How well do we understand DNA?

I disagree. If the only processes acting to change DNA are the reproduction process itself, the error correction processes and mutations (of all sorts) then there is nothing to "drop" DNA but those mutations. If random most of these drop "good" as well as "junk". If it is true that the cost of carrying extra DNA is small then there will be no selection acting to get the real junk weeded out.Also remember that the original designation of junk was based on the fact that it does not code for proteins.Also we see that what are obviously broken genes are carried along for a pretty significant time. It is unlikely that these are both broken genes and of some other value (unless pure bulk is of value).I think it is true that bacteria (where there may well be a 'carrying cost' since they are smaller) do not carry as much junk.This message has been edited by NosyNed, 01-16-2005 10:51 AM

I don't see how you think this works. Just because some random mutation happens in the "junk" DNA doesn't mean it won't happen elsewhere in the DNA.It sounds like you're saying that the odds of a mutation are such and such and if one happens here it is less likely it will happen there. But the odds are so many per million base pairs. So if the coding DNA is so many base pairs long then it's chances of a really random mutation are just as great no matter what has happened in the other millions of base pairs.

Yes that is possible. However, there isn't any hint of it yet.There was (referenced elsewhere I don't have it) a study where large segements of mouse "junk" was stripped out. IIRC, the result was -- no change. The animals seemed perfectly normal.This is the type of experiment that will have to be done over generations to be sure there is no effect but it is indicative.As I noted, if there is no significant cost to carry extra DNA then there is nothing to remove it. With that the case we can expect DNA to pile up that would be really non functional.This would supply a source for new funtions with further mutations of course. It may be that this is a long term advantage that actually selects for having "junk" DNA but I'm n ot sure that can be the case.I expect the regulating parts of non coding DNA will be shown to have certain properties. I will be very surprised if those include looking just like a working gene that has had a hit by a mutation.You may continue to hope for some new discoveries in this area but I don't see it likely that it will help you. These same discoveries are very likely to further strengthen our understanding of how we and chimps evolved from a common source. You should not pin your faith on what will be found out in genetics.

Without checking back I will try to offer what might be the right translation of the above.We understand natural mechanisms which can form new genetic sequences which are expressed as proteins. That is they are both new (not in the genome of the ancestors of the individual) and correctly formed sequences (new genes) that will be transcribed to proteins.There are a number of mechanisms that can do this. Gene duplication and mutation being an obvious one.

It has already been done.Try a google on "gene therapy". It isn't working well right now but we have experimented with it.