Defferences between wave length 254nm, 302nm, 365nm? - UV transluminator (May/19/2009 )

Does anyone known about differences in three wave lengths: 254nm, 302nm and 365nm?

I am investigating to buy a new UV transluminator and is recommended to buy it with UV length 302nm. Is 302nm show clearly DNA and RNA bands on agarose gel?

How is about 254nm and 365nm?

254 nm is pretty useless for imaging DNA, except by shadowing. It will rapidly degrade DNA so that it is unclonable.

305 nm excites Ethidium bromide well, but also can damage DNA reasonably quickly.

365 nm is not as good as 305 nm in terms of exciting EtBr, but is far less damaging to the DNA.

You might also want to think about the "dark reader" blue illumnation, which is reasonably harmless to DNA.

Rule of thumb: the longer the wavelength, the less energy there is in each photon, and the less damaging it will be to DNA.

Less energy also means that the emission will be weaker due to the mechanism by which fluorescence works.