Ctenophores: an evolutionary-developmental perspective
Abstract
Ctenophores are non-bilaterian metazoans of uncertain
phylogenetic position, some recent studies placing them as
sister-group to all other animals whereas others suggest this
placement is artefactual and ctenophores are more closely
allied with cnidarians and bilaterians, with which they share
nerve cells, muscles and gut. Available information about
developmental genes and their expression and function in
ctenophores is reviewed. These data not only unveil some
conserved aspects of molecular developmental mechanisms
with other basal metazoan lineages, but also can be expected
to enlighten the genomic and molecular bases of the evolution
of ctenophore-specific traits, including their unique embryonic
development, complex anatomy and high cell type diversity.