DNA alternatives?

[JulioSalinas]

Hello,
As a non-bioligist I have watched many tv programs about evolution and DNA but for some reason I have never heard anything about life that wasn't fundamented on the traditional DNA-structure. I would think that the principle of evolution goes beyound the DNA structure and if so there should be other competing models.

Does such non-DNA life exists on earth?

I would be glad if anyone could comment on this and maybe give me a few references so I could read some more about it. In advance thanks

[canalon]

Well the short answer is that as far as we know it there is no life form that is not based on DNA, or completely dependant on it (RNA viruses).
The genearl principles of evolution would certainly apply to any non DNA based life, but we have yet to find any.
One of the reason might be that if there was any it has been wiped out by the current descent of LUCA (our Last Unknown Common Ancestor)

[JulioSalinas]

Really, that is kind of weird isnt it?
I mean DNA might be succesfull but logically it can't stop the evolutionary process from still happening at the lowest level right? Eventhough alternative life structures might be struggleling to be succesfull we should register their presence nevertheless.

I wonder why we dont hear more about this fascinating issue...anyone got any links to this topic or related articles?

[canalon]

Well the problem is that now, pretty much every niche has been very successfully filled by plenty of different species. While on the other hand any new life form would be quite inefficient at using resources at the beginning. They do not have chances to prosper at all.

A new cuddly toddler as no chance against a nature that is basically "all red in tooth and claw" and had a few billion years headstart.

[JulioSalinas]

I see your point that DNA has been refined but every concept must have gaps leaving room for alternatives.

Another question that is equally interesting is why those alternatives never had any success in being established when DNA itself was weak and under development? Or maybe they had but dissapeared after a while.

[JackBean]

you're right, they may have appeared, but the DNA-based life was stronger and better and vanished the other forms. But these are only guesses with no proofs.

[JackBean]

the problem also is, that we know only the DNA-based life, thus we don't know for what else to look. That's even problem, when searching life on other planets.

[JulioSalinas]

Yeah, I guess it could be so strange that we might not see it at first glance. I have always speculated that dynamic is one of the most important requirement for life. If the enviroment is very dynamic where particles interact much then it would be a good place for life to develop. Usually very hot places have alot of dynamic so eventhough we might find it unthinkable, a place like the sun could have some kind of life evolving.

Well thats naturally pure speculation for now.

[JackBean]

dynamic may be fine, but there must be some sustainable chemistry, which for sure on sun is not