I don't know much about microbiology, but I'm not sure that there will definitely be a huge difference between microbes on Earth and microbes on Mars. It could

I don't know much about microbiology, but I'm not sure that there will definitely be a huge difference between microbes on Earth and microbes on Mars. It could very well be that life was delivered to Earth from Mars at some point in the distant past. Perhaps the only places that microbial life exists on Mars are in places that have conditions similar to Earth. Underground water, etc.