Models of Developmental Plasticity and Cell Growth

Abstract

In this note we discuss the following topics:

• 1. Epigenetics: How to alter your genes? This is evolution within a lifetime. Epigenetics is a relatively new scientific field; research only began in the mid nineties, and has only found traction in the wider scientific community in the last decade or so. We have long been told our genes are our destiny. But it is now thought a genotype’s expression (that is, its phenotype), can change during its lifetime by habit, lifestyle, even finances. What does this mean for our children? So we consider phenotype change:

  • (a) firstly in a stochastic setting, where we consider the expected value of the mean fitness;

  • (b) then we consider a Plastic Adaptive Response (PAR) in which the response to an environmental cue is initiated after a period of waiting;

  • (c) finally, we consider the steady-fitness states, when the phenotype is modelled on a continuous scale providing a structured variable to quantify the phenotype state.

• 2. Consider the steady-size distribution of an evolving cohort of cells and therein establish thresholds for growth or decay of the cohort.