Typically, genotyping was possible with as little as 50 ng target DNA.
They are hybridized to a target DNA, which is then copied by the polymerase.
The target DNA is then washed and the labeled probes that didn't hybridize are removed.
The target DNA is then analyzed for the presence of the probe via radioactivity or fluorescence.
It is fully complementary to its target DNA (here taken from the human β-hemoglobin gene), as shown on the next line.
The end result would be a precise copy of the target DNA.
During the extension step the strands are amplified beyond the target DNA.
However, samples often contain nucleases that degrade the target DNA before it can be purified.
In doing this the inhibitors completely block the active site from binding to target DNA.
This method requires the target DNA to be broken into random fragments.