This lab focuses on the emerging field of evolutionary genomics. A vast amount of whole-genome sequence information is rapidly becoming available for a variety of metazoans. I plan to use this information to determine the gene regulatory networks underlying formation and specification of chordate axial tissues.

Particular efforts are focused on the gene regulation networks governing the specification 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 and gut. The 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.

There are several good reasons for using Ciona intestinalis as an experimental system: for instance, the genome has just 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.

We are currently preparing a collection of minimal notochord-specific cis-regulatory elements, from Ciona intestinalis. We plan to use the cis-regulatory elements isolated from Ciona to reconstruct, using appropriate computational methods, the minimum genetic "blueprint" responsible for notochord formation in vertebrates. Our long-term goals include using this strategy to scan non-chordate genomes (C. elegans, Drosophila, etc.) in order to gain insights into the molecular mechanisms that first gave rise to the notochord.

Our lab also focuses on the role played by T-box transcription factors in ascidian development, since these genes have been shown to be crucial for tissue-specification in different vertebrates.

Keywords:
ascidian, Ciona, notochord, muscle, CNS, chordate origins

Email Address:
and2015@med.cornell.edu