That's why they [viruses] are not in the tree of life. They don't relate in a very direct way. ...[T]he tree of life now is not only about ribosomes.… - Nick Lane

It would be a little disappointing if we didn't even find bacteria in our own solar system. I would be rather surprised to find what I would describe as large, morphologically complex life. ...It only arose once on earth. That doesn't necessarily mean that it's improbable... but it does raise some interesting questions about why, and... I think we can apply principles to it, and those principles effectively are why do bacteria and , as assistive groups to the bacteria... They're biochemically very complex. They're genetically very complex. They're kind of structured in a different way where they have large, complex metagenomes, but... I doubt very much that we'll ever find anything of the [morphological] level of complexity of a flea, composed of bacterial cells.

The DNA code is inert... stored safely... For daily use the cell relies on disposable photocopies... made of RNA... composed of similar building blocks... spun out on a single strand rather than the... double helix.

[N]o bacteria coat their DNA with s: their DNA is naked. The histones not only protect eukaryotic DNA from chemical attack, but also guard access to the genes.