Does junk DNA have a purpose?

It now seems that some of the 'Junk' is structural, helping to maintain of genes and chromosomes, and that some if it is very important for controlling how our genes work. There seem to be 'messages' coming from what was previously thought to be junk which help to control genes, turn them on and off and operate feedback cycles.There is some evidence that micro-RNA copied from 'junk' DNA may be essential in out immune system, and 'junk' DNA is now being studied for its effects in cancer.This is a quite a new field of research, so watch this space!