Life would face challenges on Mars today, but billions of years ago conditions might have been better.
Life may have started on Mars before arriving on Earth, a major scientific conference has heard.
New research supports an idea that the Red Planet was a better place to kick-start biology billions of years ago than the early Earth was.
The evidence is based on how the first molecules necessary for life were assembled.
"The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock”
Details of the theory were outlined by Prof Steven Benner at the Goldschmidt Meeting in Florence, Italy.
Scientists have long wondered how atoms first came together to make up the three crucial molecular components of living organisms: RNA, DNA and proteins.
The molecules that combined to form genetic material are far more complex than the primordial "pre-biotic" soup of organic (carbon-based) chemicals thought to have existed on the Earth more than three billion years ago, and RNA (ribonucleic acid) is thought to have been the first of them to appear.
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