Adaptation in flower form: a comparative evodevo approach

Summary Evolutionary developmental biology (evodevo) attempts to explain how the process of organismal development evolves, utilizing a comparative approach to investigate changes in developmental pathways and processes that occur during the evolution of a given lineage. Evolutionary genetics uses a population approach to understand how organismal changes in form or function are linked to underlying genetics, focusing on changes in gene and genotype frequencies within populations and the fixation of genotypic variation into traits that define species or evoke speciation events. Microevolutionary processes, including mutation, genetic drift, natural selection and gene flow, can provide the foundation for macroevolutionary patterns observed as morphological evolution and adaptation. The temporal element linking microevolutionary processes to macroevolutionary patterns is development: an organism's genotype is converted to phenotype by ontogenetic processes. Because selection acts upon the phenotype, the connection between evolutionary genetics and developmental evolution becomes essential to understanding adaptive evolution in organismal form and function. Here, we discuss how developmental genetic studies focused on key developmental processes could be linked within a comparative framework to study the developmental genetics of adaptive evolution, providing examples from research on two key processes of plant evodevo – floral symmetry and organ fusion – and their role in the adaptation of floral form.ContentsSummary 74 I. Introduction 74 II. Evodevo and the regulatory hypothesis 75 III. Adaptive evolution and regulatory changes 77 IV. Gene duplications, GRNs and diversification of form 77 V. Ontogeny, homology and the study of plant adaptation 78 VI. Case study 1: Symmetry and adaptation of floral form 79 VII. Case study 2: Organ fusion and adaptation of floral form 82 VIII. Conclusion 86Acknowledgements 87References 88