A frozen cradle for Earth's first life

摘要

If you thought life evolved in bubbling hot springs, think again. Pieces of RNA have been made that can copy RNA strands longer than themselves, supporting the idea that the first life was based on self-replicating RNA, not DNA. What's more, they work best in the cold, hinting that life began on ice. RNA is a jack-of-all trades. Like DNA it can store genetic material, but it can also catalyse chemical reactions. For this reason, many believe it was the basis of the first life. If this was the case then those early organisms must have had an enzyme created out of RNA to copy their RNA genomes. But no known RNA enzyme can copy a stretch of RNA as long as itself, without which RNA organisms couldn't have survived for long.