Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Schematic representation of the test DNA molecule, which contains four phased A-tracts. Only the sequence around the A-tract insert is shown in detail. The base pair at the center of the fragment is numbered 1, as indicated in the numbering scheme below the sequence.
