Meeting Abstract

P1.4  Monday, Jan. 4  Homebox gene expression in developing zooids of the marine bryozoan Membranipora membranacea TEMKIN, M.H.**; BELL, P.; DIXON, E; St. Lawrence University; St. Lawrence University; St. Lawrence University mtemkin@stlawu.edu

Bryozoans are a phylum of colonial invertebrates that live in marine and freshwater habitats. Gymnolaemates represent the largest and most diverse group of extant bryozoans. Organization of body axes are established at three points during the life cycle of gymnolaemate bryozoans: as the fertilized egg develops into a larva, as the larva undergoes metamorphosis to form the ancestrula (the first member of each new colony), and as each asexually budded zooid develops within the colony. In animals, morphological structures along the body axes are specified according to the expression of the homeobox genes. A subclass of homeobox genes, called Hox genes, have been demonstrated to be responsible for organizing structures along the anteroposterior axis of the body. To begin to understand the role of homeobox gene expression in organizing the body axes of gymnolaemates, we characterized the mRNA and amino acid sequences of four homeobox genes from the marine gymnolaemate bryozoan Membranipora membranacea. These genes are the anterior Hox gene Deformed (Dfd), the central Hox gene Lox5, the posterior Hox gene Post-2, and the EHGBox gene Gbx2. Based on these mRNA sequences, we synthesized probes for visualizing gene expression in developing zooids using an in situ hybridization protocol. Here we present data on the expression of these four homeobox genes during the development of zooids in M. membranacea colonies.