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Our lab studies the gene regulatory networks underlying specification and correct development of chordate axial tissues.

Particular efforts are focused on investigating development and differentiation of the notochord.

The notochord is a distinctive feature of the chordate phylum and in vertebrates is the precursor of the backbone.

During chordate embryogenesis, the notochord plays a crucial role in patterning the central nervous system, axial muscles, liver, pancreas, heart, gut and so on, and in establishing left-right asymmetry.

Animals with a notochord first appeared about 550 million years ago, at the time of the Cambrian explosion.

Today, the most primitive living animals with a notochord are the urochordates, which are marine invertebrate chordates.

We study the evolutionary origins of the notochord and its flanking tissues in a urochordate, the ascidian Ciona intestinalis.

An adult Ciona and a schematic view of its anatomy.

ŠPassamaneck and Di Gregorio, Dev. Dyn., 233: 1-19, 2005.

The chordate blueprint in ~2500 cells. Panel A. Microphotograph of a Ciona larva. Dorsal is up, anterior on the left. Panel B. Drawing of the larval tissues, with the 40 notochord cells shown in red, the CNS (~350 cells) in blue, the endoderm (~500) in yellow, the mesenchyme (~900 cells), purple, and the epidermis (800 cells, covering trunk and tail) in green. Panel C. Drawing of the muscle cells flanking the notochord (18 per side).

ŠPassamaneck and Di Gregorio, Dev. Dyn., 233: 1-19, 2005.

There are several good reasons for using Ciona intestinalis as an experimental system: for instance, the genome has been sequenced and is publicly available together with a wide collection of ESTs and expression data; the embryonic development is extremely fast, the embryos are transparent and are available almost year-round and transgenic experiments can be carried out in a surprisingly short amount of time.