Armin Moczek is an evolutionary developmental biologist broadly interested in understanding why and how developmental evolution has unfolded the way it has, why and how novel complex traits originated when they did, and the future of developmental evolution on a rapidly changing planet. In all of this he pays particular attention to the nature of gene regulatory networks in development, the mechanisms and consequences of developmental plasticity, and the roles of developmental symbioses and niche construction in evolutionary innovation.
In the context of the Agency in Living Systems project, the Moczek research group utilizes insects, in particular beetles, to identify the features of gene regulatory networks that allow novel traits to emerge, integrate in development, and persist within phylogenetically established developmental contexts. By comparing cases where innovation is enabled through the re-use of pre-existing networks to, alternatively, networks newly assembled “from scratch” their work also seeks to address whether different types of gene regulatory networks provide alternate routes to novel, adaptive traits and to the developmental resilience required to accommodate them. These investigations generate important new insights into one of the most foundational questions in evolutionary biology – how do novel complex traits come into existence – by clarifying how gene regulatory networks may serve as sources of causal agency in the initiation of novel traits and trait functions.
Wing serial homologues and the diversification of insect outgrowths: insights from the pupae of scarab beetles (2021)
Modification of serially homologous structures is a common avenue towards functional innovation in developmental evolution, yet ancestral affinities among serial homologues may be obscured as structure-specific modifications accumulate over time. We sought to assess the degree of homology to wings of three types of body wall projections commonly observed in scarab beetles: (i) the dorsomedial support structures found on the second and third thoracic segments of pupae, (ii) the abdominal support structures found bilaterally in most abdominal segments of pupae, and (iii) the pro-thoracic horns which depending on species and sex may be restricted to pupae or also found in adults. We functionally investigated 14 genes within, as well as two genes outside, the canonical wing gene regulatory net-work to compare and contrast their role in the formation of each of the three presumed wing serial homologues. We found 11 of 14 wing genes to be functionally required for the proper formation of lateral and dorsal support structures, respectively, and nine for the formation of prothoracic horns.At the same time, we document multiple instances of divergence in gene function across our focal structures. Collectively, our results support the hypothesis that dorsal and lateral support structures as well as prothoracic horns share a developmental origin with insect wings. Our findings suggest that the morphological and underlying gene regulatory diversification of wing serial homologues across species, life stages and segments has contributed significantly to the extraordinary diversity of arthropod appendages and outgrowths.
Descent with modification is the foundational framework of all of evolution. Yet evolutionary novelties are defined as lacking affinities to structures that already existed in the ancestral state, i.e. to somehow emerge in the absence of homology. We posit that reconciling both perspectives necessitates the existence of a type of innovation gradient that allows descent with modification to seed the initiation of a novel trait, which once in existence can then diversify into its variant forms. Recent work on diverse, textbook examples of morphological novelties illustrate the value of the innovation gradient concept. Innovations as profound and diverse as insect wings, beetle horns, and treehopper helmets derive from homologous source tissues instructed in their development by homologous gene regulatory networks. Yet rather than rendering these traits no longer novel, we posit that discoveries such as these call for a reassessment of the usefulness of defining evolutionary novelty as necessitating the absence of homology. Instead, we need to redirect our attention to how ancestral homologies scaffold and bias the innovation gradient to facilitate hotspots of innovation in some places, and deep conservation elsewhere.
Developmental bias in horned dung beetles and its contributions to innovation, adaptation, and resilience (2019)
Developmental processes transduce diverse influences during phenotype formation, thereby biasing and structuring amount and type of phenotypic variation available for evolutionary processes to act on. The causes, extent, and consequences of this bias are subject to significant debate. Here we explore the role of developmental bias in contributing to organisms’ ability to innovate, to adapt to novel or stressful conditions, and to generate well integrated, resilient phenotypes in the face of perturbations.