Cold case detectives are investigating a homicide that took place 30 years ago. In reexamining the evidence, they find a tiny spot of blood on the victim’s clothing that was likely left by the murderer. The DNA in the blood has partially degraded over time. What technique(s) would the blood lab technicians use in their examination of this tiny, degraded blood sample? Select all that apply.
A) They would use a restriction enzyme and DNA ligase to make recombinant DNA from this sample.
B) They would use PCR to amplify the DNA.
C) They would use reverse transcriptase-polymerase chain reaction (RT-PCR) to determine the genes expressed in this DNA.

PCR or Polymerase Chain Reaction, using a thermostable enzyme, Taq Polymerase. It is a molecular biology technique, whose objective is to obtain a large number of copies of a DNA fragment of interest, starting from a minimum. It is done in a thermal cycler.

This technique serves to amplify a DNA fragment; after amplification it is much easier to identify with a very high probability, virus or bacteria causing a disease, identify people or do scientific research on amplified DNA.