DNA Electrophoresis Using Thiazole Orange Instead of Ethidium Bromide or Alternative Dyes.

DNA gel electrophoresis using agarose is a common tool in molecular biology laboratories, allowing separation of DNA fragments by size. After separation, DNA is visualized by staining. This article demonstrates how to use thiazole orange to stain DNA. Thiazole orange compares favorably to common staining methods, in that it is sensitive, inexpensive, excitable with UV or blue light (to prevent sample damage), and safer than ethidium bromide. Labs already equipped to run DNA electrophoresis experiments using ethidium bromide can generally switch dyes with no additional changes to existing protocols, using UV light for detection. Blue-light detection to avoid sample damage can additionally be achieved with a blue-light source and emission filter. Labs already equipped for blue-light detection can simply switch dyes with no additional changes to existing protocols.

Thiazole orange as an everyday replacement for ethidium bromide and costly DNA dyes for electrophoresis.

DNA gel electrophoresis is a standard tool of biochemistry and molecular biology laboratories. The common dye ethidium bromide suffers from toxicity concerns and requires the use of damaging ultraviolet light. We observe that exposing plasmid DNA to a UV transilluminator for only 1 s results in detectable loss of colonies following transformation, suggesting rapid accumulation of DNA damage. SYBR Safe, a commercial product, is marketed as a safe alternative to ethidium bromide and has excellent sensitivity with nondamaging blue light, but suffers from prohibitively high costs. We show that thiazole orange, the parent compound of SYBR Safe, is an excellent, simple, and inexpensive alternative to these dyes. It is excitable with safe blue light or UV light, with DNA detection limits in agarose gels similar to ethidium bromide and SYBR Safe (1-2 ng/lane). Thiazole orange safely allows the use of nondamaging blue light at the same cost as ethidium bromide.