"Junk" (or noncoding) DNA has become an icon of evolution. Evolutionary biologists maintain that because junk DNA is an imperfection, it provides incontrovertible evidence for evolution. After all, why would a Creator bother with useless materials? Numerous recent studies, however, have identified function for many types of junk DNA. This new study shows that LINE DNA, a class of noncoding DNA that can duplicate itself and movea round in the genome, plays a role in creating human diversity. As LINE DNA moves around the genome, it can alter gene expression patterns which, in turn, affect an organism's characteristics. Such functional importance of junk DNA indicates that careful planning by an Intelligent Designer, rather than undirected, random biochemical events, shaped the genomes of organisms.
Alysson R. Muotri et al., "Somatic Mosaicism in Neuronal Precursor Cells Mediated by L1 Retrotransposition," Nature 435 (2005): 903-10.
Fuz Rana, "Yet Another Use for Junk DNA"
Icons of Evolution: Science or Myth?, by Jonathan Wells