The chemist’s qualified criticism: the DNA in the logo differs from natural DNA in plants, animals or humans. Of course it is schematic, bands and rods symbolize the molecule components sugar, phosphates and bases. But the important point is: the DNA in the logo of our graphic designer is left-handed, natural DNA on the other hand is right-handed. That means: when one climbs down the cord of the logo-DNA like a spiral staircase one would go counter clockwise. In contrast to that a right-handed DNA or spiral staircase runs clockwise when climbing down.

Right-handed or left-handed? Chemists call this difference chirality. Chirality originates from the Greek word for hand “cheir”, from which the German word for surgeon, “Chirurg” (which hence means “manual worker”), also is derived from. In German one speaks of “handedness” as the hand illustrates the chirality problem very clearly. Looking at one’s right hand in front of a mirror one notices: the reflection of the right hand corresponds with the left hand but not with itself. And something that is not identical with its reflection is called chiral – that can be applied to hands as well as to many chemical molecules. Non-chiral objects are identical with their reflection like a ball or other symmetrical things.

Salt Changes the Winding Direction…

The reflection of the natural right-handed DNA is the left-handed DNA. In nature there is no left-handed DNA. But it can be created in a test tube, by mixing DNA with salt. Usually the right-handed genome molecule is stabilized in its environment by water. But the salt extracts the stabilizing water molecules – and the DNA changes direction. It turns into a left-handed DNA also called Z-DNA due to its zigzag-shape. It is not clear if this DNA variation has any biological function.


In graphic images left- and right-handed is often mixed up. Even well-known journals like Nature or Science have accidentally pictured natural DNA left-handed. Today this only happens due to inattention, especially when pictures are mirrored. However, in the past the print matrix was the problem. The picture had to be drawn on the matrix as its mirror image. Historic investigations show that in most cases snail shells were printed left-handed in the 16th and 17th century. In reality snails usually have a shell which winds clockwise.

…Aesthetics Too

Today a case like the DNA with right-left-confusability is possibly a typical problem of science journalism. Graphic designers and journalists often have to take optic aspects into account to ensure that their message is received. For scientists on the other hand accuracy and precision often are the greatest good. And in our case the natural DNA doesn’t look that good in the logo. Right? The compromise: our aesthetic change of direction is turned into a small puzzle – and maybe encourages lateral thinking. Meanwhile graphic designer and chemist at least are reconciled.