 Susumu Ohno coined the phrase “junk DNA” to describe these nonfunctional swaths of DNA.They include introns, genetic sequences that are removed after transcription into mRNA and thus are not translated into proteins; transposable elements that are mobile fragments of DNA, most of which are nonfunctional in humans; and pseudogenes, nonfunctional DNA sequences that originated from functional genes.The share of the human genome that may be considered “junk” remains controversial.