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As far as I know, DNA is the construction protocol of all organisms on Earth.

Does it change when influenced by time and environment (physical laws)?

As parents with schizophrenia are more likely to have children with schizophrenia and an individual with no genetic predisposition for schizophrenia can suffer from such a condition because of drug abuse or environmental influence, does this prove that human DNA is changing during our lifespan?

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migrated from skeptics.stackexchange.com Oct 4 '13 at 2:31

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This question is more appropriate for a biology Stack Exchange. But the answer is that "yes, each cell's DNA changes over time." I think what you might mean though, is "does all my DNA change in precisely the same way?" and the answer to that is "no." –  Larry OBrien Oct 3 '13 at 23:13
    
Changes in your DNA occur pretty much every minute of your life. You have trillions of cells, each of which contains about a meter of DNA. Tiny changes happen all the time. –  terdon Oct 4 '13 at 14:55
    
I think this perspective in Science about genome mosaicism is appropriate here PMID:23888031. Basically, not only our genomes change, but it changes differently for each cell. –  ddiez 2 days ago
    
This related post will probably interest you –  Remi.b 8 hours ago

3 Answers 3

To quickly answer your question, yes DNA changes over the life time of many organisms including humans. You have a whole host of mechanisms in your body that try to prevent your DNA from changing, but they are not perfect.

A good example of this is DNA degradation due to aging. When discussing aging in biology, we use the technical term senescence. Of interest here is the shortening of telomeres due to mistakes made in your cells as they continue to divide (copying the DNA to each new daughter cell).

In a grown adult, there's not some master well of DNA somewhere such that if you change it there it will immediately change the DNA throughout your body. Most of the cells in your body have DNA in them (red blood cells are just one example of cells that don't have DNA in the traditional sense). Most of these cells can and will divide over time (mitosis) to produce new cells with copies of that DNA. However, there are also plenty of cells that don't divide often or at all in healthy adults. If one is concerned about schizophrenia, it would be important to note that many neurons in the CNS are in this group of static cells.

Considering environmental effects, there are plenty of things that can change your DNA. Radiation, gamma and x-rays in particular, do a great job of disrupting, degrading, and occasionally mutating DNA. The class of chemicals and physical agents that can change DNA are called mutagens. This shares a root with the verb mutate, which is when something is acting on genetic material to cause it change.

You will note that I said genetic material, and not DNA. Without getting too far into the debate of what is "alive," DNA is most certainly not the only "construction protocol" for earthly organisms. RNA is one common alternative, but there are weirder ones that are hard to describe like prions.

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I have read that in parents DNA there is a code that guarantee their children to will more likely be proned to be better musicians or have better logic or just be better in something specific than other children. If this is true does it mean that during my life part of my way of thinking , my gifts will affect my DNA over time? So for example if my 10xgrand mother was musician and my 9xgrand mother was musician and so on untill i was born Does it mean that im proned to be musician and its coded in my DNA because of DNA changes in our geneological tree –  Flux Oct 4 '13 at 11:49
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@Flux your last comment makes no sense. Yes, you inherit characteristics (including, possibly, musical ability) from your ancestors. That does not mean that events during your life time will affect your DNA. Your DNA will change during your life because of damage and mutations but not because you become a better musician. –  terdon Oct 4 '13 at 14:53
    
@terdon: see my comments to vonMises's answer. Epigenetic changes to the genome happen because of environmental changes, mutation is not the only way to change genetic information. –  nico Oct 4 '13 at 16:08
    
@nico of course, but do you really think that learning to play an instrument will result in inheritable epigenetic changes? And whether or not epigenetic changes are actually changes in DNA is debatable. Anyway, my main point was that I simply could not understand the OP's comment: "I have read that in parents DNA there is a code that guarantee their children to will more likely be proned to be better musicians or have better logic or just be better in something specific than other children." Can you? –  terdon Oct 4 '13 at 16:12
    
@nico Darn. After reading his comment, I was thinking about coming back to include info on epigenetics, but you beat me to the punch. There are of course some really good questions not being asked here which are the subject of current research. –  Atl LED Oct 4 '13 at 16:17

A DNA change will only be passed on if it occurs in a germ line cell (the cells that become eggs or sperm). If you have a mutation in, say, a liver cell, that will not be passed on.

But I dont think thats what you are talking about. From reading your question and comment closely I think the answer is "no". A person who becomes schizophrenic because of drug use does not become any more prone to having schizophrenic kids than a person who doesnt do drugs. Drugs can upset the chemical balance in your brain and that can mimic certain genetic diseases, but what happens in your brain because of drug use can absolutely under no conditions be passed on to your child.

In your piano comment things are slightly more complicated. Being good at playing piano is a result of a complex interaction of many factors, some of which may be genetic. A long line of pianists generation after generation may be a result of genes that, say, sharpen a persons auditory perception so they can hear and interpret notes better. However, I am sure that the parents encouraged piano playing and practice for their children, which is just as important.

But most importantly, playing the piano a lot will not in any way cause changes to your DNA that will make your children better at playing the piano. Your genes dont care how well you play the piano. Mutation is random, and that is the only way DNA can change.

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A person who becomes schizophrenic because of drug use does not become any more prone to having schizophrenic kids than a person who doesnt do drugs. This is not that obvious. First, if drugs are taken during pregnancy/nursing they may as well influence the child. Second it is now well known that many drug can produce epigenetic modifications that, in certain situations, can be transmitted transgenerationally. –  nico Oct 4 '13 at 16:02
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Mutation is random, and that is the only way DNA can change.. This is not true. Mutation is not necessarily random, mutagens may be more or less selective. Also, again, mutation is not the only way DNA can change, there are plenty of epigenetic changes that can play a big role in shaping behaviours. Just as an example, you may want to have a look at this paper: ncbi.nlm.nih.gov/pubmed/22941276 –  nico Oct 4 '13 at 16:04
    
in response to your first comment, you completely ignored the second half of the sentence. I dont care that drugs can affect a fetus, they are not specifically going to change the fetuses DNA so that it has a schizophrenic gene –  von Mises Oct 4 '13 at 18:02
    
I understand the need to nit pick, and you are correct, but unless there is an epigentics paper that comes even close to doing what the OP is asking, I think saying "yea but sometimes..." will only mislead him. –  von Mises Oct 4 '13 at 18:10
    
sorry, but how can you say that it is impossible for a drug to affect a foetus so that it becomes schizophrenic? I can see many biologically plausible mechanism for that. Your answer is misleading because you are saying that the effect of the drug "can absolutely under no conditions be passed on to your child". Which is not necessarily true. –  nico Oct 4 '13 at 18:15

It's become quite clear that your active genome changes all the time, due to various effects. There is also gathering evidence that epigenetic changes can occur in somatic cells and be inherited by the offspring. But these seem to be stress-related.

So, for schizophrenia: If the family had a gene that triggered schizophrenia, which was normally inactive, then stress/drugs could cause an epigenetic change which would make the "schizophrenia gene" active. And this epigenetic change could conceivably (see what I did there?) be passed along to offspring.

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+1, however it is to note that stress (depending on the definition of stress that you want to use, some are rather large) is not the only stimulus that can generate epigenetic changes. For instance maternal behaviour is well known for having epigenetic effects (e.g. ncbi.nlm.nih.gov/pubmed/15220929). Surely, you may say that at the end it is stress-related, as you modulate GR, but it is not directly caused by stress (again, you should define stress more clearly so we know we're talking about the same thing). –  nico Oct 6 '13 at 8:58

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