Thread: Questions about dna.

When mutation happen in one cell, is it determined that all other cells in the body will get the mutation eventually?

If mutation only happen in some specific cells,
Is it because of nonliving causes, like radiation?

If mutation happens in all cells in the body,
Is it because of a virus or a bacteria, that spread the mutation?

Are some mutations reversable? If there is, name some?

How do dna in one cell communicate with dna in another cell to tell it to mutate?
Something tells me that dna has a boss. And that dna itself dont communicate with another dna in another cell.

Will junk dna get information only if all the other places in the dna is used up with letters?

Maybe junk dna is holding the secret of mutation, or junk dna is the catalyst to the rest of the dna's evolution.

Originally Posted by Thermaltake

When mutation happen in one cell, is it determined that all other cells in the body will get the mutation eventually?

No.

As in No.

Unless it is in a germ cell before fertilisation, or the fertilised egg before the first division.

The formulation of the question indicates that the situation presumes the presence of other cells besides the afflicted cells.

:P

Originally Posted by spuriousmonkey

The formulation of the question indicates that the situation presumes the presence of other cells besides the afflicted cells.

:P

Yes that is excactly what i was assuming. Sorry for not pointing that out.

I've been offline for a while. I just wanted to nitpick. :wink:

I've been online forever and I want to destroy fluffy things.

Originally Posted by Thermaltake

Are some mutations reversable? If there is, name some?

DNA repair systems correct mutations if they are detected before replication of the mutation. A commonly cited example is correction of thymidine dimers; individuals lacking the repair system have the condition xeroderma pigmentosum. Generally, 'mismatch repair' can also be accomplished, and the correct base is determined by virtue of the fact that the 'older' DNA strand is more heavily methylated than the newer strand.

I vaguely recall that some rare experimental systems have demonstrated the correction of mutations after replication of the mutation but cannot recall the specifics, and may be incorrect.

Originally Posted by free radical

Originally Posted by Thermaltake

Are some mutations reversable? If there is, name some?

DNA repair systems correct mutations if they are detected before replication of the mutation. A commonly cited example is correction of thymidine dimers; individuals lacking the repair system have the condition xeroderma pigmentosum. Generally, 'mismatch repair' can also be accomplished, and the correct base is determined by virtue of the fact that the 'older' DNA strand is more heavily methylated than the newer strand.

I vaguely recall that some rare experimental systems have demonstrated the correction of mutations after replication of the mutation but cannot recall the specifics, and may be incorrect.

How do the dna then know it has a bad mutation?

1) Do it have the original intact dna saved somewhere, if so where is it?

or

2) Do the dna itself have a part of it with complete information, that cannot be changed?..IE the junk dna might be that complete copy of its original state, but encoded, so it cannot be changed.

or

3) Or do the faulty dna with its mutation get help from another copy of complete dna without mutation from another cell?

Do those dna's in every cell even co-operate with eachothers?

http://en.wikipedia.org/wiki/DNA_repair

Originally Posted by Thermaltake

When mutation happen in one cell, is it determined that all other cells in the body will get the mutation eventually?

Only descendant cells of the cell that mutated will have the mutation. Example would be a cell in the dividing layer of the skin. Cells it produces by division into the outer layers of the skin would carry the mutation. The mutation would go no further and will not be inherited by offspring.

Originally Posted by Thermaltake

If mutation only happen in some specific cells,
Is it because of nonliving causes, like radiation?

Radiation and various other mutagenic environmental factors may cause mutation, as may DNA replication errors caused by the slight error-prone nature of our replication machinery.

Originally Posted by Thermaltake

If mutation happens in all cells in the body,
Is it because of a virus or a bacteria, that spread the mutation?

This would be what we call horizontal gene transfer, a form of gene flow. It does occur but at a low rate. There are some parts of the human genome originally transferred from microorganisms, particularly viruses as I recall.

Originally Posted by Thermaltake

Are some mutations reversable? If there is, name some?

I'm not sure about mutations caused by external factors, but replication errors are generally picked up by our replication machinery's proof-reading function.

Originally Posted by Thermaltake

How do dna in one cell communicate with dna in another cell to tell it to mutate?

Never happens, as far as I am aware. No idea how it could.

Originally Posted by Thermaltake

Something tells me that dna has a boss. And that dna itself dont communicate with another dna in another cell.

The boss(es) of DNA are the laws of physics and chemistry.

Originally Posted by Thermaltake

Will junk dna get information only if all the other places in the dna is used up with letters?

All of DNA, including the so-called junk DNA, is composed of the same stuff. If you like, the same four letters. The sequence determines the meaning, including where coding sequences begin and end.

Originally Posted by Thermaltake

Maybe junk dna is holding the secret of mutation, or junk dna is the catalyst to the rest of the dna's evolution.

Junk DNA has functions, but this is not thought to be one of them.