How to untangle knotty DNA

Knots have been removed from DNA by stretching the molecular strands with an electric field. The work was done by researchers in the US, who have quantified how stretching causes a knot to move along DNA so that it vanishes when it reaches the end of the strand.  The experiment also gives insights into how nanoscale knots can become jammed on a strand. Understanding how to untangle knots in molecular strands could improve DNA sequencing technologies and lead to better polymer-based industrial processes.