Complex sentence: The gel sieves the DNA by the size of the DNA molecule, smaller molecules travel faster, except in field inversion, where it is possible to have "band inversion"-where large molecules appear to have traveled further than small molecules.
Split into simpler sentences: The gel sieves the DNA by the size of the DNA molecule, smaller molecules travel faster. In field inversion, it is possible to have "band inversion"-where large molecules appear to have traveled further than small molecules.