What are the Uses and Examples of DNA Profiling?

• Identity: To find out if a person is related to you.
• Twins: It is difficult to tell at birth whether twins are identical or fraternal. Identical twins share the  same genetic material, whereas fraternal twins are no different from individual siblings born at different times.
• Immigration: Some visa applications may depend on proof of relatedness
• Criminal justice: Comparing the DNA profiles of suspects to offender samples can help to identify the real criminal. DNA profiles can then be kept on a database.


Examples of Cases Making Use of DNA Profiling
• Three men were wrongly jailed for the 1988 murder of a Cardiff prostitute named Lynette White. The case was finally solved when the police discovered a fresh DNA sample under layers of paint where she had been killed. It was a partial match with a teenager on the national DNA database. However, it turned out to be a close relative, who was eventually jailed for life in 2003.
• Stefan Kiszko was jailed for 16 years, for the murder of schoolgirl Lesley Molseed in 1975. He was released when sperm samples were found on her clothing, which could not belong to him since he was infertile. The police reopened the case in 1999 and matched the DNA profile to Ronald Castree, who was later convicted and jailed for 30 years in 2007.
• 15-year old Linda Strait was abducted, raped and strangled. Her body was discovered floating in the Spokane River on 27 September. Arbie Williams was a suspect as he committed similar offenses just months after Linda Strait’s death. Investigators lacked technology until March 2003. Arbie Williams, already 61-years-old, was convicted as the DNA profile matched with his blood sample.
• In 1983, 15-year-old schoolgirl Lynda Mann was found raped and murdered in the Narborough area. Forensic scientists found a semen sample taken from her body was found to belong to a person with type A blood and an enzyme profile that matched only 10 per cent of the adult male population. With no other leads or forensic evidence, the murder hunt was eventually wound down.

Three years later, Dawn Ashworth, also 15, was found strangled and sexually assaulted in the same area. Police recovered semen samples from Dawn's body that revealed her attacker had the same blood type as Lynda's murderer. The prime suspect, a local boy called Richard Buckland, who revealed after questioning, previously unreleased details about Dawn Ashworth's body. Further questioning led to his confession, but he denied any involvement in the first murder of Lynda Mann.

Convinced that he had committed both crimes, Leicestershire police contacted Dr Alec Jeffreys at Leicester University, who had developed a technique for creating DNA profiles. Dr Jeffreys compared semen samples from both murders, against a blood sample from Richard Buckland, and proved that both girls were killed by the same man, but not by him. The police contacted the FSS to verify Dr Jeffrey's results and decide which direction to take the investigation. Richard Buckland was exonerated of murder through the use of DNA profiling. Leicestershire police then undertook the world's first DNA mass intelligence screen that took 6 months to complete. All 5000 adult males in 3 villages were asked to volunteer and provide blood or saliva samples. Blood grouping was performed and DNA profiling carried out on the 10 per cent of men who had the same blood type as the killer. However, no profiles matched the profile of the killer and it seemed that all possibilities had been exhausted.

However, the investigation took a strange twist when a year later a woman overheard her colleague, Ian Kelly, bragging that he had given his sample whilst masquerading as his friend, Colin Pitchfork. Pitchfork, a local baker, had apparently persuaded Kelly to take the test for him. Pitchfork was subsequently arrested and his DNA profile was found to match with the semen from both murders. He was eventually sentenced to life imprisonment for the two murders in 1988. 

Lesley Molseed [CASE 2]

Stefan Kiszko [CASE 2]

Ronald Castree [CASE 2]

Source(s):
• http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/DNA_Profiling
• http://www.telegraph.co.uk/news/uknews/law-and-order/5010003/Sean-Hodgson-Police-re-examine-cases-using-DNA-profiling.html
• http://nitro.biosci.arizona.edu/courses/EEB195-2007/Lecture07/Lecture07.html