Medico-legal applications of DNA fingerprinting

DNA fingerprinting is used in both criminal and civil cases

DNA in crime:

• Forensic scientists can use DNA located in blood, semen, skin, saliva or hair left at the scene of a crime to identify a possible suspect, a process called genetic fingerprinting or DNA profiling. In DNA profiling the relative lengths of sections of repetitive DNA, such as short tandem repeats , are compared with the DNA pattern obtained from the suspect's blood sample.

• In threatening letters for blackmailing or life threats. Examination of the envelop may reveal traces of saliva from licking the envelop or stamp. DNA fingerprinting can point to the suspect.

DNA in civil cases

1- Identification of paternity:

• Conventional blood tests can only exclude a man from being the father of a child. But nowadays, with DNA fingerprinting, it is possible to resolve the matter and prove beyond any doubt whether a man is or is not the father of a child. In disputed maternity, mitochondrial DNA fingerprinting is done

2. Immigration cases:

• DNA fingerprint tests are done for immigration purposes to confirm the family relationships.

3. Criminal cases:

• Any stain (blood, semen or saliva) present at the scene of a crime can be analyzed for its DNA profile and matched with the DNA pattern obtained from the suspect's blood sample.

4. Zygosity determination in twins:

• The zygosity of a pair of twins may sometimes need to be determined. Twins are either identical (monozygotic) or non identical (dizygotic).

5. In missing persons:

• It may be used in helping to identify whether objects have been handled by, or belonged to, a missing person.

6- In mass disaster:

• To help identification of people provided that reference samples are available.

Category: Forensic Medicine Notes