Chapter 20 - Variation and Developmental Biology: Prospects for the Future

Abstract

This chapter argues that many of the biggest questions for developmental biology still remain unanswered. Some of these questions explicitly concern variation. A new incorporation of population thinking into developmental biology will need to be achieved. The modern era of developmental biology has its roots in comparative morphology, the experimental embryology of Roux, and the genetics of Morgan, and as such represents a synthesis of several disparate disciplines. This chapter suggests that the synthesis of modern developmental biology has remained essentially typological in outlook, despite operating in parallel with the fundamentally populational neo-Darwinian synthesis. It also suggests several questions, each relating to variation, and how a populational viewpoint will need to be accommodated. A key factor underlying the last 50 years of progress in developmental biology has been the emergence of a few, key “model organisms.” Among these are the venerable fruit fly Drosophila melanogaster (“the Fly”), the nematode Caenorhabditis elegans (“the Worm”), the anuran amphibian Xenopus laevis (“the Frog”), the chicken Gallus gallus, the mouse Mus musculus, as well as more recent additions such as the mustard weed Arabidopsis thaliana and the zebrafish Danio rerio. The use of model organisms has greatly facilitated advances through the resulting concentration of resources. Perhaps the most dramatic of resources is the availability of sequence data for the complete or nearly complete genomes of each of these models.