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The 'random' in random mutation

  1. Feb 6, 2007 #1
    What does the 'random' in random mutation really mean?
  2. jcsd
  3. Feb 6, 2007 #2


  4. Feb 6, 2007 #3


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    Staff: Mentor

    Could you be more specific as to what your question is?
  5. Feb 6, 2007 #4
    I wanted to know where the border between random and nonrandom is. If there is a clear seperation, if it is possible to detect nonrandom mutations, or if some of the known ones have already crossed the border.
  6. Feb 7, 2007 #5
    The main difference between a random and a nonrandom event is that a nonrandom event is influenced directly by something that causes that mutation. A random error in DNA replication as a cause of error(s) made by the system by chance can be considered a random mutation. Mutation that occur by exposure to UV radiation can be defined as a nonrandom mutation.
  7. Feb 9, 2007 #6
    I see u talk about 'replication errors', but these are caused by something aswell im sure u agree. So what u are really saying is that when a mutation has an outside cause, it is not random?
  8. Feb 9, 2007 #7
    These replication errors is not so much caused by something, but rather the lack of something in some cases or that one or more steps in the progress was not functioning correctly. A human is not a machine. This is entirely different from mutations that occur due to a direct, external source, such as chemicals or UV radiation.

    I'm saying that the mutations that arise from coming into contact with mutagenic radiation such as UV is different from mutations that occur as a result of the phenomena described in the paragraph above.
  9. Feb 10, 2007 #8
    Hey I just learned about this in cell and molecular biology, from what I understand mutations that occur are random and constant across the DNA of different species, the mutation rate being 1 nucleotide mutation for every 1 billion nucleotides. What "random" in random mutation rate means is that the mutation can happen anywhere along the genome of an organism, not just in specific area along the genome. There are some genes that seems to mutate more than others when you compare the genomes of different species, while other genes seem almost identical. You might then wonder, how are mutations random, if some genes seem to mutate more then others through time. Well the answer to that is, if there is a mutation on a gene that is critical to the life of the cell, the cell well not live to pass on that new gene to its offspring, while non lethal mutations(mutations on genes that are not essential to life)
    do allow a cell to live and pass on the mutations to its offspring. An example of some genes being well conserved through out eukaryotes is the gene that encodes for histone protiens, which is a dna packaging protien, you could put a histone protien of cockroach in a human cell and it would be functional.
    Ok im done rambling,:rofl: hope this helps.
  10. Feb 10, 2007 #9
    Be careful with labeling mutations as only harmful, for that is not true. Mutations can be either harmful, beneficial or neutral.
  11. Feb 11, 2007 #10
  12. Feb 18, 2007 #11
    all too simple

    I have mused on this quite a bit and wanted to respond to the original question. There are a few different forms of mutation. We can have a single base pair substitution. We might also have the transposition of a very large sequence. A foreign sequence can invade via virus or other forms of horizontal gene transfer. Some mutations are induced by UV or other genetically destabilizing factors, in a cancer cell mutations rates are much faster than normal cells. We can see quite clearly that mutation is not entirely random, rather it is a set of a few distinct classes of mutation.

    The question becomes, are these classes random. Its really quite impossible to prove randomness. In order to prove this, you must find every possible source of information, use every available algorithm upon it and prove that none of it can be used to predict the events that are occurring. Rather, randomness is a simplifying assumption that has been made in a few places in science.

    I am personally very interested in the prospect of using currently available information sets to find rules of mutation in the genome. We are in the middle of an influx of the highest resolution nucleic acid data in history (this still only represents a small portion of the nucleic acid diversity in life, not just in the genome, but in its many other environmental forms). Already work is being done to compare the sequences of various sequenced genomes in order to determine patterns of mutation and how this might be correlated to the biology they relate to.
    Last edited by a moderator: Feb 18, 2007
  13. Mar 16, 2007 #12


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    I'm not sure how to provide a technical definition of random in this case (perhaps unpredictable or, as noted above, directionless?), but I'd note that 'random' does not mean 100% random since some mutations are more likely than others.
  14. Mar 22, 2007 #13
    I think "random" can be more accurately defined as being unpredictable
  15. Mar 24, 2007 #14
    Random means occuring according to a probablity distribution, not 'arbitrary' or indeterminable. It also means without purpose within the present context.
  16. Mar 26, 2007 #15
    randon its most uncertain thing
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