[CAEE] "Dating deep divergences: challenges and emerging strategies in Bayesian phylogenomic dating" by Dr. Sandra Álvarez-Carretero, University College London

Molecular clock dating, particularly under Bayesian relaxed-clock frameworks, has transformed our ability to reconstruct evolutionary timelines. Yet estimating deep divergences in the Tree of Life remains one of the most challenging problems in evolutionary biology. 

Deep timescales are typically constrained by sparse and often ambiguous fossil evidence, resulting in calibrated phylogenies with very few and unevenly placed node-age constraints. Integrating alternative sources of temporal information such as horizontal gene transfers, gene duplications, geochemical constraints, or experimentally derived mutation rates is therefore key for increasing the number of node calibrations, which can in turn help improve the accuracy and reliability of inferred timetrees. While these approaches extend clock-dating analyses into otherwise inaccessible regions of the tree, they introduce additional modelling assumptions and potential sources of bias. Conflicting results across calibration schemes and clock models highlight the sensitivity of deep-time estimates to methodological choices.

In this talk, I will discuss these limitations and explore reproducible methodological approaches that could help achieve more reliable reconstructions of ancient evolutionary timelines.

The talk is part of the Computational Approaches to Early Evolution Workshop (April 20-24, 2026)