Heritable variation in gene expression is raw material for the evolution of development, yet almost nothing is known about the distribution of such variation in nature. This proposal outlines a plan to estimate the structure of heritable variation in developmental gene expression in a natural population of purple sea urchins, a model system for developmental biology. Through the use of quantitative genetic techniques, the pattern of heritable variation in the abundance of gene products will be estimated for 120 genes at each of four stages in embryonic development. The resulting estimates will help answer several outstanding questions: How much heritable variation exists for early developmental gene expression? What is the timecourse of genetic variation and covariation? How do maternal effects influence variation in gene expression? Finally, how do networks of regulatory gene interactions influence the architecture of developmental variation, and hence the possibilities for developmental evolution?
This research will contribute to the synthesis of evolutionary and developmental biology, validate a new approach to studying heritable trait variation, and introduce quantitative genetics into sea urchin research. In addition, a deeper understanding of the patterns of genetic correlations among developmental gene expression traits could have applications to animal breeding and medical association studies.
