Determining SNPs and demographic variables that impact level one fingerprint pattern

Publication Type:
Thesis
Issue Date:
2022
Full metadata record
The current forensic use of fingerprints is for identification purposes and requires a reference sample for comparison to any unknown fingermark. Features of individual ridges can be used for identification however in combination they create overall level one fingerprint patterns (arches, loops and whorls). Past studies have indicated that level one patterns may occur at different frequencies between biogeographical ancestries (BGAs) and ridge density (the number of ridges within a defined area) may indicate the sex of an individual. This research aimed to represent the level one fingerprint pattern and ridge density frequencies of the Australian population which was previously largely unknown and assess the association of pattern and ridge density with BGA, sex, hands, fingers, and genetic markers. By assessing these associations, fingerprint expert’s conclusions based on experience could be supported by statistical data and a new avenue of investigation could be unlocked from fingerprint evidence. The BGA, sex, hands, fingers or genotype of the depositor could be predicted for fingermarks that do not return a match in any database. A total of 828 volunteers donated their fingerprints and self-declared BGA. Of the 828 volunteers 515 people also donated their DNA. The fingerprints were classified using the National Crime Information Center (NCIC) classification system. Goodness of fit tests, multinomial logistic regression and general estimating equations were utilised for association of ancestry, sex, hands, and fingers with the pattern and ridge densities. Associations between fingerprint patterns and genetic markers were investigated for five genetic models. Statistical analyses revealed several fingerprint patterns occurring at significantly higher and lower frequencies than expected for BGA, sex, hands and fingers. Significant differences were also found amongst ridge densities (radial, ulnar, and proximal positions) for all independent variables, however further investigation showed that proximal and ulnar positions produced dissimilar results to right and left positions, indicating this characteristic would be limited in its usefulness in forensic casework. In 207 people of European and Middle Eastern BGAs over 60 SNPs were significantly associated with fingerprint patterns and four genetic loci of interest were located on two distinct areas of chromosome six, an area on chromosome one and an area on chromosome 11. The hypothesis that non-coding regions and epigenetic regulation are causative of fingerprint development was tentatively supported. These results provide additional and novel evidence that frequencies of level one fingerprint pattern and ridge density differ between BGAs, sexes, fingers and hands.
Please use this identifier to cite or link to this item: