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DNA in inanimate objects?

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  1. Oct 6, 2015 #1
    I couldn't find much on this topic online.

    Besides their basic chemical structure, can inanimate objects be said to contain DNA molecules?
    They don't have to genetically replicate (or at least not quickly).

    Thanks for any thoughts! :)
     
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  3. Oct 6, 2015 #2

    Ryan_m_b

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    Unless it's put there by an organism (like a fly in amber) then no. I feel like there's more to your question that's not stated, could you elaborate?
     
  4. Oct 6, 2015 #3
    I am trying to wrap my head around this one myself. Let me try the opposite angle:
    DNA replicate themselves through genes that they form. Right? If DNA had no genetic structures that help their replication, would this be an inanimate object? And if yes, any examples? And if not, would that imply that DNA and genes always come in the same package?

    Thanks for your reply btw! I figured it would need to be some sort of a "living" structure.
     
    Last edited: Oct 6, 2015
  5. Oct 6, 2015 #4

    Ryan_m_b

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    No, I think we need to start with some terminology. DNA is deoxyribonucleic acid, it is a large double helix molecule composed of a sequence of nucleic acids. Genes are sections of that sequence that code for a functional RNA molecule or protein. DNA replication is a complicated processes involving many different enzymes, briefly this involves enzymes unravelling the double helix, reading the sequence and synthesising a new strand on the basis of that sequence. This video shows some brilliant computer constructed images of the process.

    Genetic structure means something specific, I'm not sure what you mean by it here. If you're asking if DNA is the only way to encode genes the answer is no, there are other molecules that can do the job, RNA viruses don't use DNA for example, but in nature DNA is vastly more ubiquitous because it has favourable chemical properties like being stable over much longer time scales.

    In theory there could be other molecules used for storing genomes but that would require a radically different cellular biochemistry. There are groups that investigate that as a way of hypothesising about life on other planets.

    No problem, I feel I'm still not understanding you completely though.
     
  6. Oct 6, 2015 #5
    Here is how I get it currently: DNA contain genes in their sequence. But other molecules can also have genes. It just happens that DNA are the ones that are doing well.
    My questions would then be:
    Are there any DNA molecules that don't contain genes? If molecules (DNA or not) don't contain genes, are they able to replicate? And if they are not able to replicate, what does that make them? Inanimate or animate (taking that being animate entails the ability to replicate)? And finally, what wold be any examples of these?

    I am guessing a piece of quartz rock is just bunch of atoms, no DNA or molecules there, so that doesn't count. And this is an example of a structure that doesn't have DNA and can't replicate, so it's inanimate. But is there an object that DOES have DNA, but can't replicate because doesn't have genes (or for some other reason can't replicate).

    I know I repeated a bit of myself but I hope I painted a better picture. Or am I totally of track here? :) Thanks again!
     
  7. Oct 6, 2015 #6

    Ryan_m_b

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    Not all of DNA codes for genes, a lot of the sequence contains regulatory regions that influence how genes are turned on or off. I can't think of any examples of DNA in nature that is used for something other than genome storage. As for being able to replicate DNA replication occurs because of enzymes involved in that process, without a genome those enzymes wouldn't be produced and beyond that the organism (or cell of an organism) wouldn't function.

    In terms of animate and inanimate I believe the definition of inanimate is "not alive." I don't believe any form of DNA is considered to be alive, it's an important component of an organism that is alive but that's not the same thing.

    Technically DNA viruses have DNA but can't replicate on their own. That's because a virus doesn't carry the necessary molecular equipment to synthesise new molecules, instead it infects other organisms with its own DNA and hijacks their components. The DNA in this case definitely codes for genes however. Along similar lines prions are self-replicating proteins, there's no DNA involved but the replicate by coming into contact with another protein the same as themselves and folding it into a different configuration. Like viruses they also depend on another organism to do the work, in this case synthesising the extra protein.
     
  8. Oct 6, 2015 #7
    That is very helpful!
    Just a few additional thoughts/questions:
    - So DNA viruses actually do have genes (as you said, all DNA store genes), but they need extra other molecular equipment to replicate themselves. Very cool.
    - As for the "life" part, my take was not that DNA is "life" but more that the process of DNA replicating (if it can) would be considered "life", because the process of reproduction is one of the main definitions of life. Or are there some other entities to consider before we can officially throw the term "life" into the pot?
     
  9. Oct 6, 2015 #8

    jim mcnamara

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  10. Oct 6, 2015 #9

    Ryan_m_b

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    No problem.

    Yes. Specifically viruses insert their DNA into a cell "tricking" the cell into producing more viruses. If you read up on the central dogma of biology that will give you a good grounding to understand how the information in genes is used to construct things.

    DNA cannot replicate on its own, if you had a solution of DNA doesn't matter how long you leave it you won't get more made. For DNA to replicate it needs to transcribe RNA, have that RNA translated into proteins and have those proteins replicate the DNA. All of that requires a metabolism to power it and supply the necessary "ingredients" and a barrier to prevent everything from floating away. Essentially it requires a cell.

    As for what life is there are a range of characteristics that an object has to exhibit before it is considered alive. Replication is only one of them:
    https://en.wikipedia.org/wiki/Life#Definitions
     
  11. Oct 6, 2015 #10
    Thanks again for all the answers! This really helped clarify so much.
    Just to recap, after all the details, the answer to the original question would be, yes, DNA can find itself in an inanimate environment. DNA itself is inanimate in the first place so it can either be involved in producing life (if it finds itself in a cellular environment, where its replication can be facilitated), or it doesn't have to produce life if such conditions are not met.
    Accurate enough?
     
  12. Oct 14, 2015 #11
    I was going to start a new thread, but then realized that this question is related to this one, just a bit of a flip side of itself. It might be a bit of an odd question, but here it goes:
    Are there any life forms that come into existence that don't involve DNA, genes and cells?
    Basically, is there life that just spontaneously (or caused by another stimulus) happens, and then just dies because it doesn't get replicated? Or goes in some other direction?
    Or is all life on earth strictly built/maintained using cells?
     
  13. Oct 18, 2015 #12

    Drakkith

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    Other than viruses, which straddle the border between life and non-life, all life is made up of cells which were originally created by the division of previous cells in a process known as biogenesis, the creation of new organisms from pre-existing life. Take this process back about 4 billion years and we arrive to an unknown period in the evolutionary history of life and a process called abiogenesis, the generation of life from non-living materials.

    It is believed that abiogenesis can no longer happen in the world today because living organisms would destroy any nascent pre-life (or, rather, simply keep them from forming in the first place)
     
  14. Oct 19, 2015 #13
    Thanks!! That really clarified things.
     
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