10-29-2016, 05:06 PM
(10-27-2016, 05:54 PM)stevebowers Wrote: I'd guess that about a third of all biospheres in the Terragen Sphere are still in the prebiotic stage, and many of those do not have a dominant form of replicating molecule but are chemical soups of metabolising molecules without genetics. The majority of biospheres do use replicating molecules, however; many will still be in the RNA-world stage, and some of these might be highly sophisticated. Others would use DNA (either dextro- or levo-), but this is not the only possibility by a long chalk.
Excellent response. That brings a couple other questions to mind. Is it possible that the 'alien' DNA in these other worlds could have an opposite chirality from terran DNA? Or would right-handed amino acids and left-handed nucleotides make them into something altogether different? And of these different replicating molecules you mentioned (TNA, GNA, PNA, etc), do any of them have advantages compared to DNA? In the prebiotic stage of a biosphere, are they any more likely to evolve and dominate over DNA?