In 1984, the geneticist Alec Jeffreys invented a DNA testing technique, known as DNA profiling, that produces a DNA banding pattern on a gel. The DNA banding pattern (profile) is unique to each individual. DNA profiling can be used in police forensic work to catch criminals. Since 1987, police in many countries have collected and stored DNA from crime scenes to create DNA profiles, which they try to match with the DNA profiles of criminal suspects.

1. (a)(i)DNA at a crime scene may be obtained from hairs and traces of blood, semen and saliva. Explain why PCR may be needed before DNA from a crime scene can be profiled.[2]
2. (a)(ii)Explain why electrophoresis produces a DNA banding pattern on a gel.[2]
3. (b)(i)GEDmatch is described as 'an open data personal genomics website'. It can be used by people who want to upload their DNA data to trace their ancestors and other relatives. In 2018, police in the USA solved a large number of serious crimes. Some of these crimes had been unsolved for over thirty years. The police used GEDmatch to profile DNA taken from crime scenes and to look for matching DNA profiles. In many cases the police found partial matches to the relatives of criminals. This allowed the criminals to be identified and then charged on the basis of a complete DNA profile match. Suggest why the police strategy of comparing crime scene DNA with the GEDmatch database was so successful.[2]
4. (b)(ii)Explain why GEDmatch is an example of bioinformatics.[2]
5. (b)(iii)The first successful conviction resulting from the use of GEDmatch by the police was widely reported. Some journalists and broadcasters thought that the GEDmatch website should not have been used by the police in this way. In the days following the news, the number of citizens choosing to upload their DNA data to GEDmatch increased from 1500 to 5000 a day. Comment on the social and ethical issues raised by this first successful conviction.[2]