An appeal to some undiscovered function for the DNA is surely at least as
much an appeal to a gap as is the claim that we know it isn't useful.
Actually, there is positive knowledge that these regions of the DNA are not
functional, rather than ignorance. The extreme variability of spacer
regions, for example, shows that the sequence is not important, yet the
sequences of organisms thought to have recent common ancestors are similar.
There aren't significant morphological gaps or biochemical gaps between
humans and other primates. This state of affairs is not necessary for us
to function.
David C.