The basic techniques of genome sequencing are
relatively simple, and many of the procedures are
automated. Essentially, the DNA to be sequenced
(termed the template) is denatured by heat or alkali
to produce single-stranded DNA, and DNA polymerase
is used to synthesize DNA based on the nucleotide
sequence in the template. DNA polymerases require a
region of double-stranded DNA to initiate synthesis. This
is provided by adding a short single-stranded DNA
molecule – a primer, with a DNA sequence complementary
to the template DNA. The primer binds to the
template to form a short region of double-stranded
DNA, from which the rest of the template DNA is
synthesized.