Our most basic DNA Helix shows all the important details including complementary base pairs & at 450mm (18") tall. Makes a great gift for middle school science minded students.
The image has been produced as a stereo pair; click on the image for an enlarged version & then cross your eyes to see it in 3D.
Note that the relative size of the major & minor grooves is exaggerated for effect. For more precise models, see our 12 base pair DNA model; DNA double helix model, 17 base pairs or 36 base pair Big Bang Theory DNA Model.
This makes it quite useful for teaching the theory behind dna forensic fingerprinting, especially the touch DNA method. This technique flows from a refinement of the PCR (polymerase chain reaction) which now only requires 7-8 skin cells to identify someone.
Although the actual base pair sequences analyzed for DNA fingerprints are much longer than 22, students will appreciate that because the touch DNA method relies on 13 specific DNA locations, the overall chance of misidentification is very small.
I just gave my first one away as a gift, so I had to buy another one and assemble with my kids again! In addition, a colleague here at our Boston biotech loved assembling the one he bought with his son. Great value and continually instructive.