CAREER: Mitonuclear conflict and co-evolution in a wild polyploid animal

Animal cells are partially defined by the relationship between their two different sources of DNA, one from the nucleus and one from the mitochondria. Efficient communication between these sources of DNA is essential for energy production and survival, and their compatibility can influence how species reproduce, regulate their physiology, and diverge from one another. Because the ongoing collaboration between the nucleus and mitochondria is foundational to survival, opportunities to study the consequences of miscommunication between these cellular components are rare. This project uses a unique group of all-female salamanders that possess an evolutionary distinct mitochondrial genome that is forced to interact with nuclear genomes taken from males of other species. How these salamanders have persevered for millions of years while managing their enormously complex genomic challenge can help us understand how other organisms suffer severe consequences when their mitochondrial and nuclear genomes produce conflicts. This project will integrate across biological disciplines from different universities and students will acquire training for careers in diverse, data-driven fields. At the same time, the data from this project will be directly integrated into university curriculum to forward initiatives that increase students’ data analytics and scientific communication skills.

Understanding how mitonuclear interactions evolve and are maintained is necessary for understanding the consequences of mitonuclear mismatch, whether due to new mutations or interbreeding between species and populations. To connect mitonuclear genotypes to functional phenotypes, this research includes measurements of sequence evolution, mitochondrial performance, and whole-animal metabolism. This will provide a comprehensive picture for how mitonuclear relationships in all-female salamanders have evolved and are maintained over millions of years in the face of frequent introgression. The first project aim will describe the evolutionary relationships between the mitochondrial and nuclear genomes being shared between salamander groups over generations and millions of years. The second aim will estimate measures of selection for genes originating from the mitochondrial and nuclear genomes that must interact to form basic metabolic pathways. The third aim will connect the molecular measurements to physiological performance at both organelle and whole-animal scales. The final aim will provide new whole-genome resources for salamanders to understand the genomic context of identified mitonuclear interactions. Despite their importance in biomedical, evolutionary, and ecological studies, salamanders have been an undersampled taxonomic group for genomic resources due to the technological challenges issued by large, repetitive genomes. This project will provide much needed genomic resources for salamanders broadly.

This project is jointly funded by the following programs in the Directorate for Biological Sciences: Evolutionary Processes in the Division of Environmental Biology, Genetic Mechanisms in the Division of Molecular and Cellular Biosciences, and Physiological and Structural Systems in the Division of Integrative Organismal Systems.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Award Number: 2554844
Principal Investigator: Rob Denton
Funds Obligated: $428,322
State: IN