An often repeated claim, but untrue. We have a pretty good understanding of large parts of junk DNA, how it got there and what it is, and know that most of it r

An often repeated claim, but untrue. We have a pretty good understanding of large parts of junk DNA, how it got there and what it is, and know that most of it really is junk. That being said, only around 2% of the human genome is coding, with perhaps another one or two percent having known no coding function. And estimates of functional DNA is somewhere around 8% of the genome. So, most functional DNA is still unknown.