Brian K. Hall
Professor EmeritusDepartment of Biology
Halifax, Nova Scotia
B3H 4JI, Canada
Marine Blology and Embryology; Germ Layer Specification, The Neural Crest. Professor Hall has researched and extensively written on bone and cartilage formation in developing vertebrate embryos. He is an active participant in the evolutionary developmental biology (EVO-DEVO) debate on the nature and mechanisms of animal body plan formation. Professor Hall has proposed that the neural crest tissue of vertebrates may be viewed as a fourth embryonic germ layer. As such, the neural crest - in Hall's view - plays a role equivalent to that of the endoderm, mesoderm, and ectoderm of bilaterian development and is a definitive feature of vertebrates (as hypothesized by Gans and Northcutt). As such, vertebrates are the only quadroblastic, rather than triploblastic bilaterian animals. In vertebrates the neural crest serves to integrate the somatic division (derived from ectoderm and mesoderm) and visceral division (derived from endoderm and mesoderm) together via a wide range novel vertebrate tissues (bone, cartilage, sympathetic nervous system, etc...). He has been associated with Dalhousie University since 1968. Since his retirement in 2007, he has been University Research Professor Emeritus and Emeritus Professor of Biology.