Molecules of pyrimidine, polycyclic aromatic hydrocarbons, have been identified in meteorites and could have survived long enough to migrate into interstellar dust clouds where they froze onto dust grains.
Scientists created a simulated environment where uracil was synthesized from pyrimidine under ultraviolet radiation. This could have been a missing link in the creation of the conditions on primitive earth for life to have formed.
ScienceDaily (Nov. 11, 2009) — NASA scientists studying the origin of life have reproduced uracil, a key component of our hereditary material, in the laboratory. They discovered that an ice sample containing pyrimidine exposed to ultraviolet radiation under space-like conditions produces this essential ingredient of life.
Pyrimidine is a ring-shaped molecule made up of carbon and nitrogen and is the basic structure for uracil, part of a genetic code found in ribonucleic acid (RNA). RNA is central to protein synthesis, but has many other roles.
"We have demonstrated for the first time that we can make uracil, a component of RNA, non-biologically in a laboratory under conditions found in space," said Michel Nuevo, research scientist at NASA's Ames Research Center, Moffett Field, Calif. "We are showing that these laboratory processes, which simulate occurrences in outer space, can make a fundamental building block used by living organisms on Earth."
They found that when pyrimidine is frozen in water ice, it is much less vulnerable to destruction by radiation. Instead of being destroyed, many of the molecules took on new forms, such as the RNA component uracil, which is found in the genetic make-up of all living organisms on Earth.
NASA Reproduces A Building Block Of Life In Laboratory