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Space Science

All of the Bases In DNA, RNA Have Now Been Found In Meteorites (sciencenews.org) 69

Posted by BeauHD from the origin-of-life dept.
Space rocks that fell to Earth within the last century contain the five bases that store information in DNA and RNA, scientists report April 26 in Nature Communications. Science News reports: These "nucleobases" -- adenine, guanine, cytosine, thymine and uracil -- combine with sugars and phosphates to make up the genetic code of all life on Earth. Whether these basic ingredients for life first came from space or instead formed in a warm soup of earthly chemistry is still not known. But the discovery adds to evidence that suggests life's precursors originally came from space, the researchers say. Scientists have detected bits of adenine, guanine and other organic compounds in meteorites since the 1960s. Researchers have also seen hints of uracil, but cytosine and thymine remained elusive, until now.
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All of the Bases In DNA, RNA Have Now Been Found In Meteorites More

All of the Bases In DNA, RNA Have Now Been Found In Meteorites

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  • Silly question (Score:5, Interesting)

    by asackett ( 161377 ) on Thursday April 28, 2022 @02:04AM (#62486098) Homepage

    Did not Earth itself "come from space" as an agglomeration of numerous smaller objects?

    • Re:Silly question (Score:5, Insightful)

      by Viol8 ( 599362 ) on Thursday April 28, 2022 @02:39AM (#62486132) Homepage

      Indeed. And the chances of life arising on a small meteorite vs a large rocky planet with huge amounts of water and compounds just right for complex chemistry in a liquid enviroment vs it arising in space on some tiny dry meteorite or dusty moon is so close to zero as not worth talking about, but the Life Arose In Space brigade will never get off their hobby horse.

      • That would be evident if base compounds also existed deep into the earth. Much deeper than the first evidence of single cell organisms. Right? On the other hand, if we find the same base bompounds in core samples on mars⦠then maybe these base compounds are less rare than previously believed.

      • Don't tell the "Space Brigade" that science also found the "same atoms" in space that exist on earth too. Please don't share the Hydrogen, Carbon, Oxygen, Nitrogen and Phosphorous atoms are found both all over the universe and in DNA. Seriously, heads will explode. It will only lead to more YouTube videos that no one wants to watch.

        It is almost as Earth is part of the Universe and made out of the same stuff as the Universe.... it is just crazy.

      • Re:Silly question (Score:5, Interesting)

        by Aristos Mazer ( 181252 ) on Thursday April 28, 2022 @08:21AM (#62486474)

        Almost no one (there are some real crazies out there) is suggesting that the nucleobases developed on meteorites. The question is whether they are extrasolar or locally formed. If they formed on an already-stable Earth, then the big question becomes "how did they get onto the meteors?" Given that they are in meteors, it seems to many to be more plausible that the meteors got them from something drifting in from outside the solar system rather than somehow lifting them off Earth and distributing them.

        • The various bodies in the solar system exchange material regularly.

          https://ui.adsabs.harvard.edu/... [harvard.edu]

          If organic molecules are found in meteorites, one possible explanation is that the material originally came from earth itself.

          • Right. The likelihood of a piece of Earth blasted into space having an initial orbit around the Sun that will eventually intersect with Earth is approximately 100%. That is inevitable due to physics.

            Of course, something could perturb that orbit like the Moon or Mars or Jupiter, but it tells you it is not weird luck that some former Earth material returning to Earth. Quite the opposite.

            • That's an interesting variation I hadn't heard. I agree that would skew the statistics in favor of Earth-origin for meteorite bases.

              • Remember that your typical orbit, absent significant perturbations, is an ellipse with the sun at a foci. Such an orbit will inevitably return to the same vicinity -- a location very very very near where Earth just was. It has to.

                Now, the Earth and Moon can offer significant perturbations, but if that is the source of the perturbations, then we know the hunk of rock returned to be very near Earth or Moon. There may now be a different ellipse as the orbit but the same logic holds.

                I probably stated my poin

        • Given that they are in meteors, it seems to many to be more plausible that the meteors got them from something drifting in from outside the solar system rather than somehow lifting them off Earth and distributing them.

