From my arm chair viewpoint. I tend to like the idea of the Panspermia hypothesis. The idea that life evolved on Earth after incubating within a comet or asteroid. The implied imagery of this process just seems natural.

However, if that were the case. Chances are this would have likely happened multiple times. Perhaps some instances of such dying a quick death. Perhaps some instances of such still surviving to this day.

Also, perhaps life just evolved out of several swamps of primordial ooze. And there are many different variations alive today. Is there any evidence for this? Have we looked into DNA enough to see if this may have happened?

Would it be possible to test this by looking deep into the DNA of many different lifeforms on Earth? If this has happened then perhaps all life on Earth does not share a common ancestor after all.