Electrophoresis: SingleStrain vs DoubleStrain DNA chain speed

[jhirlo]

Why does single strain DNA moves slower then double strain DNA in gel electrophoresis?

I think that it is because single strain DNA has less electrical charge than double DNA helix, and single strained binds with H bonds uncharged molecules thus increasing it’s mass.

 

[Monique]

Single stranded DNA is relatively unstable nature; in the absence of a complementary strand, the single strand may experience intrastrand base pairing, resulting in loops and folds that give the single strand a unique 3D structure, regardless of its length. A single nucleotide change could dramatically affect the strand's mobility through a gel by altering the intrastrand base pairing and its resulting 3D conformation (Melcher, 2000).

 

[jhirlo]

Please excuse my bad language.

OK, forming secondary structure… I was thinking on Single stranded DNA in denaturated gel or denaturated Single stranded DNA (urea), which can not form intrastrand bonds.