Junk DNA is large sections of DNA that appears to have no function.  Over 95% of the human genome, at one time, has been labeled as Junk DNA and currently still 50% of the human genome are still considered Junk DNA.

Essentially Junk DNA is portions of DNA for which there are a high frequency of sequence change, a random genetic drift with no apparent outcome.

Scientists found a protein that allows sections of Junk DNA to be cut and pasted within the genetic code, a process referred to as DNA transposition.  DNA transposition can have an important positive effect on the performance of neighboring genes.

For example, in humans, a rearrangement of antibody genes can help the immune system target infection more successfully.

Researchers will now study this process of DNA transposition further in a hope to harness this ability to shift DNA for the benefit of genetic therapies.

Dr. Julia Richardson said, “By forming a picture of the enzyme that causes DNA to shift and discovering how this works, we understand more about how these proteins can be adapted and controlled.  This may one day enable genes to be pasted into cells exactly where they are needed – which could be of enormous benefit in developing gene therapies.”

http://www.sciencedaily.com/releases/2009/09/090921134702.htm