It is a ‘hot’ topic in the forensic field: predicting someone’s appearance based on DNA from a blood sample, for example. ‘We can already predict if someone has blond hair, blue eyes and a light skin color. And approximately how old someone is,’ says Dr. Athina Vidaki, researcher at the Department of Genetic Identification. Thanks to a new test, smoking habit prediction can be added to that list.
The test the researchers developed looks at the so-called methylation markers. These are reversible changes to the DNA that everyone accumulates throughout life. This can happen, for example, through smoking or drinking alcohol, or through certain eating or sports habits. With these methylation markers, the researchers can predict whether a person currently smokes or has smoked in the past. They publish their findings in the scientific journal Forensic Science International: Genetics.
With the current 13 markers, the scientists can distinguish between smokers, non-smokers and ex-smokers. ‘If we add more and better markers to the model, we might also be able to read out how many cigarettes someone smokes per day or how many years ago someone quitted smoking,’ Vidaki explained.
The thirteen markers had previously been discovered by the Rotterdam scientists. Now the method and analysis can be further developed towards a potential application in forensic practice. The researchers see the DNA test for smoking primarily as a springboard for similar ways to predict other lifestyle habits from DNA, such as long-term alcohol use.
Interestingly, 8 of the 13 markers for smoking also correlated with age. ‘This proves that we are looking at complex systems. Perhaps it is not enough to analyze lifestyle habits in isolation. In the future, we will have to look more at the relationship between factors. For example, if we know that smoking affects your biological age, we can factor this into our prediction of offender characteristics.’
The research group also noticed that some of the markers are associated with genes responsible for the breakdown of nicotine and caffeine. They would like to explore further how this works. Vidaki: ‘The question is whether smoking also influences caffeine breakdown, or whether smokers happen to drink coffee more often than non-smokers.’ The connection with certain diseases, such as lung cancer, also needs further investigation.
Vidaki understands that her research may raise concerns and questions about privacy. This conversation needs to happen, she believes, even though her research is still in its infancy. ‘We can also see whether someone smokes on camera footage. So, how private is that information? But at some point, we can possibly also deduce from your DNA what environment you live in and what your socioeconomic status is. Then, it starts to get more sensitive.’