There are so many fascinating possibilities.

1) DNA based life with genetic overlap (potentially indicating that Mars life seeded earth life, or vs.vs).

2) DNA based life with no genetic overlap (possibly indicating original life on mars, or a common seed source for Earth and Mars)

3) Radical, non DNA based life (indicating original life on mars)

4) E. coli (indicating that NASA needs to fire their sterilization team).

I'm sure there are more fascinating possibilities that I'm not aware of!

DNA with different chirality (would likely prove distinct origins better than genetic overlap, if life was seeded from the same origin billions of years ago there could be no overlap today, and some overlap doesn't prove origin either since gene can develop independently even very specific mutations), proto-life - RNA world/self replicating proteins...

Both of those would likely be a "more interesting" thing to study.

The most boring part would likely be finding DNA life which is quite similar, I'm not sure it would point to any specific origin and if it's metabolically going to be quite similar to some life we can find on earth the overall new science from it might be fairly limited.

I hope it's the same, because if it's different it suggests our impending extinction. At least according to the logic of Bostrom's Great Filter.

Conversely wouldn’t imply the other life’s impending extinction symmetrically?

It would imply their extinction far into the future, after they've evolved to our level of intelligence, since our existence implies that the Great Filter exists ahead of us, not behind us

I don't think we know enough to say that for sure. If you are defining the great filter as the cause of the Fermi Paradox then it very well could be in our past. For example, the conditions or specific mutation that gave rise to multi-cellular life could be the great filter meaning that single celled life could be incredibly common but multicellular life might be almost entirely non-existent.

> the conditions or specific mutation that gave rise to multi-cellular life

Doubtful, given that we've been able to recreate multicellularity evolving in the lab. The initial jump to life, not so much.

We might want to say that our existence is some evidence that the filter is ahead of us but it could certainly be behind us (in which case the logic of the Great Filter doesn't apply for our civilization)

> Conversely wouldn’t imply the other life’s impending extinction symmetrically?

Yes and?

Just wanted to clarify that the implication arrow pointed both ways if it pointed one way, so I guess and that?