Why do most species on earth have behavioral and physical changes over their life span (Figure 1)? Why are the most diverse and specious lineages those that undergo the bizarre process of complete metamorphosis? Why do males and females of many species look and behave radically different? These are the questions that fuel my research program. I am interested in how a single genome evolves to deal with the challenging and dynamic ecological demands of species, particularly when different life stages or sexes experience opposing selection pressures. When there is strong opposing selection between sexes, decoupling the expression of these genes removes these opposing pressures and allows sexual dimorphism to evolve. Likewise, when ecological demands change over the course of development, stage-specific gene and trait expression may evolve. I want to understand how ecology influences patterns of sex- and stage-specific expression and how these, in turn, alter traits that influence evolutionary outcomes. I am particularly interested in the role of expression when there are shifts to a novel environment with differing selection pressures or when there is gene flow between diverging populations.
At the core of my research program are two key concepts: the adaptive decoupling hypothesis and ecological speciation.
The adaptive decoupling hypothesis proposes that metamorphosis is an adaptation for optimizing expression of traits across life stages that experience opposing selection pressures.
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Ecological speciation is the separation of two populations into species due to differing ecological selection pressures. As populations divide reproductive barriers arise and speciation is finalized.
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Because genes with decoupled expression between stages or sexes may be less constrained by pleiotropy, they may contribute disproportionately to adaptation. Using trait outcomes due to these differences in expression, we can make predictions about the genes underlying adaptation to novel environments. To test these hypotheses, my research combines field work, lab experiments, genomic work, and bioinformatics. The intuitive ideas and integrative approach also provide an ideal training environment for undergraduate students. My future research program will focus on three main questions that undergraduates can use to develop guided independent research projects:
1) Do decoupled genes/traits play a disproportionately large role in adaptation to a new environment?
2) Do decoupled genes evolve faster than genes/traits expressed at multiple life stages/sexes?
3) Do decoupled genes/traits play a large role in completing speciation?
1) Do decoupled genes/traits play a disproportionately large role in adaptation to a new environment?
2) Do decoupled genes evolve faster than genes/traits expressed at multiple life stages/sexes?
3) Do decoupled genes/traits play a large role in completing speciation?