Abstracts

2002 Developmental Biology  
Evolutionary developmental biology has presently reached a level of maturity wherein it can offer evidence as to how major changes in body plans have occurred. These insights can be integrated into the teaching of evolution to undergraduate and other lay audiences. Moreover, in such a presentation, examples form evo-devo can illustrate that biologists (a) have excellent evidence for evolution at the molecular level, (b) have hypotheses as to the causal mechanisms of morphological change, and
more » ... can provide plausible explanations for macroevolution. Moreover, in such a presentation to lay audiences, one does not need the mathematics of population genetics to provide mechanisms for evolution. In such a talk, one can mention homologies (of Pax6 and Hox), descent with modification (FGF and Hox genes), the roles of hereditary changes these genes' expression patterns and structures (limb development in snakes and insects), and the idea that analogous structures (e.g., human eyes and fly eyes) can be generated form homologous sets of genetic instructions. The lecture will be one such presentation. Getting the Point: Using PowerPoint for Teaching and Research. The developmental constraint is one of important factors that could limit possible evolutionary trajectories. The conservation of convergently evolved developmental program under different selection regimes could be interpreted as an indication of developmental constraint. Polyembryony in parasitic wasps evolved four independent times in families Encyrtidae, Braconidae, Driiinidae, and Platygasteridae. Our goal is to understand whether independent evolution of polyembryony is associated with the reuse of the same regulatory cascades or whether multiple regulatory pathways can lead to the same result? We are characterizing development of the polyembryonic braconid, Macrocentrus grandii, and comparing its development with our model polyembryonic wasp, encyrtid, Copidosoma floridanum. We find changes in Macrocentrus ovarial structure, proliferative phase of development, and morphogenetic patterning relative to Copidosoma. However, analysis of germ line development using the Macrocentrus vasa homolog indicates conservation of the germ line specification in polyembryonic development. 23. Proliferation during Polyembryonic Development. Laura S. and †University of Georgia, Athens, Georgia. Copidosoma floridanum is a polyembryonic parasitoid wasp that produces two castes during development from a single egg. Polyembryonic development proceeds by a process of cellular proliferation resulting in a single brood containing approximately 950 reproductive larvae that develop into adult wasps and 50 precocious larvae that function as soldiers. We examined how the single egg proliferates and responds to environmental factors to produce two castes in C. floridanum. Our results indicate that the earliest stages of wasp morulae have the highest proliferative capacity and produce both larval castes. The older wasp morulae produced significantly fewer larvae and could produce one caste or
doi:10.1006/dbio.2002.0723 fatcat:e3pkdylpcne6hhskwgzdtl2vuu