This project is a faithful, hands-on structural model of a short segment of DNA. Unlike the studded DNA models typically seen, this Technic model is meant to be handled, untwisted, unzipped, recoded, zipped back together, and twisted back into a double helix as often as the user likes.
At the length shown in the photos (18 base pairs), the model holds a twist of approximately 165 degrees on its own.
As a set, the model would have appeal as both a hands-on learning experience and a handsome display.
The builder would learn the modular structure of the DNA molecule and how that structure encodes genetic information first-hand. He or she would first build the backbone of alternating phosphate and sugar subunits, here represented by black pin joiners and black #1 angle connectors.
Note: The photos show black 3L friction pins holding the backbone together, but the currently produced blue ones would be fine.
The builder would then add the colored pin joiners representing the 4 nucleobases to each backbone in the order shown in the instructions. In the photos, white, orange, red, and yellow stand for the nucleobases adenosine, thymine, guanine, and cytosine, respectively.
The builder would then "zip" the two single strands of DNA together using 2L friction pins to form double-stranded DNA cross-linked by "base pairs" (pairs of nucleobases). Finally, the builder would twist the model into a double helix.
The set would include extra colored pin holders to allow the builder to change the genetic code represented by the base pair (color) sequence between the black backbones.
Since set instructions don't normally contain explanatory material, the educational information (e.g., the meaning of the pin joiner colors and the color pairing rules they should follow) would be provided as a download or in a separate booklet included in the box.
The appropriate number of base pairs would be determined by the set designers but should be a multiple of 3 to reflect the fact that the genetic code consists of a series of 3-letter words (codons) spelled in an alphabet provided by the base pairs. I'd recommend at least 18 base pairs to ensure a conspicuous twist.