Eukaryotic nuclei define our difference from prokaryotes, and the use of histone proteins as DNA packing and genome regulation agents was a seminal invention. So profound was this innovation, that all eukaryotes continue to use it—all except dinoflagellates. We have shown that early in dinoflagellate evolution histones were largely abandoned and no longer play a role in bulk DNA packing. In its place, a new major nucleoprotein has been gained (DVNP), acquired from an algal virus. We are now studying genome architecture and management in this novel chomatin model, and the role and properties of DVNP. These studies are informing us of radical changes possible in nuclear organisation, and possible models for alternative chromatin systems that might be more broadly present in eukaryotes. 

Eukaryotes also possess genetic material in their mitochondria and plastids, relicts of the endosymbionts’ own genomes. The Waller lab is investigating evolutionary processes that continue to shape these organelle genomes also. In dinoflagellate mitochondria, again remarkable change is seen. Since diverging from their sister taxa Apicomplexa, these genomes have lost conventional translation start and stop signals, acquired a novel mRNA trans-splicing process, and the genomes have been massively amplified and become highly recombinatorial, despite encoding only three protein genes. Moreover, extensive RNA editing has been acquired in these mitochondria, and this process is even imposed upon recently gained dinoflagellate endosymbionts.