Detection of subpicogram quantities of specific DNA sequences on blot hybridization with biotinytated probes

Abstract

A sensitive method for detecting biotinylated DNA probes on dot and Southern blots is describedwhich is based on the principle outlined by Leary et al (1). This system has two main components: detection of biotinylated DNA by a two-step procedure with streptavidin and poly(alkaline phosphatase); and blocking background with Tween 20. 32fg and 80fg of λ phage DNA was detected on dot and Southern blot hybridizations respectively. 150fg of β-globin was detected on Southern blots of genomic DNA. This method is fast, reproducible and can detect single copy genes in 0.25μg of human genomic DNA on Southern blots. © 1985 IRL PRESS Limited.