Patent ID: 7371520

Claim:
A method for analyzing a single nucleic acid molecule comprising exposing a single nucleic acid molecule to at least two distinguishable detectable labels present on different unit specific markers for a time sufficient to allow the detectable labels to bind to the single nucleic acid molecule, and passing the single nucleic acid molecule in flow through a diffraction-limited detection spot, thereby analyzing the single nucleic acid molecule for a coincident event using a single molecule detection system by detecting two separate and distinguishable signals from the at least two distinguishable detectable labels, wherein the single nucleic acid molecule is present at a concentration of 400 fM or greater, the coincidence event indicates that the at least two distinguishable detectable labels are bound to the single nucleic acid molecule, the coincident event is a color coincident event, and the method analyzes 20-20,000 single nucleic acid molecules per minute.