RESUMEN
Objective To explore the causes of twisted or tailed DNA bands in agarose gels after electro-phoresis .Methods Prestained and poststained methods were employed to exam 3 kinds of DNA marker bands in agarose gel with GeneGreen and Ethidium Bromide ,respectively .Results Three kinds of DNA marker bands in agarose gel with 1:10000 and 1:5000 concentration of GeneGreen showed obvious distortions and trailing phenomena compared with the same concentration of Ethidium Bromide w hen the prestained method was used for electrophoresis ,which were improved when the poststained method was used in agarose gel with GeneGreen and Ethidium Bromide ,respectively .Conclusion Nucleic acid dye GeneGreen can affect the quali-ty of DNA bands in agarose gel electrophoresis .When the quality of DNA itself ,agarose gel quality ,electro-phoretic fluid quality and voltage are excluded ,the quality of nucleic acid dye should be taken into considera-tion if the bands twisting or tailing occurs when the DNA nucleic acid electrophoresis is carried out by pres-tained method .The quality of DNA electrophoresis bands can be improved by using poststained method or re-placing nucleic acid dye .