Forensic Science International: Genetics Supplement Series最新文献

Touched items at crime scenes are frequently analysed to help link suspects to crimes, for example, Touch DNA is collected from victims’ clothes in cases such as sexual assault, homicide, theft etc. Tape lifting is the preferred collection method of choice for trace DNA from clothes, fabric items and porous surfaces such as paper, therefore this study investigated the impact of deposition area and time on Touch DNA collected from fabric using minitapes. The amount of Touch DNA collected from the fabric was significantly affected by deposition area (p < 0.05), time (p < 0.05) and the interaction between the deposition area and time (p < 0.05), with the quantity of DNA collected decreasing over time. Also, the buttocks area of the trouser compared to the chest area is more prone to friction from an activity like repeatedly sitting on different surfaces which reduces the amount of Touch DNA available. In conclusion, it is more effective to collect trace DNA from victim clothes as soon as possible after the crime is committed.

When handling ammunition for gun loading, epithelial cells from the hands can become adhered to the metal surface, and this trace is a potential source of DNA. This work aimed to compare the efficiency of three DNA extraction methods from fired cartridge cases from three different types of firearms: a 12-gauge shotgun, a point 40 S&W pistol, and a 7.62 mm rifle. Nine volunteers were involved in this study handling 42 pieces of ammunition overall. The unfired ammunition was handled by a known good donor, and we used this data for comparison. DNA profiling was carried out with EZ1 DNA Investigator Kit for EZ1 Advanced XL automated DNA extraction, QIAmp DNA Investigator kit for a non-automated silica-based membrane column method, and direct lysis protocol for a non-automated in-house one. Samples were collected with 0.5 × 0.5 cm pieces of FTA filter paper moistened with distilled water. Quantiplex Pro RGQ kit and Fusion Powerplex 6C were used for genotyping samples. QIAmp DNA Investigator method resulted in the best number of alleles recovered for both conditions tested, both unfired and fired ammunitions: 77 % vs. 19.3 %, followed by the automated extraction (28.6 % vs. 4.3 %) and lysis protocol (0 % vs. 3.9 %). Degradation data from fired cartridge cases were 27 % for column method, 50 % for lysis protocol, and 87 % for EZ1 kit. Kruskal-Wallis test for mean DNA concentration from these samples returned p < 0.05, and Dunn’s multiple comparison test indicated a significant difference between calibers 0.40 S&W and 12-gauge shotgun from lyses protocol method. We did not detect any other significant differences on the test. The 12-gauge shotgun cartridge cases resulted in a high number of alleles overall (56.8 %). The numerous steps for DNA extraction and purification in the column method may explain its better performance. Although the results obtained indicate that all methods be used for DNA extraction from this type of evidence, the silica-based membrane column method appears to be more efficient.

In this study a total of n = 832 autosomal DNA profiles from Southern Africa are analysed using the GlobalFiler™ STR panel. The dataset includes South Africa (SA) profiles (n = 541) produced by Ristow et al. 2016 and includes newly generated data for SA Sepedi (n = 96) and Lesotho populations (n = 195). For the newly generated (n = 291) genotypes, we report a large degree of rare and novel variation. This included (n = 7) off-ladder allele variants and (n = 7) TPOX tri-alleles. We report forensic summary statistics and genetic diversity parameters. Expected heterozygosity and observed heterozygosity ranged between (0.7– 0.9) with SE33 as the most polymorphic and TH01 the least. For SA and Lesotho genotypes the combined match probability was (1.13 ×10^-24 and 6.035 ×10^-24) and the combined paternity index (1.4 ×10⁹ and 2.44 ×10⁸) respectively. The power of exclusion (0.9999) was similar for each dataset and no significant departures from Hardy-Weinberg equilibrium (HWE) were observed after Bonferroni correction. Population comparisons were performed by MDS and neighbour-joining and population structure inferred by STRUCTURE and DAPC unsupervised clustering.

