Eco-Evo--Devo and the Origin and Elaboration of a Major Evolutionary Transition

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A long-term goal of my research program is to understand the developmental genetic mechanisms underlying both the origins and elaboration of biological complexity. The history of life is marked by several major evolutionary transitions in individuality, which occur when individual organisms unite to form a higher-level individual. Examples of such major transitions include the evolution of obligate endosymbiosis - in which an unrelated host and endosymbiont unite to form a single individual, the evolution of multicellularity - in which unicellular protists unite to form multicellular organisms, and the evolution of eusociality - in which solitary insects unite to form social insect colonies. Such transitions are thought to have driven major increases in biological complexity over the course of evolution because they result in higher-level individuals with a division of labor between their constituent parts. Although biologists have begun identifying evolutionary principles shared across major transitions in individuality, little is known about the developmental genetic mechanisms that facilitated their origin and elaboration. Over the last 6 years, my lab has gained significant momentum to capitalize on several recent discoveries to uncover the developmental genetic mechanisms underlying the origin and elaboration of the transition to eusociality in ants. Ants are one of the most ecologically dominant and evolutionarily successful group of organisms on our planet. Similar to a multicellular organism with its division of labor between germline and somatic cells, an ant colony is equivalent to a `superorganism' with a reproductive division of labor between the fertile queen (the germline) and her non-reproductive workers (soma). Understanding the origin and evolution of novel castes within ant colonies may reveal general principles underlying origin and evolution of novel cell types within multicellular organisms. We will begin to uncover the developmental genetic mechanisms underlying the origin and elaboration of the transition to eusociality in ants through three research objectives: Objective 1 will test the hypothesis that programed cell death plays a key role in the origin of a novel winged queen and wingless worker caste. Objective 2 will test the hypothesis that DNA damage response pathway plays a role in elaborating the reproductive asymmetry between the queen and worker caste. Objective 3 will test the hypothesis that the wing rudiments were re-purposed into developmental signaling centers that elaborate the worker caste into a complex worker caste system. My research program has the potential to reveal that the mechanisms involved in the origin of biological complexity also function in its elaboration and will potentially reveal general mechanistic principles shared across different major transitions in individuality. My research program will further serve NSE in Canada by training 7 HQP over the course of the following five years.