Insights

Q&A with Anna Davey: Making Sense of DNA in Sexual Offence Cases

Written by Natalie Bamber | Mar 10, 2025 12:23:27 AM
 

Anna Davey, Director of Forensic Foundations International, breaks down DNA evidence, forensic concepts, and case limitations in sexual offence matters. Ahead of her presentation at Navigating Forensic Evidence in Criminal Law Matters on Friday, 21 March 2025, she shares key insights into DNA interpretation and its legal impact.

1. Your upcoming presentation will unpack DNA evidence in sexual offence cases. What are some practical takeaways attendees can expect?

Preparation! You can’t wing it. Every sexual offence case is different and the science/medicine input will be different. Take the time to speak with the scientists / medical practitioners involved.

The science/medicine is not scary, it is quite logical, although it does use another language.

Ask ‘How did the biological material / DNA get there?’

There is help out there 

2. DNA technology is developing fast. Can you highlight one key advancement or limitation that legal professionals should be aware of, and how it could impact these cases? 

The technology currently in use can detect exceedingly small quantities of DNA. Detection. This can be extremely useful but it is a two edge sword. The detection of small amounts of DNA can complicate the interpretation. 

Are there alternate explanations see:

  • R v Jama [2009] VSCA; Inquiry Into The Circumstances That Led To The Conviction Of Mr Farah Abdulkadir Jama, F H R Vincent (2010)
  • Fitzgerald v The Queen [2014] HCA 28

3. Presenting DNA evidence in court can be extremely challenging. What do you see as the biggest hurdles, and how can practitioners make complex DNA concepts easier for judges and juries to understand?

  • By understanding it themselves.
  • Let the expert explain it without interrupting.
  • By use of analogies which people can relate to.
  • Don’t get caught up the technical aspects.

4. You’ll also touch on assumptions in DNA reports. How do these scenarios come up?

An accused may suggest that the true offender was an identical twin, a sib or other biological relative. The default assumption is that this is not the case, the lab would need to be informed if this and further interpretations and calculations can be made.

The number of contributors to a mixed DNA profile.

Where relevant the victim / known consenting sexual partner may be one of the contributors.

The Australian Caucasian population database is used for the calculation of the statistics in reference to the true offender (not the accused). If the ethnicity of the true offender is known a different database may be used.

5. Finally, with new techniques emerging and existing limitations persisting, how do you see DNA evidence shaping the future of sexual offence cases and the broader field of criminal law?

DNA is not going away. Scientific and technology advancements will continue to advance the application of molecular biology (genomic DNA, mitochondrial DNA and RNA).

Forensic genealogy is a controversial field – it can provide wonderful intelligence information but at the risk of personal privacy.

Next Generation Sequencing (NGS) or Massive Parallel Sequencing MPS) allows scientists to examine significantly more areas of the DNA, which in turn provides significantly more information including data regarding inherited physical characteristics.

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Anna DaveyDirector, Forensic Foundations International


Anna Davey B.Sc. (Hons) (Melb), M.Sc. (Melb), Grad Dip Legal Studies (UNE), Grad Cert Pub Sec Mgmt (Flinders), Cert IV CBT (Barton). In 1988, Anna was employed by the then State Forensic Science Laboratory as part of a small team formed to introduce DNA profiling to Victoria for criminal casework. By 1994, she was Team Leader and had developed an interest in education and training in forensic science. In 1997, Anna moved from casework to lead the ‘Quality Management, Education and Information Services’ team. From 2000 – 2004, Anna held the position of Executive Officer of the National Institute of Forensic Science and in 2004, was appointed Deputy Director. In 2008, Anna Davey founded Forensic Foundations International, a specialised service providing flexible fit-for-propose forensic program for expert and legal practitioners. These services involve training, consultancy, case review and auditing. Anna operates in all areas of the forensic sciences, focusing on quality management, the interface between science and the legal system, and forensic science based R&D. She brings an unequalled depth of knowledge and experience to these subjects. Anna is the immediate past Vice President (Australia) of the Australian and New Zealand Forensic Science Society (ANZFSS) and is Secretary of Victorian Chapter of the Australian Academy of Forensic Science.