What is the use of etidium bromide in gels if dyes are used?

[appleguo]

Hi all, sorry but i need to clear a doubt. If dyes like methylene blue are used, what is the use of including etidium bromide in agarose gels?Because from what i know, etidium bromide actually can be detected by autoradiography and shows fluorescence when they intercalate bands. But if bands are shown by the blue dye, what then is the use of etidium bromide?

[sdekivit]

methylene blue is only added to follow the front when running the gel --> bands aren't shown with it.

--> then you'll have to use ethidium bromide to show DNA

[canalon]

And EtBr is detected by fluorescence, not autoradiography. You need a UV source to detect your bands. Otherwise Sdekivit gives the answer.