Problem with the above is that junk DNA is not junk. Scietists do not call it that, they call it 'non-coding DNA' because they are quite aware that it does have a purpose even though it does not code for genes. One of the obvious purposes of it is the control of gene expression - when, and how much of a particular protein to make and where. Genes do not control themselves, they are just factories and do what the DNA outside of the genes tells them to do.
Some does, some has no apparent purpose at all, and is very unlikely to. (various repeating sections, pseudogenes, fossil viruses to name a few.)
Remember the LGGLO (scurvy) mutation in the great apes (including people). It's very similar to functional dna in other mammals, except for one missing base pair, which totally screws it up downstream from there.
Is it there for some unknown regulatory purpose? Evidence? Is it there to make a novel protein that only apes need? Evidence?
If it's not junk (your claim) and it would allow us to make vitamin C if just one base-pair were added (sequencing data), then the conclusion would be that it's a mutation that does something useful. But you're always claiming that doesn't happen!