Format: ORAL

Erika J. Edwards1, Michael J. Donoghue1

1Department of Ecology and Evolutionary Biology, Yale University, New Haven CT, USA

What makes a clade a model clade?In our view it is not because it provides a good example of some particular phenomenon or process. This, we think, is true of every clade. Likewise, it is not because it is a clade that includes a model species such asArabidopsis thaliana. Nor is it because it somehow represents a microcosm of the variety manifested by a more inclusive clade. Instead, we adopt the view that a model clade is simply one that has been studied intensively and from many different angles, leading naturally to a more holistic understanding. The expectation is that this concerted, integrative attention to a group of organisms will yield insights that would not otherwise be attainable, and this accumulation of context will invariably improve our interpretation of any one study in isolation. We view this context as critical in evaluating macro-evolutionary data and predict that studies of model clades will continue to provide the most compelling explanations of organismal evolution. Although there are no rules for the development of a model clade, there are some things that are foundational in providing a platform for diverse studies. One key element is the development of a firm understanding of phylogenetic relationships and of a phylogenetic classification system to support unambiguous communication across labs and generations. An additional consideration is clade size. There are distinct advantages to clades of moderate size large enough to support convincing statistical analysis, but not so large that comprehensive surveys become too challenging.Viburnum(Adoxaceae) provides an example of a model clade in the sense that we have outlined here, and we will provide concrete examples of novel insights that have emerged as a consequence of having carried out a diverse set of studies ofViburnumover multiple decades.