Jake Buehler writes:

Imagine the human genome as a string stretching out for the length of a football field, with all the genes that encode proteins clustered at the end near your feet. Take two big steps forward; all the protein information is now behind you.

The human genome has three billion base pairs in its DNA, but only about 2% of them encode proteins. The rest seems like pointless bloat, a profusion of sequence duplications and genomic dead ends often labeled “junk DNA.” This stunningly thriftless allocation of genetic material isn’t limited to humans: Even many bacteria seem to devote 20% of their genome to noncoding filler.

Many mysteries still surround the issue of what noncoding DNA is, and whether it really is worthless junk or something more. Portions of it, at least, have turned out to be vitally important biologically. But even beyond the question of its functionality (or lack of it), researchers are beginning to appreciate how noncoding DNA can be a genetic resource for cells and a nursery where new genes can evolve.

“Slowly, slowly, slowly, the terminology of ‘junk DNA’ [has] started to die,” said Cristina Sisu, a geneticist at Brunel University London. [Continue reading…]