A completed sequencing reaction contains an array of colored DNA fragments. The shortest are the length of the primer plus one colored base. The longest fragments are usually between 500 and 800 bases long, which is when the sequencing reaction runs out of steam. The products of sequencing reactions are fed into an automated sequencing machine. Sequencing machines have become increasingly sophisticated over the last decade - running more samples, processing them more quickly, and requiring much less labor to set up.
National Human Genome Research Institute
