This has to be true over geological time doesn't it? I know about "junk" DNA but as I understand it much of that probably is functional, though it's not expressed in protein. Natural selection is what stops DNA from becoming non-functional. If a goven sequence stops working that means either something breaks and the organism gets sick(er) or a workaround is developed or redundancy is used up. If something is non-functional there are many more ways for it t be non-functional in the same way than one so mutation is far lesss constrained than if it's expressed so over the very long run we should expect non-coding regions to disappear though there will always be quite a few.
Over the extremely long run regions of the genome that have no biological function should disappear, no?
Over the extremely long run regions of the genome that have no biological function should disappear, no?