An Integrative Developmental Biology

An active interchange of ideas has begun to develop in recent years between developmental biologists and physiologists interested in the development of complex traits. It is clear that this is a time of exciting challenges for both fields, challenges that present opportunities for significant mutual illumination between them. Members of both fields met at a workshop held in Arlington, Virginia, on November 15-16, 2004. This report presents the synthesis of ideas that emerged from a broad-ranging discussion that resulted. Developmental biologists have, for many years, focused their efforts to understand ontogeny by selecting a few model organisms that are genetically tractable, and that are appropriate to the study of fundamental processes of development at the genetic, molecular and cellular levels. These efforts have led to a detailed understanding of the genetic mechanisms that are involved in the control of developmental events. Many of the findings that have emerged from this work have proven remarkably transferable among the models studied. Developmental biologists have relied on model systems with relatively little but controllable genetic variation. Consequently they have typically not studied the way developmental mechanisms differ among species, nor the variance in mechanism among individuals due to normal variation in genetic and environmental factors. Some developmental biologists have recently begun to expand their studies to include non-model species for understanding aspects of developmental processes not reflected in the models. Still others are interested in illuminating the breadth or limitations of the generalizations discovered in the model systems. Recent developments in genomic approaches have facilitated this move away from the few genetically tractable model systems. Animal physiologists, by contrast, have been reluctant to adopt the use of a relatively small number of model species. This is in part because the physiological principles that bind the subscience cohesively , such as regulation and control of the functions required for normal operation, are known to differ between species. Thus, animal physiologists have employed a broad array of study systems, each selected for its suitability to address a specific physiological mechanism. Interestingly, some investigators have recently advocated the adoption of model systems that are genetically tractable as a means to approach questions about the genetics and evolution of physiological mechanisms, and as a means to leverage financial support of genomic approaches, which remain costly. A deep understanding of the development and function of complex phenotypes will require integration of the cellular and organ-level approaches of developmental …