The rungs of the DNA ladder are made of specific base pairings, so I chose complementary colors on the color wheel (blue and orange are also complementary) in an attempt to apply basic color principles to help reinforce color coding. Instead, I ran smack into the red/green juxtaposition.
So as medical illustrators, we try to apply basic principles in art, whether it comes to layout and design principles or color theory to help teach scientific concepts. In the above, a typical layout concept is using a zoomed-out version of an image to orient the viewer as to where the magnified view in the insert originated. Further, I used complementary colors to associate the base pairs that specifically link to each other. The blue-colored bases will always and only pair with orange, and the red will only and always pair with green.