Kimberly Chapman has several knitted patterns of coils and helices on her website. Most of them are snakes, but…one of them is a DNA helix!
Baby’s First DNA
From the site:
“This is a knitted model of DNA, complete with GC/TA base pairs represented by orange-green bars with a pointed join and blue-yellow bars with a stepped join (because there weren’t enough stitches to make a wave or curve), replicating the standard simplified DNA model. As you can see from the pictures, it also makes a good toy insofar as it holds its shape while squished or stretched, because it is stuffed firmly with cotton balls.”