Junk DNA
Sequencing the human genome has revolutionised the way molecular biologists look at our DNA. And junk DNA, material once thought of as irrelevant genetic waste, is becoming a focus of scientific interest, as Raghav Chawla explains
“Today, we are learning the language in which God created life,” US President Bill Clinton said on 26 June 2000. The initial sequencing of the human genome had historically been completed.1
Eight months on, two research teams published their draft versions of the sequence.23 In an article accompanying the publication in Nature, David Baltimore, remarked, “For conceptual impact, it does not hold a candle to Watson and Crick's 1953 paper describing the structure of DNA. Nonetheless, it is a seminal paper, launching the era of post-genomic science.” 45
For a long time, scientists believed that non-coding DNA was useless junk. Coined by Susumu Ohno,1516 the phrase “junk DNA” initially related only to DNA satellites but was soon used to describe most categories of non-coding DNA.1718
Junk DNA has since been shown to be much more important, however. And possibly “the amount of non-coding DNA per genome is a more valid