          That is an astronomically large leap (pun intended). Venus, Earth, Mars was often pulverized with massive meteor strikes while they were covered in warm wet organic goos that did lift material out of orbit. Hypothesizing "outside of the solar system" answers nothing, because we are still looking for some kitchens of warm wet organic goos to provide the extra-solar universe with this material. Well, we have three such kitchens sitting right under our noses.

          I suppose we could imagine a protopanet near an a

          • If the small molecules turn out to be easy to make, yes, that is a better explanation. But thus far, no one has shown a way to form them from scratch. If they are very improbable (the hypothesis I hear most often given that no one can theorize alternative), we have to look for a place with long stability. Early bombard Earth is not particularly long duration.

            • Re: (Score:2)

              by Viol8 ( 599362 )

              " But thus far, no one has shown a way to form them from scratch"

              Newsflash - they did just that in 1952:

              https://en.wikipedia.org/wiki/... [wikipedia.org]

            • Sorry, but have you been missing the whole subject of stellar spectroscopy since the early 1960s? We see small organic molecules all over the universe down to the (steadily decreasing) concentration limits of our telescopes and spectroscopes. New molecules are eing detected (and announced) all the time.

              That I don't think these particular compounds have been reported before (and I haven't checked ; I've a feeling that at least the pyrimidine base compounds from which several of the nucleic acid bases are me

      • Indeed. And the chances of life arising on a small meteorite vs a large rocky planet with huge amounts of water and compounds just right for complex chemistry in a liquid enviroment vs it arising in space on some tiny dry meteorite or dusty moon is so close to zero as not worth talking about, but the Life Arose In Space brigade will never get off their hobby horse.

        To be fair, that's not a strong argument.

        In the scenario where many meteorites carry life's building-blocks - acting as seeds - arrive at various planets, it's only the large rocky planets with huge amounts of water and compounds just right for complex chemistry in a liquid environment where the seeds can take root and a species evolves to learn it happened.

        I'm not saying Terrestrial life originated somewhere else. I'm only saying the "what a coincidence" argument doesn't work.

        • Re: (Score:2)

          by Viol8 ( 599362 )

          Lifes "building blocks" were demonstrated to have been created in early earth conditions in the 1950s. Next...

          • The Miller-Urey experiment.

            To be fair, few geologists now consider the Earth to have had the sort of atmosphere that Urey put in his flask. But that doesn't matter really ; lots of atmospheres work for producing lots of different organic molecules. Working out which ones could have produced life-like metabolic and/ or genetic systems is the problem. And we'll probably never know for sure, for Earth ; we might find a system developing on the planet Zog in the future, but that doesn't mean that the exact sam

    • Re: (Score:1)

      by Anonymous Coward
      Yes, the elements we are made of were part of a star or many different stars and were disseminated by supernovas, The article here pushes forward the idea that the life on Earth was seeded (panspermia), rather than creating itself from accident from the primordial soup of chemicals.

      • Re:Silly question (Score:4, Insightful)

        by Muros ( 1167213 ) on Thursday April 28, 2022 @07:26AM (#62486382)
        The article does not support panspermia. Panspermia is the hypothesis that life came from other star systems, essentially a "turtles all the way down" explanation for the origin of life. This article supports a hypothesis that has been around for a good while, that life arose on earth from the combination of chemicals that may form more easily on comets and asteroids than on planets.
        • I wouldn't say panspermia amounts to "turtles all the way down." It's like a forest fire, almost all the trees caught fire from the other trees, vs. being the one that originally got hit by lightning. But it's acknowledged that some tree was first.

          (I'm not saying the relative likelihoods hold for the origin of life, much less speaking for all panspermians, since I never encountered the word before your post)

          • I wouldn't say panspermia amounts to "turtles all the way down."

            I would. It's taking a difficult problem (OOL, on Earth), then throwing away pretty much all the evidence we have (whatever evidence we find on Earth) and declaring the problem to be insoluble, so it mush have happened somewhere far away where we won't ever have any evidence about how it happened.

