The 800 genetic markers studied, described as 'Junk DNA' are also known as 'microsatelites'
and can vary a great deal between individuals, and can tell a great deal about a persons identity and history, according to the number of repeated segments.
I'm sure they'll find a better name for junk when they discover how it fits into the gene sequence. I have trouble imagining it is there without having a function, or even an effect, but we still have a lot more to learn about DNA than we'd like to admit. Still, it could be like saying there is a reason for fingerprints besides identification. (Maybe grip?)