Hey, it’s all about evolution. This is the session labeled as being about evo-devo, but I’ve been thinking about evolution in all of the talks, so I guess here we’re just making it more explicit.
08:00-09:30 Session 5: Evolution of Development (Chair: Elaine Seaver [Univ. Hawaii])
Â Â 08:00-08:30 Brad Davidson (Univ. of Arizona) “Microenvironmental cues refine inductive signaling during Ciona intestinalis heart development”
Ciona heart is a simple system: only two precursors! Inductive response to FGF is dependent on cell adhesion. Cool confocal work on cell behavior.
Â Â 08:30-08:50 Yale Passamanack (Postdoc, Univ. Hawaii) “Early photoreceptor development in brachiopods, and the evolution of morphological complexity”
Â Â 08:50-09:10 Neva .P. Meyer (Postdoc, Univ. Hawaii) “Central nervous system development in the annelid Capitella teleta”
Simple nervous system, lovely images of serotonin staining. They’ve got a small brain produced by cells dividing on surface, then migrating inward by bottle cell formation. Anterior epithelium becomes multiple-layered; internalized cells do not divide further. Pro neural genes expressed — similar to insects. Knockdown of achaete-scute homolog causes loss of synaptotagmin, blocks brain formation. Â Neurogenesis in Capitella resembles myriapod dev.
I think I’m going to have to talk about Capitella in my fall neuro course.
Â Â 09:10-09:30 Andy Ransick (Faculty, Cal Tech) “Developmental mechanisms accompanying the evolution of echinoid larval mesoderm”
Echinoids have a unique pattern of early divisions. What follows is an Eric Davidson style analysis of molecular circuitry. There is a kind of double negative logic to activation of this module, with parts of the network dedicated to stabilizing output.
Micromeres are an evolutionary novelty that creates a new signalling center. Ransack discusses the regulatory module that is active here.