Chain - termination DNA sequencing

    Replication of the DNA strand at the top with a reaction mixture of standard dNTPs and one ddNTP (here, ddATP) produces a set of DNA fragments in which chain growth has been terminated at each position where a ddA has been incorporated.  Four separate reactions with each of the four ddNTPs produces a complete set of fragments that differ by plus or minus one nucleotide.

Figure 2000 by Griffiths et al. ; text 2013 by Steven M. Carr