Bromophenol blue and xylene cyanol

[TytoAlba95]

Bromophenol blue and xylene cyanol are used as a tracking dye. But do they interact with the DNA as EtBr does?
After doing some research I got to know that they do not bind to the DNA but migrate independently at different speeds; bromophenol blue migration rate is equivalent to 350 - 400bp while Xylene cyanol is equivalent 3 - 4Kbp of DNA.

So they will be basically staining or it is right to say migrating with the DNA fragment of a particular size. The choice of tracking dye hence will vary with the DNA fragment of interest.

Am I correct?
https://www.researchgate.net/post/Why_DNA_loading_Dye_contains_Bromophenol_blue_and_Xylene_cyanol_FF

 

[Ygggdrasil]

Yes, that's correct though how they migrate through the gel compared to DNA depends on the percentage agarose in the gel. People use these dyes so it is easier to track the progress of one's gel electrophoresis experiment.