There probably isn't life on Mars, and if there is or was, that life would probably have come from the Earth (rather than the hypothesis of life from Mars populating the Earth).
The Viking Labeled Release Experiment and Life on MarsThus, organic compounds surviving this rugged digestion were detected in the soil. They were attributed to kerogen and coal refractory to the GCMS pyrolysis. Biological possibilities were discounted although viable microorganisms have been reported (23) within anthracite coal taken from deep underground. The purpose of the intensive digestion of the Antarctic #726 was not stated. One must wonder what variety of labile organic compounds were present prior to the digestion.
by Gilbert V. Levin