Random coils, electrophoretic

At low electric fields, a DNA molecule of medium size can be considered as a random coil with some degree of flexibility. Electrophoretic mobility is expressed as... 

However, three remarks concerning the effects of short wavelength modes should be made here. First, the over- and under-shoot stretching phenomena clearly point out that some intra-tube DMA modes, neglected in the BRM, are excited if the field is applied on a truly random coil DNA. This transient effect does not seem to affect the overall reptative behaviour of DNA, but may be very important in pulsed field techniques where separation is increased by coupling the external pulsed field(s) to transient effects that may affect the molecular electrophoretic mobility. 

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