Meeting Abstract

128.4  Tuesday, Jan. 7 14:15  Recapitulating Heterochrony in Ascidian Development COLANTUONO, B*; IRVINE, S; University of Rhode Island bcolantuono5735@my.uri.edu

Solitary ascidian life history can be thought of as separating Romer’s somatic and visceral organ systems. Embryonic and larval development are dominated by somatic systems (sensory and locomotory), while at metamorphosis the somatic systems are largely replaced by the visceral (digestive and reproductive). In many colonial ascidians however, somatic and visceral organs develop together in the embryo and larva. We are examining the expression of candidate genes expressed at the larva-juvenile transition in the solitary ascidian Ciona intestinalis and the colonial ascidian Didemnum vixellum. In addition, we have constructed an inducible expression vector which is used to express putative “metamorphosis genes” at earlier stages in C. intestinalis to determine whether gene batteries for visceral development can be activated during embryonic development in the solitary ascidian. These experiments are aimed at recapitulating the evolutionary changes that may be involved in the heterochrony seen in the type of life history apparently derived multiple times from solitary ancestors.