            "Turtles all the way down" is an extremely polite way of describing panspermia. "Worse than useless" and "not even wrong" are other excessively polit

      • Re: (Score:2)

        by mark-t ( 151149 )
        Doesn't that just push the question of the ultimate origin of life back one level, then?
        • Sure, like anything. Ultimately there is no "explanation." Eventually you get back to an initial event that happened for no reason (call it the big bang), or else eternity (turtles all the way down). Neither makes any sense.
          • Well, time (spacetime, remember) itself arose (or inflated from infinitely small, whatever that means for time), at or around the big bang event, so in that model, it probably doesn't make sense to talk about eternity. Another subtle point: "For no reason that we can discern or yet theorize" is very different than "for no reason".

            All your concepts are belong to us.

            • "For no reason that we can discern or yet theorize" is very different than "for no reason".

              Sure, but if it wasn't for no reason, then it was for a reason, so that is the more fundamental cause / explanation.

              That's why I say the chain of cause and effect either starts somewhere, or doesn't start anywhere. And neither makes sense.

    • Don't spoil it! I want to tell people my DNA is extraterrestrial.

  • Or are adenine, guanine, cytosine, thymine and uracil running wild on some space rock?

    • If nothing else it indicates that humans are free to totally destroy life on this planet since it must exist elsewhere.
      • Don't let Vlad (Darth) Invader see that post.
        • Humanity has, in its geologically short appearance on its planet has developed for itself immense powers unmatched by any other living creature which, used wisely, could do remarkably wonderful things for all living creatures of the planet and used foolishly could destroy much of planetary life. It has been said that absolute powers corrupt the possessor absolutely. but power, in itself, can be used well and it is not the power that corrupts the user but rather that the user can corrupt the power. In our cu
          • Don't worry. We're not going to extinguish the prokaryotes. Life will survive. Humans, not necessarily.

            Well, life will survive until the Sun goes red giant. Maybe for a while after that, maybe not until then (the oceans will boil long before that).

            • The use of the word bird or dinosaur is not a scientific but a linguistic differentiation. When I tell somebody there is a dinosaur in my back yard it is well understood it does not refer to a sparrow or a chicken. It is not rational to absolutely predict anything, It seems likely that many forms of life will find it very difficult to survive in the near future and much of life is interdependent. It lies well within possibility that some activity may sterilize the whole planet as some other planets fully de

              • When I tell somebody there is a dinosaur in my back yard it is well understood it does not refer to a sparrow or a chicken.

                Odd.

                When I tell someone there is a dinosaur in my backyard people do precisely expect that I'm talking about a Seagull, Sparrow or (currently chowing on the window-mounted dinosaur-feeder) a Great Tit. Because I've been having this conversation for decades.

                Language change can be random, or directed.

                It seems likely that many forms of life will find it very difficult to survive in the n

                • Evidently we are hanging out with different sets of people. Nobody I know would associate seagulls or sparrows with the remark that I would make that I just saw a dinosaur. And also the thought that there is no life elsewhere in the universe has no emotional content at all for me except doubt. I don't give a damn whether or not there is life beyond Earth. If Mars has no life that means it's sterile and so far, no life has been discovered there. If the radioactive level on this planet reaches a certain leve

                  • If the radioactive level on this planet reaches a certain level it will kill all life exposed to it.

                    That would be a very high level, and I don't think that enough heavy nuclei exist in the accessible (top 10km) part of the Earth to do that. I'm not sure what DNA replication error rate for Deinococcus radiodurans [wikipedia.org] is (it's in the Wiki article), but it's probably not the highest error rate that DNA can endure - it's just the highest error rate that has been selected for.

                    Obviously we have selected different

                    • I am not denying your substantial right to firmly link birds to dinosaurs, merely connecting common words for meaningful communication, If Jurassic Park was a film about life in a chicken coop, I sincerely doubt it would do well in the box office. One of the outstanding qualities of radioactivity is that its long persistence can distort the functional directives of DNA to destroy its functional utility. Over a period a long exposure to it might make the DNA more effective but that possibility is so random a

    • If you define God as Spinoza did, then yes. :-)

    • I, for one, welcome our new meteorite overlords!

    • Perhaps... Perhaps not... Either way it is no excuse to stop doing additional research. Is it a case those chemicals are so common that they just kinda form everywhere, so we made these chemicals when the earth was formed. while those chemicals were forms with the asteroids independently. Or are these chemicals brought to earth solely from the outside the earth. If that is the case, what particular issues created the chemicals on the asteroids that couldn't happen on earth.

