Eventually, humans will set foot on Mars, carrying the cocktail of microbes that live on and inside our bodies with them. These microbes too will likely adapt, mutate, and change. And we can learn from them too. They may even make life on Mars more tolerable for those who go there, since the unique genomes adapting to the Martian environment could be sequenced, transmitted back to Earth for further characterisation, and then utilised for therapeutics and research on both planets.
Given all the planned Martian missions, we are at the shore’s edge of new era of inter-planetary biology, where we will learn about adaptations of an organism on one planet and apply them to another. The lessons of evolution and genetic adaptations are inscribed in the DNA of every organism, and the Martian environment will be no different. Mars will write its new selection pressures on organisms that we will see when we sequence them, opening an entirely new catalogue of evolutionary literature.
This is not just for idle curiosity, but rather a duty for our species to protect and preserve all other species. Only humans understand extinction, and thus only humans can prevent it, which applies today as well as it does in billions of years, when the Earth’s oceans begin to boil and the planet becomes too hot for life. Our inevitable violation of planetary protection will occur when we start to head off towards other stars, but in that case, we will have no choice. Eventually, careful and responsible forward contamination is the only way to preserve life, and it is a leap we must begin to make over the next 500 years.
* Christopher Mason is a professor of genomics, physiology, and biophysics at Weill Cornell Medicine, Cornell University. He researches the molecular and genetic effects of long-term human spaceflight on Nasa and other astronauts, as well as the design of new cell types for cancer therapy, and is the author of The Next 500 Years: Engineering Life to Reach New Worlds.
If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.