When I was restudying biology a few years ago, it was making me a little crazy trying to understand the structural geometry that gives rise to the major and minor grooves of DNA. I looked through several of the standard textbooks and relevant papers. I certainly didn't find any good diagrams or animations.

So out of my own frustration, I drew this. It's a cross-section of a single base pair, as if you are looking straight down the double helix.

Aka, picture a double-strand of DNA as an earthworm. If one of the earthworms segments is a base-pair, and you cut the earthworm in half, and turn it 90 degrees, and look into the body of the worm, you'd see this cross-sectional perspective.

Apologies for overly detailed explanation; it's for non-bio and non-chem people. :)

https://www.instagram.com/p/CWSH5qslm27/

Anyway, I think the way base pairs bond forces this major and minor grove structure observed in B-DNA.

For anyone wondering: https://www.mun.ca/biology/scarr/MGA2_02-07.html

Maybe they were depicting RNA? (probably not)

when a human does it, its style! when ai does it, you cry about your job.

And yet still manages to be 4MB over the wire.