polistes paper wasps ( Seirian Sumner ), honey wasps (Elli Leadbeater), dinosaur ants (Claire Asher)], and in response to ontological and environmental cues in Atlantic salmon ( Kate Ciborowski ). We are also exploring how variation of virulence is maintained in pathogens (Rhys Farrer).

Coevolution: Conflicts and compatibilities

Genes, genomes, individuals and species do not operate in a vacuum. Other biological objects exert influence, and as a result impose change, a process referred to as coevolution. Coevolutionary processes can result in mutually beneficial relationships, such as what sometimes occur between a plant and its pollinator, but many arise through antagonistic relationships (e.g., predator-prey, host-parasite). In some cases, both types of relationships can be evinced in coevolutionary dynamics (e.g., sexual selection). Research in our theme involves determining at what biological scale coevolution occurs and how coevolution may shape adaptive potential, such as in populations of threatened and genetically depauperate birds (Patricia Brekke), amphibians and yellow dung flies ( Veronica Gomez-Pourroy, Trent Garner).

Worryingly, many coevolutionary relationships have become unbalanced, and the activities of humans are commonly implicated as a cause of destabilization of coevolutionary dynamics. Pollinators are in decline, infectious diseases are putting host species at risk of extinction, and many predator species are suffering due to reduced prey availability. Our basic research questions are often designed to investigate the consequences of destabilization for species and population persistence. Current projects include pathogens associated with the global decline of amphibians, Batrachochytrium dendrobatidis ( Rhys Farrer , Aisyah Faruk, Peter Minting, Jennifer Sears, Emma Wombwell, Frances Clare, Dave Daversa, Jon Bielby) and ranaviruses ( Stephen Price ).