Meeting Abstract

S1.7  Monday, Jan. 4  Sympathoadrenal lineage in lampreys SAUKA-SPENGLER, T; Caltech spengler@caltech.edu

The neural crest is a multipotent stem cell-like population that forms a plethora of derivatives, including neurons and glia of the peripheral nervous system, craniofacial skeleton and melanocytes. Data compiled from vertebrate model organisms has led us to propose a multi-module GRN that underlies neural crest formation (NC GRN). We have used a basal vertebrate, the lamprey, to test, for the first time, the validity of the proposed NC GRN in a single vertebrate. Our results show that the majority of regulatory modules responsible for early steps in neural crest ontogeny are in place in the most basal vertebrate, and thus were fixed early in vertebrate evolution.  This includes regulatory mechanisms responsible for specification of bona fide neural crest specification and control of their migration.  While many neural crest derived cell types and structures also are conserved, lampreys lack several crest derivatives, most notably jaws and sympathetic nervous system.  Here, we asked whether the genes that regulate differentiation of the sympathoadrenal and other autonomic lineages in higher vertebrates were present or absent in lamprey to gain insight into the molecular basis and evolutionary history of this lineage.  The results suggest that evolution of the vertebrate autonomic nervous system may have involved cooption of genes present in other embryonic structures such as the notochord.