STEALTH, not rapid reproduction, is the key to successful junk DNA.
“Jumping genes”, or retrotransposons, are short stretches of DNA that insert copies of themselves around the genome. One of these, Alu, has undergone several bursts of copy production within the human family tree, and now makes up about 10 per cent of our DNA – without any obvious function.
Geneticists had assumed that a few vigorous Alu elements with a knack for copying hold the key to these bursts. But now that looks too simple.
One such Alu copying frenzy began 3 to 4 million years ago, giving rise…
