Scientists found the last two DNA nucleobases in meteorites, suggesting space may have contributed to life’s building blocks on Earth.
Using new analyses, scientists have just found the last two of the five informational units of DNA and RNA that had yet to be discovered in samples from meteorites. While DNA formation in a meteorite is unlikely, this discovery demonstrates that these genetic pieces are available for delivery and could have contributed to the development of the instructional molecules on early Earth. The discovery, made by an international team with NASA researchers, adds to evidence that chemical reactions in asteroids can produce some of the building blocks of life, which could have been delivered to ancient Earth by meteorite impacts or perhaps the infall of dust.
All DNA and RNA, which contains the instructions to build and operate every living being on Earth, contains five informational components, called nucleobases. Until now, scientists scouring extraterrestrial samples had only found three of the five. However, a recent analysis by a team of scientists led by Associate Professor Yasuhiro Oba of Hokkaido University, Hokkaido, Japan, identified the final two nucleobases that had eluded scientists before.
The Mystery of Limited Nucleobase Diversity in Meteorites
Nucleobases belong to classes of organic molecules called purines and pyrimidines, which have a wide variety. However, it remains a mystery why more types haven’t been discovered in meteorites so far.
“I wonder why purines and pyrimidines are exceptional in that they do not show structural diversity in carbonaceous meteorites unlike other classes of organic compounds such as amino acids and hydrocarbons,” said Oba, lead author of a paper about the research that was published today (April 26, 2022) in the journal Nature Communications. “Since purines and pyrimidines can be synthesized in extraterrestrial environments, as has been demonstrated by our own study, one would expect to find a wide diversity of these organic molecules in meteorites.”
“We now have evidence that the complete set of nucleobases used in life today could have been available on Earth when life emerged,” said Danny Glavin, a co-author of the paper at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
New Techniques Yield Delicate Nucleobases
This newly discovered pair of nucleobases, cytosine, and thymine, have been elusive in previous analyses likely because of their more delicate structure, which may have degraded when scientists previously extracted samples. In the earlier experiments, scientists created something of a “meteorite tea,” placing grains of meteorite in a hot bath to let the molecules on the sample extract into the solution and then analyzed the molecular makeup of the extraterrestrial broth.
“We study these water extracts since they contain the good stuff, ancient organic molecules that could have been key building blocks for the origin of life on Earth,” said Glavin.
Because of how delicate these two nucleobases are, the team was initially skeptical to see them in the samples. But two factors may have contributed to the new discovery: first, the team used cool water to extract the compounds instead of hot formic acid — which is very reactive and could have destroyed these fragile molecules in previous samples. Second, more sensitive analytics were employed that could pick up on smaller amounts of these molecules.
“This group has managed a technique that is more like cold brew than hot tea and is able to pull out more delicate compounds,” said Jason Dworkin, a co-author of the paper at NASA Goddard. “I was amazed that they had seen cytosine, which is very fragile.”
Implications for the Origins of Life on Earth
The finding doesn’t provide a smoking gun as to whether life on Earth got an assist from space or came about exclusively in the prebiotic soup in the planet’s infancy. But completing the set of nucleobases that make up life today, in addition to other molecules found in the sample, gives scientists who are trying to understand the beginning of life more compounds to experiment with in the lab.
“This is adding more and more pieces; meteorites have been found to have sugars and bases now,” Dworkin said. “It’s exciting to see progress in the making of the fundamental molecules of biology from space.”
Not only did this analysis add to the kit for those modeling the inception of life on Earth, it also provides a proof of concept for a more effective technique to extract information from asteroids in the future, especially from the samples of Bennu making their way to Earth in the next year via NASA’s OSIRIS-REx mission.
Reference: “Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites” by Yasuhiro Oba, Yoshinori Takano, Yoshihiro Furukawa, Toshiki Koga, Daniel P. Glavin, Jason P. Dworkin and Hiroshi Naraoka, 26 April 2022, Nature Communications.
DOI: 10.1038/s41467-022-29612-x
The research was supported by JSPS KAKENHI Grant Numbers JP21H04501, JP21H05414, JP20H02019, 21KK0062, 21J00504, JP20H00202 and JP20H05846; NASA Astrobiology Institute through award 13-13NAI7-0032 to the Goddard Center for Astrobiology, NASA’s Planetary Science Division Internal Scientist Funding Program through the Fundamental Laboratory Research (FLaRe) work package at NASA Goddard, and a grant from the Simons Foundation (SCOL award 302497). This study was conducted in accordance with the Joint Research Promotion Project at the Institute of Low Temperature Science, Hokkaido University (21G008).
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
10 Comments
What about creation? That God simply created everything. Nothing cannot come from nothing. In order for anything to have been there had to have been a creator. The biggest problem people have with Gods word is”In the beginning God…” What is so difficult to accept about creation and God? Look at the eye, look at the ear, chance? I dont think so. Go have a look at “Answers in Genesis”. God created everything. Stop denying God.
It seems most humans are too vain and insecure to accept the rather obvious fact that their finite existance is as random as it is insignificant; and, like all other organic life forms, eventually and finally each of us will inevitably cease to exist. Stop denying reality.
Who created god? And what created that which created god? Or do you not like being held to the same standard that you hold others? So you think that your bronze age goat herder mythology books explains perfectly well what happened in the beginning, yet scientists through billions of hours of research have been able to explain all these different things, giving us the technology to reach to the moon, cure diseases, extend life, etc etc. Meanwhile your religions, when they were in absolute control gave us nothing but snake oil salesmen, lies, wars and no technological advancement. So the age of religion was called the dark ages, yet the age of science is called the enlightenment. So stop babbling about things you do not understand in the hopes of justifying your myth which alleviates your fear of the unknown. Your delusions are fine if you keep them to yourself, but stop trying to poison others with your amygdala based nonsense.
PS if you really think science os wrong on evolution then maybe you should stop using all the fruits of science, the automobile, healthcare, computers etc, just pray to your supposedly powerful god to have all those things done for you by angels. Or continue to use sciences benefits, thereby showing how much of a hypocrite you actually are.
PPS the evolution of the eye is easily demonstrable from the most rudimentary of eyespots to the most advanced mammalian eyes.
If god can’t delegate, then why do you feel the need to troll on god’s behalf?
Have you considered that God by nature had no creator and that the universe was created outside of space and time? For over 70 years man has been trying to recreate how life was created from non life and has made little progress to the point that even leading atheists agree that ship has sailed.
Isn’t God in everything and everywhere? We don’t have to interpret what the bible says literally, this is the problem. We are the ones who make babies even though it is all God’s work. In the same manner, the Asteroid Belt makes the nucleobases of our DNA.
Its a lucky thing that when asteroids hit earth that they remain cool, allowing the “cold brew” to do its thing. I had always thought that an impact like that might generate some heat, but I guess not.
Never mind god. the littering fine from the local council will be the wrath..fly tipping..have mercy. :0 . BAZZIINNGGAAA.
Some things are true even if you don’t believe it. We you/I are significant and unique. Why is CERN always looking for “GOD” particle?
“God” is a simple answer where man runs out of facts and understanding. The boundaries of understanding will continue to grow as the domain of god shrinks.