A genetic screen reveals that two predicted glycosyltransferases promote rosette development and prevent cell clumping in one of the closest living relatives of animals, the choanoflagellate S. rosetta.
Protein coding genes strongly support a sister group relationship between Placozoa and Cnidaria to the exclusion of Bilateria, contradicting previous phylogenies, which have likely been misled by pervasive compositional heterogeneity.
Sponges and ctenophores lack hypoxia-inducible factors, suggesting that the metazoan last common ancestor could have lived aerobically under severe hypoxia and did not need to regulate its transcription in response to oxygen availability.
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.
The complex chromatin-based genomic regulatory system controlling developmental gene expression in complex bilaterians predates the evolution of morphological complexity and may have been a prerequisite for the evolution of the first simple multicellular animals.
A catalytically dead paralog activates its cognate enzyme through an allosteric mechanism that combined structural and phylogenomic analysis indicates arose through acquisition of a dimerization domain, suggesting a general model for how complex allostery evolves.
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.