The researchers were focusing on i-motif DNA, which has an interlocking structure resembling a knot, and was only confirmed to be found in living human cells in 2018.

New Twisted 'Knot' Human DNA Structure Discovered—and It Looks Nothing Like the Double Helix. Published Apr 23, 2018 at 12:58 PM EDT Updated Apr 23, 2018 at 1:53 PM EDT. By .

James Watson and Francis Crick revealed the structure of DNA — the genetic instructions in all living things — 70 years ago in the journal Nature. Watson and Crick could not have succeeded ...

A piece that aired on NPR this week about the discovery of DNA's structure neglected to mention the significant contribution of Rosalind Franklin to that scientific milestone.