An international team of scientists at NASA have found sugar molecules on two different meteorites, the agency announced on Nov. 19.
The new discovery adds to the growing list of biologically important compounds that have been found in meteorites and supports the theory that chemical reactions in asteroids can play an important role in creating and supporting life, the space agency said in a statement.
Researchers said they discovered “ribose and other bio-essential sugars” in the extraterrestrial rock, adding that ribose is a “crucial component of RNA (ribonucleic acid)”—essential for the regulation and expression of genes.
“In much of modern life, RNA serves as a messenger molecule, copying genetic instructions from the DNA molecule (deoxyribonucleic acid) and delivering them to molecular factories within the cell called ribosomes that read the RNA to build specific proteins needed to carry out life processes,” they explained.
In a study published Monday in the Proceedings of the National Academy of Sciences, researchers analysed three separate meteorites, including one dating back billions of years that landed in Australia in 1969.
Previous attempts were made to investigate the meteors for sugar. However this time, the researchers decided to utilize a new technique using hydrochloric acid and water, and found sugars like arabinose and xylose in addition to the significant find of ribose.
“Other important building blocks of life have been found in meteorites previously, including amino acids (components of proteins) and nucleobases (components of DNA and RNA), but sugars have been a missing piece among the major building blocks of life,” the study’s lead author, Yoshihiro Furukawa, said in a statement.
The discovery of ribose also suggests that RNA evolved first and was later replaced by DNA because RNA molecules have capabilities that DNA lack, adding to the evidence that scientists are using to develop a clearer understanding of how life may have formed.
“RNA can make copies of itself without ‘help’ from other molecules, and it can also initiate or speed up chemical reactions as a catalyst. The new work gives some evidence to support the possibility that RNA coordinated the machinery of life before DNA,” the report said.
Furukawa added: “The research provides the first direct evidence of ribose in space and the delivery of the sugar to Earth. The extra-terrestrial sugar might have contributed to the formation of RNA on the prebiotic Earth which possibly led to the origin of life.”
The research team now plans to analyze more meteorites to see how abundant these sugars are and if have they a left-handed or right-handed bias, as some molecules come in two varieties which are mirror images of each other.
“On Earth, life uses left-handed amino acids and right-handed sugars. Since it’s possible that the opposite would work fine–right-handed amino acids and left-handed sugars. Scientists want to know where this preference came from,” the report explained.
In January, a report published by the American Association for the Advancement of Science said that researchers had found that two meteorites held other ingredients for life.
They included amino acids, hydrocarbons, other organic matter, and traces of liquid water which could date back to the earliest days of the solar system.