What technique is used to separate larger DNA fragments?

Pulsed field electrophoresis is the technique specifically designed for the separation of large DNA fragments, typically ranging from about 50 kb to several megabases in size. This method involves applying an electric field that periodically changes direction, allowing large DNA molecules to migrate through a gel matrix more effectively when compared to standard gel electrophoresis, which is generally more suitable for smaller fragments. By using different angles and durations of the electric fields, pulsed field electrophoresis enhances the resolution of large fragments, making it particularly valuable for applications such as genomic mapping, characterization of complex genomes, and analyzing large plasmids or bacterial artificial chromosomes.

Gel electrophoresis is a broader category that can separate DNA, RNA, and proteins but is primarily effective for smaller fragments. Southern blotting is a technique used to detect specific DNA sequences after separation, while the polymerase chain reaction is used to amplify DNA but does not involve separation of fragments based on size. Therefore, pulsed field electrophoresis stands out as the appropriate choice for separating larger DNA fragments.