The U.S. National Aeronautics and Space Administration's (NASA) scientists, who were studying the origin of life, say they have reproduced the three building blocks of life: uracil, thymine and cytosine in the lab.
The scientists explain that pyrimidine contained in an ice sample produced these three key ingredients when exposed to ultraviolet radiation in conditions similar to what is found in space: with high radiation and very low temperatures and in a vacuum.
NASA also describes pyrimidine as a ring-shaped molecule, which is made of nitrogen and carbon. It is the central structure for thymine, uracil and cytosine, which are part of a genetic code found in ribonucleic (RNA) and deoxyribonucleic acids (DNA). DNA and RNA are key to protein synthesis. However, they also have various other roles.
In this instance, thymine, uracil and cytosine have been reproduced non-biologically in a lab environment and in conditions similar to that of outer space.
Michel Nuevo, a research scientist at the agency's Ames Research Center, Moffett Field, California, suggests that lab processes have the capability of producing building blocks of life found on Earth.
The pyrimidine molecule is also found in meteorites, but scientists are unaware of their origin.
"Molecules like pyrimidine have nitrogen atoms in their ring structures, which makes them somewhat wimpy. As a less stable molecule, it is more susceptible to destruction by radiation, compared to its counterparts that don't have nitrogen," says Scott Sandford, who is a space science researcher at Ames.
The research team wanted to examine if pyrimidine could persist in space. They also wanted to see if pyrimidine could undergo reactions, which could change it into more complex organic species, like thymine, uracil and cytosine.
When pyrimidine is frozen in ice, the researchers found, it becomes less vulnerable to destruction by factors such as radiation. However, pyrimidine is more susceptible to damage in open space.
The origin of life on Earth remains a mystery. However, the building blocks of life are believed to have existed on Earth since its formation. The life-forming process on the planet is also possible when any other new planet forms in space.
