Advanced orthology clustering of bilaterian and non-bilaterian sequences identifies 157 bilaterian-specific genes which are linked to key morphological features of this animal group.

Molecular profiling of annelid myocytes reveals that the last common protostome-deuterostome ancestor already possessed a dual musculature, with visceral smooth muscles ensuring digestion and somatic striated muscles ensuring locomotion.

The foundations of genomic complexity in multicellular animals have deep roots in their unicellular prehistory, both in terms of innovations in gene content, as well as the evolutionary dynamics of genome architecture.

Ancient animal Dicer used its helicase domain to couple the detection of foreign double-stranded RNA to efficient ATP hydrolysis and antiviral defense, but this function declined before the advent of deuterostomes and vertebrates.

The animal phylogeny of glutamate receptors indicates that vertebrate types do not account for all receptor classes originated during evolution, neither are they the pinnacle of a linear evolutive process.

Evolutionary reconstruction of the ecdysis pathway shows that its major elements are present in the majority of metazoans, providing evidence that they originated much earlier than currently assumed.

Discovery of new taxon of Saccorhytida suggests that the ground pattern of Ecdysozoa may not be elongated vermiform instead sac-like in shape.

Cuttlefish embryos reveal that cephalopod mollusks evolved specialized arms and tentacles by activating the same genetic circuits that control development of limbs in arthropods and vertebrates.

Expression patterns and biophysical properties of acid-sensing ion channels in numerous bilaterian animals offer insight into the deployment of ion channels by the evolving nervous system in complex animals.

The recently characterized opsin group of xenopsins is likely a major player in animal eye evolution and may have been present in an ancient, highly plastic eye photoreceptor cell type.