Feedback by Maria Del Pilar Herrera Egoavil

By: Maria Del Pilar Herrera Egoavil

On August 11^th, 2025, the Slim course led by Ben Haller took place on the campus of Viikki (Helsinki, Finland). The course had an intense pace, but it was well structured, so it wasn’t hard to follow and grasp the important information. We started with the basics, getting familiar with the program language, the structure for modifying parameters, and setting up some very simple simulation examples. For the first three days, we centred on Wright-Fisher models and simulations more closely related to population genetics questions. Yet during the final two days, we also learned to run simulations with non-Wright-Fisher models and applied them to questions in quantitative genetics and ecology. Even when Slim’s purpose is to perform forward simulations, Ben showed us that Slim could also perform backwards simulations when combined with other Python-based packages created by other Slim users. We also had invited speakers who have addressed complex questions using Slim or incorporated Slim into a more complex workflow.

Thus, the program seems to have almost limitless potential to simulate many scenarios and address questions in evolutionary biology, quantitative genetics, trait evolution, genome architecture, demographic events, and so on. Given that potential, it will be good to incorporate it more into our studies of tree genetics, evolution, breeding, forest dynamics, etc.