Editorial Evolutionary Developmental Genomics: At the 2008 meeting of the European Society for Evolutionary Developmental Biology The second meeting of the European Society for Evolutionary Developmental Biology (EED) was held in Ghent (Belgium) between the 29th July and 1st August, 2008. Within this large, wide-ranging conference we organised a symposium on Evolutionary Develop- mental Genomics. Here we provide a brief overview of the symposium and put the three contributions in this issue of Genomics from Sebastian Shimeld, Antony Durston and Ron Parchem, who were speakers in the symposium, into context. The principle stimulus for the symposium was the incontrovertible fact that we are living through an era of a huge, ever expanding quantity of DNA sequence data, that is having a massive impact on so much of biology, Evolutionary Developmental Biology included. This is simply illustrated by the data filed with Genbank at the time of the symposium (release 166, June 2008) representing92,008,611,867 bp. Now, one year later (release 172, June 2009), the figure stands at 105,277,306,080 bp, a staggering increase of 13,268,694,213 bp, made all the more stunning when one considers that this represents the traditional divisions of Genbank and does not include the Whole Genome Shotgun sequences. Alongside various whole-genome sequences and expressed sequence tag (EST) projects we now have a treasure-trove of information with which to understand and investigate animal evolution from a much more comprehensive point of view. Themes running through this symposium can be broadly summar- ized as, (1) the need to handle all of this data and navigate carefully through it, (2) assembly of complete catalogues of developmental genes and gene families, illustrating the prevalence of gene gains and losses in genome and network evolution, (3) the importance of non- coding sequences, and (4) the crucial links between genome or gene organization and developmental mechanisms. What follows is a brief outline of each talk besides the three covered in greater detail in the accompanying reviews. Silvan Oulion (CNRS Gif-sur-Yvette, France) described the Hox gene clusters of the dogfish, Scyliorhinus canicula, following BAC clone and EST sequencing, clarifying our understanding of patterns of gene loss within the vertebrate Hox clusters, and revealing extensive alternative splicing and sharing of untranslated exons between multiple genes. This last discovery may account for a form of constraint on Hox clustering. Intriguingly the dogfish may have lost or severely degenerated its HoxC cluster. Simone Kienle (Max Planck Institute for Developmental Biology, Germany) presented the use of second-generation sequencing to obtain the whole genome (169 Mb) of a Polish strain of the nematode, Pristionchus pacificus, to detect SNPs relative to a Californian strain. These SNPs are now being mapped to loci involved with the phenotypic differences between these two strains with the aid of recombinant inbred lines from California/Polish crosses. This repre- sents a powerful approach to determine the genetic basis underlying phenotypic diversity in closely related organisms. Barbara Negre (University of Cambridge, UK) outlined the evolution of the Achaete-Scute proneural gene cluster in insects, utilizing the improving availability of insect whole-genome sequences. This diversity of available genomes now permits the detection of conserved regulatory elements, particularly amongst the Drosophilids, as well as revealing that independent expansions of the cluster have occurred in different lineages, which possibly relate to functional and morphological diversification [1]. Elena Simionato (CNRS Gif-sur-Yvette, France) presented a classification of the bHLH transcription factors of animals, from a phylogenetically broad sample of whole genomes. There were already 10–14 families of bHLH genes before the origin of the sponges, early in animal evolution, and there was then a large expansion of families before the origin of the Cnidaria [2]. These genes often have prominent roles in neurogenesis, such as the Atonal/Neurogenin genes of bilaterians like Drosophila and vertebrates. Sponges, despite lacking a nervous system, possess a gene that looks like a precursor to the Atonal/Neurogenin families, which intriguingly is co-expressed (in the so-called globular cells) with other genes orthologous to bilaterian neuronal genes ([3] and [4]); an example of a morphological novelty (neurons) evolving on pre-existing molecular networks and developmental regulators. Michael Schubert (ENS de Lyon, France) detailed the evolution of retinoic acid (RA) signalling in development by comparison of animal genome sequences and showed that RA signalling components were certainly in place by the origin of the deuterostomes, but possibly even earlier in animal evolution, at the origin of the Bilateria [5]. Moreover, the recently completed amphioxus genome facilitated the isolation of a large number of potential RA-target genes, which were then tested for direct regulation by RA signalling with combinations of treatments with RA and puromycin (to inhibit translation). This approach revealed a selection of direct targets during gastrulation, which include different Hox genes. David Ferrier (University of St Andrews, UK) dealt with the importance of analysing genomes that are less derived than many traditional model systems in order to reconstruct ancestral states that are the starting points for major transitions in animal evolution, such as the origin of the chordates and Bilateria. Amphioxus is one such suitable genome that has retained all of the homeobox gene families that were present in the last common chordate ancestor, whilst other chordate lineages (including humans) have lost several families. The supposedly prototypical chordate Hox cluster of amphioxus is now also known to contain 15 Hox genes, the Genomics 95 (2010) 247–249 0888-7543/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.ygeno.2009.07.001 Contents lists available at ScienceDirect Genomics journal homepage: www.elsevier.com/locate/ygeno