Molecular approaches have revolutionised evolutionary biology since the late 50s. Today, molecular evolutionary biology is an integrated hybrid of mechanistic, mathematical and datafied research. I aim to show that the molecular conceptualisation of evolutionary dynamics provided by this hybrid has a significant mechanistic foundation. I shall first outline the biochemical roots of this foundation. Then, I shall illustrate how evolutionary causal chains are conceptualised in contemporary molecular evolution research. I shall finally argue that a fundamental innovation of molecular evolutionary models is dependent on the mechanistic understanding of the mutational and developmental processes causing the origin of traits. Thus, molecular evolutionary biology integrates proximate and ultimate causes, providing a variety of how-possibly and how-actually explanations.
Davide Vecchi (Wed,) studied this question.