Grant: Discovery Grants Program - Individual

A central premise of evolutionary theory is that adaptive evolution requires natural selection acting on genetic variation. Over the past several years a vocal and growing group of evolutionary biologists have begun to express dissatisfaction with this view. This dissatisfaction has been most clearly enunciated in a call to replace the Modern Synthesis of evolutionary biology with an "Extended Evolutionary Synthesis". The rationale is that features of organismal development and niche construction, coupled with nongenetic forms of inheritance, lead to novel evolutionary processes that are not adequately captured by current evolutionary theory. The most radical claim is that such processes can even generate new variation that is adaptively biased, thereby enabling adaptation without natural selection. This claim represents a fundamental challenge to established evolutionary theory, and it is the most controversial element of the Extended Evolutionary Synthesis. One main reason for continued controversy on this topic is the lack of a precise description of how developmental processes and nongenetic inheritance can result in such novel evolutionary phenomena. We will develop a mathematical framework based on current evolutionary theory that is broad enough to encompass the key ideas put forward by proponents of the Extended Evolutionary Synthesis, and we will then use it to better determine the significance of these ideas. We will also develop detailed theory for three specific systems/questions, each of which represents a special case of the general framework: (i) the role of nongenetic inheritance and development (learning) in C. elegans, (ii) the role of nongenetic inheritance in the evolution of antibiotic resistance, and (iii) the role of nongenetic inheritance and development in aging and senescence.