- I'm really excited to see this paper by @fernpizza.bsky.social, @baym.lol, et al. This is a great model system for studying multilevel selection, and the experimental work builds nicely on cross-scale theoretical modeling approaches that I've enjoyed learning about over the past few years. 🧵
- Hot off the press! Our latest paper led by @fernpizza.bsky.social, understanding how plasmids evolve inside cells. These small, self-replicating DNA circles live inside bacteria and carry antibiotic resistance genes, but also compete with one another to replicate. 1/ www.science.org/doi/10.1126/...
- Here is one of my favorite papers, "A unifying framework reveals key properties of multilevel selection" by Shishi Luo. Luo highlights examples of multilevel selection and introduces a nested birth-death process to model evolutionary competition across scales. www.sciencedirect.com/science/arti...
- Luo considered two strategies: cheaters with an individual-level replication advantage and cooperators that conferring a collective replication advantage to its group. Luo formulated a stochastic model for individual and group dynamics, deriving ODE and PDE models in the large population limit.
- Mathematically, Luo's model is particularly tractable due to the choice of a nested birth-death process of individuals and groups. Biologically, the plasmid system of @fernpizza.bsky.social et al fit this approach so nicely because the plasmids replicate independently but impact cellular fitness.
- Luo and @jonathancm.bsky.social derived and analyzed PDE and Fleming-Viot scaling limits in the limit of infinitely many groups and infintie group size, characterizing the strength of group-level selection required for survival of cooperation in the PDE model. iopscience.iop.org/article/10.1...
- Analysis of this two-level Moran model has led to a lot of other interesting work in probability and PDEs. In one interesting paper, Aurélien Velleret studied quasi-stationary distributions in a diffusive PDE model that arises in the limit of weak selection. www.aimsciences.org/article/doi/...
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- Donald Dawson also explored the behavior of the Fleming-Viot limit, using a dual process to study the extinction or survival of cooperation due to selection, mutation, and drift at both the individual and group levels. link.springer.com/article/10.1...
