Adaptation in Exploratory Processes

Applications are accepted now for anyone applying for Chinese Scholarship Council (CSC) funding only.
Applications already received by the initial 1 December deadline are now under consideration.

Organisms often respond to new challenges through ‘exploratory mechanisms’ (Gerhart & Kirschner, 1997), which are complex developmental systems that operate by generating variation (i.e. exploring possibilities), testing variants’ functionality, and selecting the best solutions, in an iterative developmental process that resembles adaptation by natural selection (a.k.a. ‘somatic selection’). For instance, the adaptive immune system generates antibodies and T cells with random variation, then internal selection multiplies and refines those that bind successfully to antigens, with a memory of effective molecules retained. Animal learning, the vertebrate nervous system, vascular and tracheal systems, and much collective animal behavior, operate on similar principles, generating novel functional responses in development.

Exploratory mechanisms enable rapid exploration of a large space of possibilities combined with feedback (e.g. reward/punishment) from the current environment that allows for information gain. Unlike genetic mutation, the novel phenotypic variation generated by such systems will typically be directional and adaptive.
Exploratory mechanisms are often associated with auxiliary processes with which they interact, and coevolve. For instance, adaptive immunity operates in concert with innate immunity, whilst learning interacts with perceptual systems. The existence of auxiliary systems allows organisms to produce a flexible plastic response to novel challenges but also to ‘outsource’ some reliably present adaptive responses to the innate auxiliary system, such that adaptation can evolve without compromising plasticity and exploratory potential. Hence, it is necessary to consider the exploratory-auxiliary system holistically to understand its evolution.
Standard conceptions of developmental plasticity (e.g. genetically specified reaction norms), and established mathematical approaches (e.g. population or quantitative genetics models), do not easily accommodate the exploratory aspects of biological systems. These theoretical limitations mean that science has a poor understanding of how complex organisms with rich forms of plasticity (e.g. vertebrates) evolve, and make it difficult for biologists to envisage how organisms can possess agency or impose direction on evolution. What is required is a new general means of investigating the bidirectional interaction between exploratory mechanisms and evolution.

Working in collaboration with a computer scientist at Southampton University (Dr Richard Watson), the student will be trained to devise computational models of adaptation in biological systems that exhibit exploratory behavior. The novelty of the approach stems from (1) the formal evolutionary analysis of exploratory mechanisms, (2) the simultaneous modelling of adaptive processes across two timescales (development and evolution), and (3) analyses of interactions between exploratory mechanisms and auxiliary systems. The models will test a series of hypotheses, including that: (i) exploratory mechanisms evolve in a qualitatively different manner from other forms of plasticity, (ii) exploratory mechanisms confer on biological systems a greater capacity to evolve, without themselves evolving much, and (iii) information gained from exploratory (developmental) mechanisms will often be ‘out-sourced’ to auxiliary (genetic) systems, allowing developmental events to impose direction on biological evolution. The models will evaluate the hypothesis that adaptation can originate during development, and shape evolutionary dynamics. The potential impact of the project goes beyond evolutionary biology, to influence immunology, psychology and neuroscience.