Biology 9700 · AS & A Level · Principles of genetic technology
Principles of genetic technology — practice question
In 1984, geneticist Alec Jeffreys developed a DNA testing method called DNA profiling, which gives a DNA banding pattern on a gel. This banding pattern, or profile, is unique to every individual. DNA profiling is useful in police forensic investigations to catch criminals. Since 1987, police in many countries have taken and kept DNA from crime scenes to build DNA profiles, which they then compare with the DNA profiles of criminal suspects.
(a(i))[2]
DNA at a crime scene may come from hairs and small traces of blood, semen and saliva. Explain why PCR may be needed before crime-scene DNA can be profiled.
(a(ii))[2]
Explain why electrophoresis gives a DNA banding pattern on a gel.
(b(i))[2]
Suggest why the police tactic of matching crime scene DNA against the GEDmatch database was so effective.
(b(ii))[2]
Explain why GEDmatch is an example of bioinformatics.
(b(iii))[2]
The police’s first successful conviction made possible by GEDmatch was reported widely. Some journalists and broadcasters felt that the GEDmatch website ought not to have been used by the police in this way. In the days after the report, the number of citizens who decided to upload their DNA data to GEDmatch rose from 1500 to 5000 a day. Comment on the social and ethical issues raised by this first successful conviction.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “crime scene DNA may be found in very small or tiny quantities” …