Yet (as I said) the galaxy existed for 9 Gyr pre-solar and the solar nebula included debris from earlier planetary systems, which were incorporated into the Earth and other planets. Does this imply RNA panspermia, Joyce asked – yes, if the earlier evolution had only proceeded as far as RNA and not the more stable DNA.
Antonio Lazcano as chair said: ‘time is not the problem’, as all evolutionary steps via RNA to organisms using the DNA-ribosome-enzyme system are still needed. Yes, would be my answer, but ‘the Earth is not the site’. We might assume an Earth-like planet, but do need to retain a wider perspective, and not assume that we can investigate early Earth or early Mars rocks and chemical complements are devoid of biomaterials. Rather, we might look at comets as more likely to contain pre-solar remnants of biomatter with DNA fragments, at least.
David Deamer from the Panel echoed this point in saying he believes the RNA-world environment is much more complex than we are trying to simulate.