Investigating sex determination through MALDI MS analysis of peptides and proteins in natural fingermarks through comprehensive statistical modelling

Abstract

In the last decade, Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS) has proven to be a valuable analytical tool in forensic research as it can detect and map molecular information of forensic relevance in trace evidence such as fingermarks and hair. The first published proof of concept demonstrating that it was possible to differentiate males and females from the peptide and protein content of their fingermarks was published in 2012. In that work, MALDI MS was used in Profiling mode (MALDI MSP) to quickly obtain spectral profiles of ungroomed marks.

Exploring the problem of determining human age from fingermarks using MALDI MS-machine learning combined approaches

“…The collection of natural fingermarks for age determination studies has been described by Heaton et al , 6 in accordance with approved Sheffield Hallam University ethics application ER17244422. The same set of data processed to determine the sex of an individual has been used here with no further experimental laboratory work aside from reprocessing and repurposing the dataset, which was analysed using a number of statistical approaches to explore in depth the challenges and the potential of determining human age from the molecular composition of a fingermark.…”

“…Three spectra per individual were processed according to the Heaton et al , 6 method. In short, three marks were obtained per donor, each consisting of the summed total of three individual mass spectra acquisitions from three distinct matrix spots per fingermark.…”

“…To this end, following an initial proof of concept study, 5 Heaton et al reported comprehensive statistical modelling to determine the sex of an individual exploiting the differential peptide and small protein profiles detected by matrix assisted laser desorption ionisation mass spectrometry (MALDI MS) from natural fingermarks. 6 This approach led to the best performing model/classification system yielding sex determination with 86% of accuracy of prediction. Whilst this prediction power does not permit a suspect exclusion from investigations, it does enable the adoption of this approach for triaging crime scene marks, prioritising those to investigate, as part of the forensic strategy.…”

Imaging mass spectrometry: a new way to distinguish dermal contact from administration of cocaine, using a single fingerprint

“…For example, there is growing evidence that fingerprints can be used to convey information about the donor, such as use of medication [1][2][3][4][5] and gender. [6][7][8][9][10][11][12] There is also growing evidence to support the concept of using a fingerprint to provide information concerning the circumstances of depositionso-called "activity level information". [13][14][15] Meanwhile, in its latest World Drug Report 2020, the United Nations Office on Drug and Crime (UNODC) reports that as of 2018 approximately 5.3% (or 269 million people) of the global population aged 15-64 had used illicit drugs in the previous year.…”

Application of MALDI MS imaging after sequential processing of latent fingermarks

“…Such technologies have emerged particularly from spectroscopy and mass spectrometry (MS) which can enable both detection of a vast range of fingermark constituents (profiling capability) and their visualisation (imaging capability) onto the ridge pattern. These capabilities provide the opportunity to potentially narrow down the pool of suspects by providing lifestyle and personal information on the owner of the mark (such abuse/handling of drugs, medications, blood groups and sex [3][4][5][6]) whilst linking this intelligence to the biometric information retrieved from the reconstruction of molecular images of their fingermarks [7][8]. These techniques have been previously reviewed and advantages and drawbacks have been outlined [8][9][10].…”