A re-examination of meteorites has found all 5 building blocks of DNA and RNA, which suggests that early in Earth’s history these space rocks may have delivered the chemical ingredients vital to the origin of life.
Scientific first: Meteorites contain the instructions for life and control of genes
The notion that the seeds of life could have been delivered to Earth from elsewhere in the universe just got a huge boost, as a re-examination of meteorites that struck Earth billions of years ago contain both DNA and RNA.
All the amino acids necessary to form DNA and RNA, the organized, self-replicating assemblies of molecules we define as life on Earth and the necessary prebiotic material to help the development of life, have been found in meteorites for the first time, the Independent/Yahoo! News reported.
New techniques yield startling find
Scientists examined meteorites that landed in the United States, Canada, and Australia.
Previously, scientists had detected three of the five chemical components needed to form DNA, as well as detecting RNA. But these previous techniques used harsh methods that may have destroyed evidence.
Using new techniques that were more sensitive and not using strong acids or hot liquids, scientists now discovered that the meteorites contained all five components of DNA and RNA, known as nucleobases, CBC Canada reported.
DNA is the molecule that carries genetic instructions in living organisms, while RNA is the molecule crucial for controlling the actions of genes.
Building blocks of life found
“We found a diverse range of organic materials, including nucleobases — our basic building blocks of life,” said lead author of the study Prof. Yasuhiro Oba, an astrochemist at Hokkaido University, Japan, the Sun reported.
The research was carried out by researchers at Hokkaido University’s Institute of Low Temperature Science in Japan, and the study was published in the journal Nature Communications.
“These could have been delivered to the Earth on asteroids, meteorites, comets, and interplanetary dust particles four billion years ago when our planet was being bombarded by debris from outer space,” Prof. Oba continued. “We believe the influx of these organics played an important role in the evolution of life on Earth.”
“This is a very exciting discovery which expands our understanding of how life started,” Oba added.
Was life on earth seeded from elsewhere?
The most profound implication of this new discovery of DNA and RNA in meteorites is that the building blocks of life did not originate on earth but were “delivered” here from elsewhere in the universe as a type of seeding process.
The study authors wrote that material delivered by asteroids may have “contributed to the emergence of genetic properties for the earliest life on earth.”
This hypothesis goes back at least 50 years and contends that genetic material may form on carbon-rich asteroids then be carried to earth as meteorites that are small enough to “soft land” without vaporizing the prebiotic material they contain.
In 1969, one such meteorite landed in Murchison, Australia. Scientists found it contained many amino acids, which suggested interstellar chemistry could create the ingredients necessary for life.
Well-known planetary scientist Carl Sagan backed this theory. In the 1990s, Sagan suggested that a higher rate of meteorite impacts that were seen in Earth’s formative years could have delivered a more significant amount of material to the planet’s surface.
Based on the findings in this latest study, Professor Oba agrees: “The absolute abundance of nucleobases of extraterrestrial origin could be enough for further chemical reactions on the early Earth.”
