If they have protein in their samples and find amino acids of both chirality, then get exited. If they only find the chirality naturally occurring in earth based life: forgetaboutit
If our aminoacids came from space, you would sort of expect them to be in "incoming" organisms also.
Bioinformatics might be able to bring further light into this problem. If they do find DNA/RNA then they can tell when terrestrial life and whatever this is parted ways. If this root can be pinpointed after known mutations from fossil records, then this must be terrestrial life.
Bioinformatics might be able to bring further light into this problem. If they do find DNA/RNA then they can tell when terrestrial life and whatever this is parted ways. If this root can be pinpointed after known mutations from fossil records, then this must be terrestrial life.