3D DNA Double Helix
How to use the 3D DNA viewer
- Type or paste a DNA sequence (A, C, G and T; up to 80 bases are drawn). Each base pair becomes a rung: green A pairs with red T, blue G with yellow C.
- Turn on Show bases to label each half of every rung, and turn off Spin to rotate the helix yourself.
- The length, number of turns, GC content and reverse complement are worked out from the sequence; the Reverse Complement and DNA Stats tools do the same for sequences of any length.
Frequently asked questions
What are the dimensions of DNA?
B-DNA, the usual form, is 2 nm across, rises 0.34 nm per base pair and makes one full turn every 10.5 base pairs, or 3.4 nm. A human cell's 3 billion base pairs would stretch about 1 metre.
Why are there two grooves of different sizes?
The two backbones are not opposite each other across the helix but about 150° apart, so the gap between them is wide on one side (the major groove, 2.2 nm) and narrow on the other (the minor groove, 1.2 nm). Proteins that read DNA mostly bind in the major groove, where the edges of the base pairs are exposed.
Why does GC content matter?
G–C pairs are held by three hydrogen bonds and A–T pairs by two, so GC-rich DNA is more stable and melts at a higher temperature. The guide on GC content explains what it affects.
It says WebGL is turned off.
The 3D view needs WebGL, which every current browser has. It can be switched off by hardware acceleration being disabled in the browser settings, or by a very old graphics driver. Turn hardware acceleration on, or try another browser.
Is anything uploaded?
No. The simulation is drawn by your own browser with WebGL; nothing is sent anywhere, and it keeps working offline once the page has loaded.