      The Bible is not a science bo

  • All your base are belong to us (Score:3, Funny)

    by bob122989 ( 912229 ) on Thursday April 28, 2022 @04:56AM (#62486202)
    All your base are belong to us.

  • Contamination (Score:5, Insightful)

    by backslashdot ( 95548 ) on Thursday April 28, 2022 @05:07AM (#62486208)

    Seems contamination cannot be 100%, or even 99%, ruled out. The best way to be sure is for a robotic probe to perform this experiment in-situ on an asteroid.

  • Life itself did not necessarily come from space. (Score:5, Informative)

    by jdagius ( 589920 ) on Thursday April 28, 2022 @05:35AM (#62486238)
    The article merely claims that important components (nucleotide bases) were found in meteorites, but that does not prove that life came from space, or even that these bases could not have been made on Earth.

    In fact, in 1952, Stanley Miller and Harold Urey conducted an experiment that demonstrated how amino acids could have been generated on primitive earth from lightning bolts. https://en.wikipedia.org/wiki/... [wikipedia.org]

    But DNA does not appear "naked" in nature. And no theory yet has satisfactorily explained how DNA itself evolved from these components, no DNA has been found in meteorites.

    So life remains a big mystery.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      But DNA does not appear "naked" in nature. And no theory yet has satisfactorily explained how DNA itself evolved from these components, no DNA has been found in meteorites. So life remains a big mystery.

      Not quite: https://en.wikipedia.org/wiki/... [wikipedia.org] The theory generally goes: RNA life came first and then evolved into DNA life as DNA was more stable. There are some theories that there was a step before RNA.

      • Re: (Score:2)

        by jdagius ( 589920 )
        "... RNA life came first and then evolved into DNA life ..."

        Which came first, chicken or egg? The answer, of course, is DNA!

        But modern molecules of RNA need DNA to reproduce themselves, so not clear how RNA existed before DNA. There is on-going research to determine how an ancient form of RNA could nave replicated, without DNA. Maybe some kind of "self-assembly"? These pre-DNA RNA-life forms would just be plain molecules, without any protein structure to protect them. Hard to image how they could su

        • RNA can also reproduce itself. That is what viruses do.

          RNA is almost the same as DNA, but DNA is more stable. RNA is what actually makes proteins, so almost certainly came before DNA.

          But what came before that?

        • Which came first, chicken or egg? The answer, of course, is DNA!

          The answer is "egg". Eggs, even amniotic eggs, existed long before chickens.

    • before DNA and proteins.

      https://www.khanacademy.org/science/ap-biology/natural-selection/origins-of-life-on-earth/a/rna-world

  • I bet many forms of metal oxides used in digital tapes or disks have also been found in meteorites. Does not mean nature was close to putting out, say, a Linux system.

    • But nature did put out a Linux system...

      via us evolved humans as intermediaries.

      Don't you sometimes get the feeling that your main purpose in life is to keep your smartphone safe and regularly supplied with energy?

      • We have the ultimate answer, but we're still working on the ultimate question.

      • Re: (Score:2)

        by gweihir ( 88907 )

        But nature did put out a Linux system...

        via us evolved humans as intermediaries.

        Hahahaha, no. That is conjecture.

        • Haha, yes. Evolution is well established, and just the slightest bit of applied thinking makes it obvious that evolution can apply to polymer molecules to kickstart the whole process, as long as there are plenty of flexibly reactive ingredients around trapped together (e.g. in a gravity well) and as long as there is a steady energy flow (a non-equilibrium thermodynamic situation in an energy regime that permits common elements and molecules to form solid, liquid, and gaseous forms in the same area, and to r

  • I misread the title as a play on the meme.

  • More information ... (Score:3)

    by kbahey ( 102895 ) on Thursday April 28, 2022 @03:38PM (#62487668) Homepage

    This article in Sky and Telescope [skyandtelescope.org] has more details.

    They ruled out contamination as a source for the nucleobases, by sampling the soil where the Murchison meteorite was found in, and the concentration of nucleobases is clearly different.

    They also found that the pyrimidine bases are of a very low concentrations that the origin for them has to be geochemical synthesis on Earth, not meteoritic ...

    But actual examination of space rocks like Ryugu and Bennu will hone in the findings more ...

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