Skip to main content
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit

Updates regarding government operating status and resumption of normal operations can be found at

Separating the Sequencing Products: Transcript

The DNA molecules produced during the sequencing reaction are separated from each other by a process called electrophoresis. DNA molecules are negatively charged. The sequencing machine sets up an electric field; all the DNA moves through a porous gel toward the positive electrode. The gel acts like a sieve; shorter DNA fragments move more quickly through the holes of the gel than do larger DNA fragments.

Last Reviewed: March 29, 2012