STR analysis on perforating FMJ bullets and a new VWA variant allele

Abstract

In three separate shooting incidents involving multiple gunshots, two FMJ bullets and one bullet fragment found at the scene (one from each case) were investigated for the presence of biological material from the victim after perforation. The surface of the missiles, which did not show obvious tissue traces when examined under a macroscope, was swabbed. PCR typing of up to five STR loci was performed on the small amounts of DNA extracted, which were seen below the detection limit of the slot blot quantification in one case. Nevertheless, individualisation of cellular material from the perforating projectiles was successful in each of the three cases presented. Consequently, identification of the victim wounded by a perforating bullet can reliably be achieved if contamination or removal of evidentiary material by improper handling is prevented. This technique is especially useful in cases where more than one person has fired a gun because the bullet carrying DNA can be linked to the firearm by investigation with a comparison microscope. As a by-product of this investigation, a variant allele 14 (14+4) at the VWA locus was detected.

Further sequence and length variation at the STR loci HumFES/FPS, HumVWA, HumFGA and D12S391

“…Allele 16 completes the series of alleles possessing complete tetrameric repeats (15,(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) 2) which were previously described [6]. As all interalleles are of low frequency we suggest one of the more frequent alleles 22.2 or 23.2 as a parent allele for the generation of the other alleles showing an incomplete repeat.…”

“…The existence of these allelic variants is very uncommon and unexpected in this population [24]. The only variant allele 15 reported so far derived from a Turkish Caucasian individual [21]. Therefore not only the variant allele 13 but also the variant allele 15 described in this paper have to be considered as new variants in this population.…”

“…The HumVWA locus is classified as a compound STR locus consisting of two different repeat motifs TCTA and TCTG [12] and most VWA alleles (13,(15)(16)(17)(18)(19)(20)(21)(22) follow the consensus repeat structure TCTA (TCTG) 4 (TCTA) n [7]. As shown in Fig.…”

“…The third type of variation was observed in the majority of alleles 14 (138 bp) and exceptional alleles 12 (130 bp) and 15 (142 bp)[7,13,18,21].…”

Persistence of biological traces in gun barrels—an approach to an experimental model

“…They hypothesised about the possibility of connecting a bullet with an individual target that had been hit by it by analysing the individual target's DNA recovered from the bullet [2]. Also, in a 1997 study, Karger et al were first to analyse human victim DNA retrieved from three penetrating bullets that had been recovered from a crime scene and they succeeded in identifying the victims based on short tandem repeat (STR) typing results from the collected DNA [3]. Two more recent studies introduce and analyse methods to recover DNA from firearms and ammunition to identify the individual that handled them [1,4].…”