s are the crowning glory of life. ...[T]he rich variety of life is almost entirely attributable to the... variety of proteins. ...Perhaps the most im… - Nick Lane

What I would say with some degree of certainty from the example of life on earth, is that if you simply have a population of bacteria... the chances of it giving rise to the kind of morphological complexity... we see in eukariotic cells, and we do not see in bacteria, is remote... because bacteria and archaea, if you look at the amount of , they dwarf the genetic variation that we see in Eukaryotes. They have explored genetic sequence space to orders of magnitude greater that Eukaryotes did, and despite exploring all of that space, they haven't come up with morphological complexity. ...[T]hey did through an endosymbiosis. ...It's rare between prokaryotes, rare to the point that we know of one example of free-living bacteria with bacterial cells living inside it. We know of two other examples where, there's a for example, which has inside its own cells... some gamma protein bacteria, with beta protein bacteria living inside them. It's a little bit of a strange system and it's hard to know, again, can you generalize from this, because it's all inside a Russian doll?

[W]e can't agree among ourselves, as an origins of life community, what were the conditions... under which life arose on earth. ...Within the field itself, probably the leading candidate... would be terrestrial geothermal systems, starting with and powered by UV radiation. There's been a lot of rather beautiful chemistry... in a terrestrial environment in some kind of geothermal pool... and cyanide chemistry, it works well as chemistry. The problem I have with that is that it doesn't link up very well to biochemistry of cells. I'm a biochemist and I would like to see some continuity between and , and there's not much there, to me. That doesn't mean that it's wrong. It's just that... [I] would like to see some continuity.

The s were acquired by a eukaryotic cell that was already a fully fledged eukaryotic cell.