Annelid Distal-less/Dlx duplications reveal varied post-duplication fates.

Background: Dlx (Distal-less) genes have various developmental roles and are widespread throughout the animal kingdom, usually occurring as single copy genes in non-chordates and as multiple copies in most chordate genomes. While the genomic arrangement and function of these genes is well known in vertebrates and arthropods, information about Dlx genes in other organisms is scarce. We investigate the presence of Dlx genes in several annelid species and examine Dlx gene expression in the polychaete Pomatoceros lamarckii.

Features of the ancestral bilaterian inferred from Platynereis dumerilii ParaHox genes.

Background: The ParaHox gene cluster is the evolutionary sister to the Hox cluster. Whilst the role of the Hox cluster in patterning the anterior-posterior axis of bilaterian animals is well established, and the organisation of vertebrate Hox clusters is intimately linked to gene regulation, much less is known about the more recently discovered ParaHox cluster. ParaHox gene clustering, and its relationship to expression, has only been described in deuterostomes.

The molecular basis for the evolution of the metazoan bodyplan: extracellular matrix-mediated morphogenesis in marine demosponges.

Molecular data on development/differentiation and on comparative genomics allow insights into the genetic basis of the evolution of a bodyplan. Sponges (phylum Porifera) are animals that are the (still extant) stem group with the hypothetical Urmetazoa as the earliest common ancestor of all metazoans; they possess the basic features of the characteristic metazoan bodyplan also valid for the animals of the crown taxa. Here we describe three homeobox genes from the demosponge Suberites domuncula whose deduced proteins (HOXa1_SUBDO, HOXb1_SUBDO, HOXc1_SUBDO) are to be grouped with the Antennapedia class of homeoproteins (subclasses TIx-Hox11 and NK-2).