The Internet Is Full of Incorrect Images of DNA. Here's How to Spot Them.
It's worth mentioning again and again: a tremendous amount of information on the Internet is wrong. This epidemic of incorrectness extends to the very structure of DNA: the double helix. That's right, many of the images of DNA you see online are drawn with errors. Some may have even appeared on RealClearScience! (Whoops.) What would Rosalind Franklin say?
There are three common errors. The first is the direction of the helix. The most common form of DNA (the variety that's found in almost all known life) is called B-DNA, and it twists to the right. This can be very difficult to notice when looking at a single strand of DNA, but it's easy to spot when a correctly drawn helix is directly contrasted with an incorrect one. Look which way the sugar phosphate backbones (the sides of the ladder) are pointed. When DNA is pictured vertically, they should aim up and to the right.
A second error is failing to include DNA's characteristic grooves. Look again at the image to the left. You'll notice a large gap in between the phosphate strands – a major groove – followed by a smaller one – the minor groove. Many illustrators will neglect this pattern and simply draw the strands evenly spaced out.
The final common mistake that mangles otherwise decent images of DNA is the number of base pairs per 360 degree rotation of the helix. There should be ten, but all too often the "rungs" of the DNA ladder are drawn in without thought. The incorrect image below appears to have 48 basepairs per turn! That's way too many!
Armed with this information and now fully aware of this deoxyribonucleic injustice in plain sight, what will you do? Cancer researcher and former MIT professor Thomas D. Schneider took it upon himself to document and expose all of the unique cases of incorrect DNA imagery on the Internet. He has found 823 infractions dating back to 1964.
You don't need to embark on that sort of crusade, but at least keep in mind – and perhaps share with your friends – how to spot the false images out there. DNA is essential to nearly all life as we know it, so let's at least draw it correctly!