In human cells, scientists find DNA that looks like a twisted knot instead of a double helix


Biology textbooks may be due for a rewrite.

For the first time, scientists have detected a DNA structure inside living human cells that looks more like a four-stranded knot than the elegant double helix we learned about in school.

The tangled shape, known as an i-motif, had been seen before in the lab, but few researchers expected it to occur in human cells.

The new work shows not only that i-motifs do indeed exist in human cells, but that they may be quite common.