Gwen Fisher has posted the instructions on how to make her DNA double helix; she includes coloring the base pairs so the A, T, G, and C molecules denote an actual species. My species was limited by my bead colors! So, this is the shape only.
I found this straightforward to do. Gwen warns about tension, so I made sure to use enough — not usually a problem for me. I slightly modified her thread path. She builds the third corner and then adds the first row of beads to that side. I built corner three, then four, then back to three to add the first row of beads to the same side Gwen did. That thread path worked for me.
Here are Gwen’s instructions, which she illustrated using Doceri, a tool often used by teachers. I continued the geekiness by dragging and saving images from that video, putting them into a Word document, converting it to a PDF, and then saving it on my ereader. I think Gwen would approve. 🙂