ASCIDIAN EMBRYOGENESIS AND THE ORIGINS OF THE CHORDATE BODY PLAN

For more than a century, ascidians have been a widely used system for classic embryological studies. Ascidians possess simple, well-defined cell-lineages, compact genomes, rapid development and world-wide distr ibution. Transgenic DNA can be introduced into developing embryos usin g simple electroporation methods. The ascidian larva represents the mo st simplified chordate body plan and provides a useful model for study ing the molecular pathways underlying the morphogenesis and differenti ation of the notochord and neural tube.