Transforming single DNA molecules into fluorescent magnetic particles for detection and enumeration of genetic variations

TLDR

Biomedical research often requires detecting rare genetic variations in individual genes or transcripts. The study introduces a method to quantify such rare variations at unprecedented scale and ease. The method converts each DNA molecule into a magnetic bead carrying thousands of identical copies, enabling one‑to‑one representation that is quantified by flow cytometry; this BEAMing approach uses beads, emulsion, amplification, and magnetics. The technique can analyze millions of DNA molecules, isolate specific variants by flow sorting, and identify and quantify rare mutations in gene sequences or transcripts across populations or tissues.

Abstract

Many areas of biomedical research depend on the analysis of uncommon variations in individual genes or transcripts. Here we describe a method that can quantify such variation at a scale and ease heretofore unattainable. Each DNA molecule in a collection of such molecules is converted into a single magnetic particle to which thousands of copies of DNA identical in sequence to the original are bound. This population of beads then corresponds to a one-to-one representation of the starting DNA molecules. Variation within the original population of DNA molecules can then be simply assessed by counting fluorescently labeled particles via flow cytometry. This approach is called BEAMing on the basis of four of its principal components (beads, emulsion, amplification, and magnetics). Millions of individual DNA molecules can be assessed in this fashion with standard laboratory equipment. Moreover, specific variants can be isolated by flow sorting and used for further experimentation. BEAMing can be used for the identification and quantification of rare mutations as well as to study variations in gene sequences or transcripts in specific populations or tissues.