A new advance in DNA sequencing indicates that inferences can be drawn from pollen to help solve crimes. This falls within the little developed field of forensic palynology.
One of the few facilities in the world with a palynology laboratory is located at Texas A&M University. Here some of most pioneering developments in the field have been put forward.
The origin of the science began, according to Biotechniques, when Dr. Vaughn Bryant was contacted after the terrorist attacks on 11 September 2001, focusing on this particular crime and then moving on to illegal drug imports. This led to other activities based around counterterrorism, explosives and identifying criminals.
The way this is possible is due to the ubiquity of pollen and the great variation in types of pollen. There are approximately 380,000 different types of pollen grain. Identifying different pollens found on surfaces, clothing and so on assist with understanding the point of origin.
Pollen
Pollen is the male fertilizing agent of flowering plants, trees, grasses and weeds. Pollen also happens to be a major allergen that triggers seasonal allergic rhinitis (or hay fever). Pollen levels are variable, dependent upon weather conditions such as wind and humidity. Bee pollen is a mixture of flower pollen, nectar or honey, and bees’ digestive enzymes.
New scientific approach
Forensic palynology sets out to prove or disprove a relationship among objects, people, and places that may pertain to either criminal or civil cases. This is possible because pollen can pinpoint where a person or object has been. This is something theoretically possible on a global scale or down to the level of different parts within a single garden, based on the presence of distinctive pollen assemblages.
The analysis of pollen can additionally reveal the time of year when a particular object picked up the pollen.
Examples used in trials could show, for example, whether a particular individual that the police are suspicious of was or was not involved with a specific crime, through identifying where the suspect has been – a biological track and trace system.
The downside is that such studies tend to be expensive and very time consuming, with results taking weeks to process. Hence, palynologists are generally only requested for an investigation as a last resort.
An opportunity for AI?
Much of the pollen identification process remains reliant manual methods. One possibility is creating a computer based, machine learning method to identify pollen types. However, given the range of different types of pollen, this remains some way off from realization.
Not every law enforcement agency accepts pollen analysis as evidence. In the U.S., the submission of pollen evidence would need to meet the Daubert standard (a rule of evidence regarding the admissibility of expert witness testimony, based around the legal acceptance of a scientific method).
However, there are signs of growing acceptability of the method and if computations can be advanced, the time-to-result should be significantly decreased.
