Building DNA.

• Make sure to print out one backbone piece for each base! Two backbone styles are included; one with hydrogen one without.

• A good place to start is one each of Adenine(A), Thymine(T), Guanine(G) and Cytosine(C), plus four DNA_backbones. You can add more pieces to the model later. (Use either DNA backbone model; the DNA_backbone_with_H has all the hydrogens but less reinforcement.)

• Before assembly make sure to clear all holes of support material.

Each base should snap into its backbone by gently pushing the split pin of the base into the hole of the ribose on the backbone. (not the hole on the phosphate part, that is for later).

With the base-backbone pieces assembled, you can now try make base pairs. Gently push the thin pins into the holes of a base pair. ie) Adenosine-Thymine and Guanine-Cytosine.

Next spin around the backbone parts of the base pair until they are relatively flat to the plane of the base pair and lay it on a table. One side should have a hole pointing up, the other side should have a pin pointing up. Do the same for a second base pair and lay them below the first.

You should now be able to line up the respective pins and holes of the backbones. Gently insert one backbone pin into the second backbone hole. Give a gentle twist and the hole and pin of the other side of the base pairs should line up. Print more base pairs to extend the helix.
Cap the backbone ends with the Phosphate_O and Phasphate_PO3 models.

Some notes about the build:
I find if you use an extrusion printers, you want to print the bases relatively flat to make the hydrogen-bond pins stronger. Printing narrow pins orientated vertically can be quite weak and are likely to break. I tend to find larger scaled models assemble better.
Also, take care with the alignment of the backbone pieces when extrusion printing. If you find splitting occurs when you try inserting the bases printing them in a different orientation.  Please let me know if you have any suggestions! kuiper(dot)mike (at) gmail