Problem:

Is it right to assume that the first living organisms on earth had a linear genome? I base this on the fact that linear macromolecules are clearly much more common in nature that circular ones. To be honest, I can't even think of any naturally-occurring circular macromolecules that aren't already a part of current living organisms.

Were the very first living organisms more likely to have linear genomes? If so, when during evolutionary time did circular chromosomes originate?

Please explain about the first living organisms on earth had a linear genome.