University of Bristol
Wellcome Trust
Recommended by:
Society of Biology
PEEP for Physics & Ethics at GCSE

Applications of DNA Profiling

Inheritance: are you family?

When STRs or restriction fragments are tested in DNA profiling, they usually occur in pairs. The profile shows a band from the mother and a band from the father because the repeated sequences or DNA fragments inherited from the parents are of different lengths. Occasionally only one band appears because both fragments or sequences in a pair are of the same length.

When the DNA profile of a child is compared to the profiles of its genetic parents, it is possible to match the bands in the child’s profile with those in either the mother or father's profile.

Forensics: were you at the scene of a crime?

Forensic scientists compare DNA samples taken at crime scenes with DNA samples from victims and suspects to help solve crimes. They simply look for a match in the positioning of the bands in the two DNA profiles.

Some ethical questions:

Who should see your DNA profile? DNA profiles can provide insights into many intimate aspects of a person and their family such as susceptibility to a particular disease and the identity of their genetic parents. This increases the potential for genetic discrimination by government, insurers, employers, schools or banks.

What should a scientist do if they find that a DNA profile, produced for an entirely separate reason, proves that the person someone thought was their father isn’t?

How certain does a jury need to be that the patterns in DNA profiles linking someone to a crime scene match? Scientists presenting profiles at court have given odds ranging from 1 in a few hundred thousand to 1 in millions that they have come from the same person.

Need help with calculating odds?

  Thought experiment

Should UK Police aim to build a national database of DNA records for everyone found guilty of a serious crime?

If no, why not? Can you justify your answer?

If yes, should they include the DNA records of everybody sampled in the process of investigating a current crime in order to build up a national resource to use in identifying the person responsible for a future crime?


Can you find out what DNA records the police currently maintain?


Next: Pharmacogenetics


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Activity DNA Fingerprinting Challenges

Try these online interactive DNA profiling exercises from

 Biotechnology Australia