Image: Law & Order: SVU - Detective Benson stands accused based on fake DNA evidence

Detective fiction routinely uses DNA technology as a plot device. So much so that that the “CSI effect” has been blamed for distorting the criminal justice system. Victims of crime and jurors have unrealistic expectations about the role of evidence in criminal investigations and criminals now know all too well how to protect themselves from leaving evidence at crime scenes. This is not helped by fiction sometimes depicting techniques that are feasible but far-fetched. A case in point is the crime drama, ‘Law and Order: Special Victims Unit‘. In 2009 an episode, ‘Perverted’, a detective was framed for murder. A DNA specialist secretly collected genetic material, amplified it using PCR, mixed it with someone else’s blood (after the original DNA had been removed) and left it at a murder scene. The detective is eventually cleared when analysis of the DNA showed that it had been generated in vitro. While this depiction of a procedure to detect the artificial DNA was fanciful it does depict an actual technique. So what are some of the ethical implications of this technique? And do these go far beyond fiction?

In terms of the ‘hard science’, the method used in the ‘Law and Order’ episode was analysis of DNA methylation. Over time the DNA in our bodies is changed by the environments we inhabit and the activities we pursue. This can happen by adding or subtracting methyl groups to our DNA. These changes are stable over time. What we do in life impacts on our genetic material and these changes not only stay with us but also can theoretically be passed onto our children and grandchildren, although the possibility of transgenerational changes are highly controversial. The study of these changes is known as epigenetics. It is a field of study that promises to have profound implications not only for epidemiology but also for the forensic criminal investigation, the law courts, the insurance industry, privacy and environmental justice.

In terms of links between science and crime, forensic investigation has a long history of using DNA fingerprints to place ‘suspects’ at scenes of crimes. But analysis of genetic variation, in the absence of a suspect, can provide little more than the probability of basic external characteristics (e.g. sex, ethnicity, eye and hair colour). Analysis of methylated genes offers a new window on the past behaviours of anyone who has left a DNA residue behind at a crime scene. For example, it should be possible to determine if someone is a smoker or even if they have smoked in the past. Identifying patterns of alcohol or drug consumption are potentially possible. Such information could substantially narrow the range of possible suspects. The technique also offers the possibility of solving the evil twin trope, beloved of crime fiction and soap operas.

Few would argue with anything that might improve the clear up rate serious crimes, but there are complex moral and ethical dilemmas about its wider use. While the field of epigenetics could advance epidemiology by providing useful exposure indicators, it also raises a number of serious ethical issues. Positively, epigenetics does offer the potential for some real, empirical detective work. This technique has the potential to not only understand the ill-health associated with environmental exposure to toxic chemicals, pollutants and pesticides but it could allow disadvantaged groups to prove that these exposures have occurred in the past. The possibility of identifying intergenerational effects poses serious challenges for notions of historical equity, as well as environmental and health regulation and law. It also opens the possibility of greatly expanding intergenerational litigation. How legislation and regulation responds to these challenges is yet to be determined.

Perhaps the most obvious issues raised by epigenetics are to do with issues of privacy and confidentiality. That genetic material can contain an imprint of past behaviours and exposures could be exploited by employers, the insurance industry or even health services. Most of the current genetic privacy laws in Europe and America do not currently take account of the risks that analysis of epigenetic data may pose. This needs to be addressed in legislation.

The combination of advances in epigenetic analysis combined with other technological developments presents an unsettling picture. Advances in the development of complex paper-based diagnostic tools, the so called lab on a stamp, offer the prospect of providing cheap disposable tests that can be used away from laboratory settings. Such diagnostic tools have the potential to be ‘game changing’ inventions for simpler and cheaper testing in the developing world. But they also raise a future scenario where someone applying for a job or insurance will routinely have a small sample of blood or saliva taken. This could be analysed by an untrained employee to instantly reveal past indiscretions, behaviours or chronic medical conditions that an applicant may have.

Epigenetics offers a number of truly exciting potentials, for example: understanding and addressing inequities in hazard and environmental exposures; as novel epidemiological markers; and by enhancing forensic investigations. Yet at the same time there is a need to ensure that this innovative technology does not lead to novel forms of discrimination. These are the far more pressing issues that ethicists and legislators need to address, rather than the grandiose and unrealistic representations of epigenetic science we see in detective fiction.