Developing a quantitative theory of adaptive evolution
Life on earth exhibits an astonishing variety of adaptations. Darwin famously outlined how natural selection acting on heritable variation might produce these adaptations over many generations. Today, with modern DNA sequencing technology, we are able to observe the dynamics of adaptive evolution in its full genetic complexity, down to changes of individual DNA nucleotides. However, it is still a major challenge to link the genetic patterns that we observe in DNA sequence data to the ecology and evolution of adaptive traits. I develop mathematical models to understand how ecological, evolutionary and genetic processes combine to drive adaptive evolution, and what signatures those processes leave behind in DNA.
The interplay between ecology and evolution
Deciphering the interplay between ecology and evolution is one of the major unsolved problems in modern biology. On the one hand, the interaction of a population with its environment determines which phenotypic traits are favored by selection. On the other, trait evolution changes the interaction of the population with its environment, thereby affecting the structure of the ecological community in which the population lives. The resulting eco-evolutionary dynamics are complex, but we must make sense of these dymamics if we are to understand how and why different traits evolve.
Genetic factors in evolution
On top of the issue of understanding the interplay between ecology and evolution at the level of phenotpyic traits, we are still grappling with how genetic processes shape evolution. For example, genes are physically linked in DNA (“linkage”), and thus their evolutionary fates can be coupled even if they have largely unrelated roles in the organism. Linked selection makes it harder for evolution to simultaneously address multiple challenges, and causes adaptive mutations to compete with – and potentially eliminate – each other. Genetic processes interact with eco-evolutionary processes at the trait level to govern the overall course that evolution takes.
Understanding eco-evolutionary dynamics in the presence of genetic constraints has many important applications. For example, I have developed models to explore the evolutionary dynamics of extinction, an important current issue given the pressures imposed by humans on natural ecosystems. I have also worked on rapidly evolving fruit fly populations to understand how their impressive levels of genetic variation might be maintained by seasonal variation in their environment. For a full publication list, please see my Publications or CV.