As I understand it DNA and RNA store their information in the form of certain amino acids. If other life uses amino acids in a similar fashion they may not use the same ones that life on Earth uses. Life here uses I believe 20 different amino acids and there are several hundred known.
So there's potential there I would imagine in regards to testing that hypothesis.
However what mainly bothers me with it is that it doesn't explain the origin of life and why Earth couldn't have original life begin on it.
Unless we can rule out that early Earth conditions would have been too inhospitable for life to start but was sufficient to sustain it I see no reason to think an extraterrestrial origin to Earth life is more likely.
> As I understand it DNA and RNA store their information in the form of certain amino acids.
Actually, information is stored as RNA, with DNA as long-term storage (mnemonic: RAM nucleic acid vs disk nucleic acid) and then amino acids are assembled into proteins (hardware) based on that information. Proteins only function as information storage in pathological cases like prions.
But yes, if 'alien' life used the same 20 amino acids, and especially if it has the same mapping from 64 nucleic acid triplets to 20 amino acids, then that's confirmation that it's actually just a earth microbe that escaped or was left behind.
Agreed that the extraterrestrial origin hypothesis doesn't actually explain anything. It just merely adds a factor to the Drake equation of how likely it is for life to get started.
So there's potential there I would imagine in regards to testing that hypothesis. However what mainly bothers me with it is that it doesn't explain the origin of life and why Earth couldn't have original life begin on it.
Unless we can rule out that early Earth conditions would have been too inhospitable for life to start but was sufficient to sustain it I see no reason to think an extraterrestrial origin to Earth life is more likely.