Re: Clarification on the natural causes of mutation.


Noone Inparticular wrote:
> Frank Sullivan wrote:
> > Noone Inparticular wrote:
> > > Frank Sullivan wrote:
> > > > I understand that radioactivity can cause mutations, but what are the
> > > > other natural sources?
> > >
> > > There are a number of chemical agents that can induce DNA damage,
> > > mostly alkylating agents. However, keep in mind that most of the
> > > mutation arises from chemical agents are really mutations which arise
> > > from errors made when repairing the damaged DNA.
> > >
> > > Furthermore, excisions, insertions and transpositions (a kind of
> > > insertion) are all forms of mutations. They are not caused by a
> > > chemical agent and instead are caused by errors made when repairing or
> > > replicating DNA or by biological agents (such as retroviruses).
> > >
> > > > Do nucleotides just spontaneously change do to
> > > > the random nature of quantum particles, or is there some chemical
> > > > reaction that occurs? Do some nucleotides just end up pairing up
> > > > incorrectly somehow?
> >
> > Thanks very much for the information. I regrettably have no idea how
> > the DNA repair process works and so is definitely a naive question, but
> > if the repair process is what causes the mutation, then what invokes
> > the repair in the first place?
>
> Well, sometime the errors happen when DNA is replicated (that is they
> can happen even if there is no damage to the DNA). There are multiple
> ways in which a cell can detect damage to its DNA, but all are rather
> complex. I'm not trying to put you off, but a complete discussion of
> this would require a rather large book. Basically there are proteins in
> the cell which can detect DNA damage. These proteins then signal to
> other proteins, thus activating a number of pathways, including DNA
> repair, replication and cell cycle control and sometimes, depending on
> the circumstances, death inducing (called apoptosis) pathways.
>
> If you are interested, I can forward to you a few reviews on this.

That would be awesome, but only if it's not too much trouble.

.

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