An English chemist has found the hidden gateway to the RNA world, the chemical milieu from which the first forms of life are thought to have emerged on earth some 3.8 billion years ago.

He has solved a problem that for 20 years has thwarted researchers trying to understand the origin of life  how the building blocks of RNA, called nucleotides, could have spontaneously assembled themselves in the conditions of the primitive earth. The discovery, if correct, should set researchers on the right track to solving many other mysteries about the origin of life. It will also mean that for the first time a plausible explanation exists for how an information-carrying biological molecule could have emerged through natural processes from chemicals on the primitive earth.

The author, John D. Sutherland, a chemist at the University of Manchester, likened his work to a crossword puzzle in which doing the first clues makes the others easier. “Whether we’ve done one across is an open question,” he said. “Our worry is that it may not be right.”

Other researchers say they believe he has made a major advance in prebiotic chemistry, the study of the natural chemical reactions that preceded the first living cells. “It is precisely because this work opens up so many new directions for research that it will stand for years as one of the great advances in prebiotic chemistry,” Jack Szostak of the Massachusetts General Hospital wrote in a commentary in Nature, where the work is being published on Thursday.