The non-bilaterian animal lineages Porifera, Placozoa, Ctenophora, Cnidaria are pivotal for our understanding of early animal evolution and diversification, and here I will present three snapshots of research in my group on comparative (phylo)genomics of these lineages:

1) Despite more than a decade of intense effort, the deep phylogenetic relationships of non-bilaterian animals remain problematic and highly controversial, although essential for understanding the origin and early evolution of key-animal traits, such as the nervous systemanimal. I will review the current status of non-bilaterian phylogenomics and provide corroborative evidence from (primary) sequence-independent data for currently the best working hypothesis of their relationships;

2) According to molecular clock estimates animal life originated and diversified about 800 My ago before the Cryogenian in a low-oxygen world. However, it is still debated how much oxygen was needed for animals to evolve. To address this issue, we used sponges as a proxy to suggest that early animals probably only needed very little oxygen and that these animals may not have sensed oxygen in a way bilaterians do;

3) Placozoans are an enigmatic non-bilaterian phylum with only a single valid species described for 135 years. They arguably show the simplest animal morphology, which is identical among isolates collected worldwide, despite an apparently sizeable genetic diversity within the phylum. We used comparative genomics for a deeper appreciation of the structure and causes of the deeply diverging lineages in the Placozoa and describe, for the first time in animals, a new genus and a new species purely based on genomic data