Jumping 'Junk' DNA May Fuel Mammalian Evolution: Scientific American

"Tiny, jumping bits of DNA are looking less like genomic junk and more like significant players in mammalian evolution, according to a new analysis.

Researchers have uncovered more than 10,000 short stretches of what may be functional DNA in parts of the human genome with no obvious role—the so-called junk DNA that makes up 95 percent of the genome. The segments appear to be fragments of transposons, pieces of DNA capable of copying themselves and inserting into new locations, up to millions of times."