The genetic basis of convergence across evolutionary time
Lead Research Organisation:
University of York
Department Name: Biology
Abstract
Convergent evolution, the independent acquisition of similar traits in multiple lineages in response to the same selective pressures, is ubiquitous, facilitating adaptation and diversification across the tree of life. Therefore, understanding the genetic mechanisms by which convergence occurs is critical if we are to understand adaptations that already exist, and the predictability of evolution in response to common selection pressures. We propose to study mimetic convergence across the Lepidoptera using high-throughput sequencing and gene expression analyses to address a major challenge in this field: the contributions of different genetic mechanisms to convergence across evolutionary timescales. This will be the first genetic analysis of convergence for a trait evolving under the same selective force over 2-110 million years of evolution and will uncover the genetic landscape of convergence across evolutionary time.
The genetic changes causing convergence can be categorized as divergent genetic mechanisms, parallel evolution, or collateral evolution. We hypothesize that these three processes act at different evolutionary time scales. Most recent understanding of convergent evolution has focused on parallel and collateral evolution among closely related species. We lack studies that investigate the genetic basis of convergence over a range divergence times (from recent to deep time) for a single trait under the same selective force. Only by considering convergence among lineages that split anywhere from a few million to 100 million years ago, or more, can we understand the overall frequency distribution of the genetic mechanisms of convergence.
The relative contributions of the three genetic mechanisms will impact on the tempo and direction of evolutionary convergence. For example, interspecific hybridization can greatly facilitate convergence among closely-related species, yet its contribution to convergence is largely unknown. We also lack knowledge of the genetic basis of deep time convergence. An important unanswered question is whether convergence between distant lineages is difficult to evolve. Alternatively, is convergence aided by the existence of conserved genetic architectures and developmental pathways, which may facilitate parallel evolution even after 100 million years of separation?
We propose to tackle these fundamental questions about the genetic mechanisms of convergence by exploiting a unique system in the Lepidoptera in which multiple species have converged on the same defensive wing colour patterns across a wide range of evolutionary timescales (2-110 million years). We will use a combination of fieldwork, gene expression analysis and the latest high-throughput sequencing technologies to identify and verify genes responsible for convergence in multiple butterfly and moth species. These data will allow us to assess the relative contributions of divergent genetic mechanisms, parallel and collateral evolution to convergence among 18 species of butterflies and moths representing 2-110 million years of evolution, and will allow us for the first time to visualize the genetic landscape of convergent evolution for a single trait evolving under the same selective force across a wide evolutionary timescale.
The genetic changes causing convergence can be categorized as divergent genetic mechanisms, parallel evolution, or collateral evolution. We hypothesize that these three processes act at different evolutionary time scales. Most recent understanding of convergent evolution has focused on parallel and collateral evolution among closely related species. We lack studies that investigate the genetic basis of convergence over a range divergence times (from recent to deep time) for a single trait under the same selective force. Only by considering convergence among lineages that split anywhere from a few million to 100 million years ago, or more, can we understand the overall frequency distribution of the genetic mechanisms of convergence.
The relative contributions of the three genetic mechanisms will impact on the tempo and direction of evolutionary convergence. For example, interspecific hybridization can greatly facilitate convergence among closely-related species, yet its contribution to convergence is largely unknown. We also lack knowledge of the genetic basis of deep time convergence. An important unanswered question is whether convergence between distant lineages is difficult to evolve. Alternatively, is convergence aided by the existence of conserved genetic architectures and developmental pathways, which may facilitate parallel evolution even after 100 million years of separation?
We propose to tackle these fundamental questions about the genetic mechanisms of convergence by exploiting a unique system in the Lepidoptera in which multiple species have converged on the same defensive wing colour patterns across a wide range of evolutionary timescales (2-110 million years). We will use a combination of fieldwork, gene expression analysis and the latest high-throughput sequencing technologies to identify and verify genes responsible for convergence in multiple butterfly and moth species. These data will allow us to assess the relative contributions of divergent genetic mechanisms, parallel and collateral evolution to convergence among 18 species of butterflies and moths representing 2-110 million years of evolution, and will allow us for the first time to visualize the genetic landscape of convergent evolution for a single trait evolving under the same selective force across a wide evolutionary timescale.
Planned Impact
Who might benefit from this research?
1) This research will benefit those working in science education
2) This research will benefit wider society through increased engagement with science
How might they benefit from this research?
1) Science education: Convergent evolution in Lepidoptera is an excellent system for teaching the principles of evolution because of the appeal of butterflies and moths, and because mimicry is a very visual example of convergence. Our research will provide examples of the different genetic mechanisms causing convergence across a range of evolutionary timescales. It will therefore provide an excellent evolutionary example for the classroom and one that would link across different areas of the curriculum from ages 11-18 (UK Key stages 3 and 4, GCSE, AS and A-levels; but also outside the UK). Lesson plans and teaching materials (videos, computer game, posters) will be developed and distributed via teaching resource websites. Our research will also be useful for teaching aspects of evolutionary genetics at undergraduate and postgraduate levels, including direct involvement with the research via undergraduate and Masters level research projects in the UK and Ecuador. Making science lessons more interesting and accessible will inspire young people to follow careers in science.
2) Public engagement with science: Lepidoptera hold a unique place in the public imagination as evidenced by the coverage that previous Heliconius work has received in the popular press, and the enthusiastic responses we have received at outreach events. This research would build on that interest and awareness, engaging the public in the UK, France and Ecuador with evolutionary biology. The appeal of Lepidoptera and tropical systems means that this work has the potential to inspire young people to pursue their interests in science. This is of general benefit for innovation and society.
1) This research will benefit those working in science education
2) This research will benefit wider society through increased engagement with science
How might they benefit from this research?
1) Science education: Convergent evolution in Lepidoptera is an excellent system for teaching the principles of evolution because of the appeal of butterflies and moths, and because mimicry is a very visual example of convergence. Our research will provide examples of the different genetic mechanisms causing convergence across a range of evolutionary timescales. It will therefore provide an excellent evolutionary example for the classroom and one that would link across different areas of the curriculum from ages 11-18 (UK Key stages 3 and 4, GCSE, AS and A-levels; but also outside the UK). Lesson plans and teaching materials (videos, computer game, posters) will be developed and distributed via teaching resource websites. Our research will also be useful for teaching aspects of evolutionary genetics at undergraduate and postgraduate levels, including direct involvement with the research via undergraduate and Masters level research projects in the UK and Ecuador. Making science lessons more interesting and accessible will inspire young people to follow careers in science.
2) Public engagement with science: Lepidoptera hold a unique place in the public imagination as evidenced by the coverage that previous Heliconius work has received in the popular press, and the enthusiastic responses we have received at outreach events. This research would build on that interest and awareness, engaging the public in the UK, France and Ecuador with evolutionary biology. The appeal of Lepidoptera and tropical systems means that this work has the potential to inspire young people to pursue their interests in science. This is of general benefit for innovation and society.