I have a crackpot theory related to this that I don’t take too seriously, but I think about it sometimes anyway. Much of developmental biology depends on gene regulation networks and chemical gradients. Encoding complicated information into the brain would therefore require a large number of regulatory switches. If each of these switches needs its own protein, then not much complexity can fit in the genome. So the crackpot theory is that some of the non-coding DNA is actually what contains most of the information. RNA can control gene expression, so it’s not totally crazy. Of course, we somehow have to make this consistent with the amount of sequence conservation in non-coding DNA.
EDIT: Just to explain further, the crazy part of the theory is not that the non-coding DNA is doing stuff, it’s that there is a fairly general and modular system for specifying patterns of neuron connections, where adding a new circuit or drastically modifying an existing one can be done only by modifying non-coding DNA, without needing to touch coding DNA at all.
I think “gene expression is significantly affected in systematic ways by non-coding DNA, and RNA is a vector by which this happens” is completely mainstream in genomics, and has been for a pretty long time?
Yeah, there’s a spectrum there from things that are reasonable to things that are unreasonable, and I think I didn’t include the most unreasonable parts. I will edit.
I have a crackpot theory related to this that I don’t take too seriously, but I think about it sometimes anyway. Much of developmental biology depends on gene regulation networks and chemical gradients. Encoding complicated information into the brain would therefore require a large number of regulatory switches. If each of these switches needs its own protein, then not much complexity can fit in the genome. So the crackpot theory is that some of the non-coding DNA is actually what contains most of the information. RNA can control gene expression, so it’s not totally crazy. Of course, we somehow have to make this consistent with the amount of sequence conservation in non-coding DNA.
EDIT: Just to explain further, the crazy part of the theory is not that the non-coding DNA is doing stuff, it’s that there is a fairly general and modular system for specifying patterns of neuron connections, where adding a new circuit or drastically modifying an existing one can be done only by modifying non-coding DNA, without needing to touch coding DNA at all.
I think “gene expression is significantly affected in systematic ways by non-coding DNA, and RNA is a vector by which this happens” is completely mainstream in genomics, and has been for a pretty long time?
Yeah, there’s a spectrum there from things that are reasonable to things that are unreasonable, and I think I didn’t include the most unreasonable parts. I will edit.