[entee]

A little background on one of the authors: Carlos Bustamante (there are two science-famous ones, this one is NOT the one who analyzed Elizabeth Warren's DNA test) is a pioneer in structural analysis of DNA, particularly using optical tweezers to study how DNA (and later proteins) behave. As part of that work he has been interested in how tension or compression or other perturbations propagate through the DNA helix. The longitudinal unstacking is part of that.

Full disclosure: in graduate school I worked in a lab that published a paper that contradicted some of his previous work. It was a different part of the lab so I only know the high level overview of the controversy. He's a giant in the field though.