Forensic Application of Pollen DNA Barcoding

Pollen grains have been used in many of types of casework such as missing persons, robberies, drug trafficking, and even homicides since 1959. The rationale behind pollen as a trace evidence relies on the contact and wind transport from localized plant species in the location of an individual.

The flora of a location will be represented to some extent by the contribution of each species to what is known as an assemblage either on clothes or in dirt and dust on shoes or clothing. This assemblage is unique to a geographical location. While its use is common in the U.K., New Zealand, and Australia, the U.S. has seen great success in utilizing forensic palynology even though overall use is scarce. The current approach to forensic palynology is mainly relying on microscopy, either optical or electronic (SEM). The practitioner needs to identify species in the assemblage using their unique morphological properties. Once each grain is identified, the composition of the assemblage can then provide an indication of the location at which this evidence was. This tedious task requires the expertise of trained palynologists, who are in decreasing number in the USA. Academic research worldwide has shown varying genomic expression via DNA-barcoding that can be used to identify pollen without the need for visual microscopic measurements. This approach considers that the biochemical composition of a pollen grain is species dependent and can provide unique signatures. The goal of this project is to introduce DNA-barcoding as a non-destructive analysis tool for forensic palynology by characterizing pollen assemblages down to the species level through its genetic code. The project described in this proposal will consist of three parts: 1. A non-destructive protocol will be designed to obtain plant DNA from pollen grains/spores. 2. Sequence samples that are not readily available. 3. Create a high-throughput sequencing (HTS) method for quick pollen analysis and classification. This project will provide the forensic community with a genomic characterization study of pollen grains for classification and define the protocol to extract this information for use by forensic practitioners.

Note: This project contains a research and/or development component, as defined in applicable law," and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). ca/ncf