What Does the Future Hold for Forensics?

Since the late 1980s forensic DNA typing has undoubtedly been developed as a powerful tool in police investigations for identifying perpetrators of crime or missing persons, via the analysis of autosomal, Y-chromosome or mitochondrial DNA markers. But is this all that we can expect from forensic genetic testing? Certainly not!

As a result of vast scientific and technological advancements over the last few years, the field of forensic genetics is developing fast. Hence, we expect that a wide range of new methods and technologies will soon be added to the next-generation forensic DNA toolkit. Which are these methods?

The panel discussion at ISHI 30, led by Athina Vidaki of Erasmus University Medical Center, will feature highly recognized experts who will present some of the most promising forensic science topics and technologies likely to be introduced in the coming years; more specifically in the fields of microbial forensics, forensically relevant body fluid/tissue identification, forensic DNA phenotyping and genetic genealogy.

Firstly, microbial communities can reveal answers to important questions risen during forensic investigations; for example, by examining microbial succession during the decomposition of a dead body we can estimate the time since death, in others words the post-mortem interval. How accurate is this microbial clock of death?

Researchers at Colorado Mesa University are looking to prove that microbes are predictably found at certain times during the decomposition process. Doing so would allow crime scene investigators to rely on this “microbial clock” to help estimate time of death, and potentially the cause.

Currently, investigators rely on the postmortem interval, or estimates of the time since death, to begin to determine what happened to a victim and to authenticate a potential suspect’s alibi. Factors contributing to the postmortem interval include activity on the victim’s credit card, when they were last seen alive, and the state of the body. In certain cases, insect species found on the body can be a clue as well, but it’s not possible to rely on insects alone.

The term “microbial clock” originated from Jessica Metcalf, a microbial ecologist and evolutionary biologist at Colorado State University who leads the FIRS project. In 2010, she decided to shift from using DNA to study Ice Age mammals to working with ancient humans, specifically understanding their gut microbes by studying feces.

During her research, Metcalf thought it wise to gain knowledge on the microbes involved in decomposition. In a study completed in 2013, Metcalf was able to show that microbial successions were consistent across different human bodies and different seasons, even when accounting for seasonal temperatures. Metcalf’s work should allow forensic investigators to uncover how long ago a person had died, to within two to four days, by swabbing and sequencing the microbes that exist on and around the body.

Also, forensic transcriptomics have shown great capacity to reveal tissue-specific patterns, that can be used to provide valuable ‘source level’ information for the police. Can the issue of inter-individual gene expression variation be solved by the inclusion of more tissue-specific mRNA markers in targeted messenger RNA-based sequencing methods?

In the video below, Joana Antunes of Florida International University describes how forensic laboratories may soon be able to use methylation markers in DNA to determine body fluid type without destroying the sample collected.