I just read this piece from the space.com website: “Are Earthlings from Mars?” The post begins this way:
It’s possible that the family tree of all life on Earth has its roots on Mars — and a new device could put that theory to the test in a few years, researchers say.
Researchers are developing an instrument that would search through samples of Martian dirt, isolating any genetic material from microbes that might be present — bugs that are living or that died relatively recently, within the last million years or so. Scientists could then use standard biochemical techniques to analyze any resulting genetic sequences, comparing them to what we find on Earth.
Sounds interesting, to say the least, but the MIT researcher working on the device already seems to sense it won’t solve anything when it comes to the panspermia issue. His frank admission: “[I]f we go to Mars and find life that’s related to us, we could have originated on Mars. Or if it started here, it could have been transferred to Mars.” So, in other words, if we find a genetic relationship, we haven’t found in which direction it worked. This is a classic panspermia dilemma. The same presumed mechanisms (e.g., meteorites, solar wind) that could have brought Martian microbes here to kickstart life on earth in the evolutionary model could just have well worked the other way.
But still, it’s a pretty interesting research trajectory.