Perspectives in Evo-Devo of the Vertebrate Brain
Résumé
The nervous system, and particularly the brain, is probably one of the most fascinating subjects for evolutionary biology. This chapter discusses the developmental mechanisms which, within a common Bauplan, allow for variations in brain anatomy. The authors identify several “nodes” at which, within a common Bauplan to build a vertebrate type of brain, developmental evolution can shape differences. These critical points include the control of early signaling systems, the tight regulation of proliferation, and the emergence of new progenitor types in the embryonic neuroepithelia. Many developmental studies show the involvement of signaling molecules in the patterning of the brain, but examples in which variations of these molecules actually lead to evolutionary diversification of vertebrate brains are rare. The chapter explains the comparative, or evo-devo, study of proliferation that can be dealt with at several levels. Finally, the chapter focuses on recent studies highlighting various means of modifying cis-regulation.