The effects of genetic elements on human health are highly dependent both on other genes in the genome as well as external environmental influences. Understanding how functional biological systems arise from the integration of environmental and genetic information is a central research challenge that has implications for medicine, agriculture, and the response of our global ecology to a changing environment. In ants, environmental signals, including social interactions and nutrition, cause developing larvae to differentiate into distinct morphological castes as adults. These individuals cooperate to form a coherent social unit, analogous to the epigenetic processes of cell differentiation and cell signaling that underpin the development of unitary organisms. Caste development in ants provides an opportunity to understand how environmental information can induce alternative genetic programs at the level of an entire animal. Furthermore, the study of castes will allow us to understand how heterogeneous groups of individuals cooperate to produce functional collective behaviors, and the way that these groups can evolve. All of these topics are directly relevant to the genetic and cellular basis of human physiology and could greatly improve our understanding of human health. To identify and characterize the core mechanisms of caste development in ants, this proposal presents an integrative research program that spans multiple scales of biological organization: 1) The use of functional genetic manipulations and mutant libraries to study caste from a developmental perspective using highly controlled and replicated experimental methods. 2) The application of recent advances in population and comparative genomics to understand the genetic basis of caste evolution in natural ant populations and validation of results using laboratory experiments. 3) The generation of a large-scale database of caste morphology across both living and fossil ant species, and the application of these data to test specific predictions about how the mechanisms of caste development have constrained and facilitated caste evolution throughout the ants. This research will provide some of the first mechanistic insights into caste development and evolution, and will promote a unified understanding of epigenetics, phenotypic plasticity, and emergent properties in biological systems.
The goal of the proposed research is to produce an integrative study of the epigenetic process of caste development in ants. The research will advance our understanding of this cell-type-like differentiation process using three complementary scientific approaches: laboratory, field, and museum studies. Caste is one of the most exaggerated and robust examples of phenotypic plasticity in nature, and this research important advances in understanding the mechanisms and evolution of animal development.