The regulatory HERC2 SNP, rs12913832, is strongly associated with blue and brown eye colour. However, eye colour in heterozygous rs12913832 individuals is observed to vary greatly. Missense mutations in OCA2, such as rs1800407 and rs74653330, are associated with lighter eye colour in some but not all heterozygous rs12913832 individuals. Determining the physical linkage of these variants might help to further explain eye colour variation. So far, experimental haplotyping of these variants has been challenging because the genomic distance between them (∼ 135 kb) exceeds the fragment lengths produced by commonly used DNA isolation kits. The aim for this study was to explore novel methods for long distance haplotyping to assess associations between OCA2-HERC2 haplotypes and eye colour. DNA was isolated from frozen blood samples collected from Norwegians that are known to be heterozygous for both HERC2 rs12913832 and OCA2 SNPs, either rs1800407 (n = 23) or rs74653330 (n = 17), using the newly commercially available Monarch® HMW (heigh molecular weight) DNA Extraction Kit (New England BioLabs_inc). We successfully isolated DNA fragments up to 210 kb, which were long enough to haplotype OCA2-HERC2 loci by droplet digital PCR (ddPCR). Three haplotypes were observed in the study population: rs12913832:A-rs1800407:T in 22/23 individuals, rs12913832:A-rs1800407:C in 1/23 individuals and rs12913832:A-rs74653330:T in 16/16 individuals. As expected, all individuals with the rs12913832:A-rs74653330:T haplotype had intermediate to blue eye colour. However, the rs12913832:A-rs1800407:T haplotype was observed in both blue and brown-eyed individuals, suggesting more research is needed.

Formalin-fixed paraffin-embedded (FFPE) tissue blocks are commonly used in the field of pathology and forensic pathology as a source of histological slides. For postmortem kinship analysis or identification, DNA can be extracted from blocks with specialized kits. However, when an STR profile should be generated from single microscope slides, the removal of the coverslip and the limited sample size poses unique challenges. We aimed to test the effectivity of agitated xylene incubation to dissolve the mounting material to facilitate the coverslip removal. DNA extraction tests were performed on 5- to 7-year-old histological slides. Xylol was used to dissolve the mounting medium to facilitate cover slide removal, one set of samples was shaken during incubation, and the other set was left still. It was found that shaking the sample while bathed in xylol decreased the incubation time from three days to two days. Agitation not just reduced the processing time but increased the quality of acquired STR profiles: on average 30% more alleles were detected from the shaken samples compared to the still bathed ones.

The Teilum building housing the Department of Forensic Medicine at the University of Copenhagen was renovated in 2021/22. All windows were replaced, and the heating system was upgraded. During the renovation, the usual measures to prevent PCR products from escaping the post-PCR laboratories could not be maintained, since construction workers had to move in and out of the rooms carrying tools and debris. Instead, new measures were introduced, that included 1) the construction of a changing room for the workers with immediate access to the post-PCR laboratories, 2) clothing and shoes for the workers, that should only be worn inside the post-PCR laboratories, and 3) strict limitations on the areas the workers could enter, while renovating the post-PCR laboratories. Samples were taken before, during and after the renovation to monitor the possible spread of PCR products from the post-PCR areas. Mixtures of gDNA and PCR products were detected in only three of the 303 samples. All three samples were collected from the post-PCR areas prior to the renovation began, which indicated that the renovation did not cause wide-spread contamination of PCR products.

The present work aimed to study the detection, through lateral flow immunochromatographic (LFI) tests, of saliva samples over time in three different types of fabrics, as well as, the possibility of DNA isolation and characterization from the sample tubes and the cassettes. Fifty microliters of saliva (three samples/time) were deposited in denim, cotton, and polyester. Saliva was identified by SERATEC® Amylase Test and the Crime Scene version SALIVA CS, being able to detect it up to six months of deposition, although with different band intensities. Polyester showed stronger bands than cotton, probably due to its synthetic nature, and denim, as an inked fabric, showed less band intensities. Statistical analyses confirmed significant differences among fabrics, but not over time in the same type of fabric. Total DNA from the sample tubes was successfully recovered, in contrast, from the cassettes, only polyester retrieved amplifiable DNA. These findings indicated that it is possible to recover and identify saliva up to six months after deposition, also obtaining DNA. Future research will be able to expand these results, analyzing the stability of other body fluids, and the sensitivity of lateral flow immunochromatographic tests to detect them.

Y haplogroups, defined by Y-SNPs, allow the reconstruction of the human Y chromosome genealogy. Recently, MPS based panels were introduced in the forensic genetics community for Y-SNP typing and identification of a broad range of haplogroups. The panels are based on an amplicon strategy and allow the detection of up to 15,600 Y-SNPs. The panels target up to 210,000 bps, which should be compared to the overall 8.9 Mbps comprising the unique regions of the non-recombining portion of the Y chromosome (NRY). We present an alternative approach of sequencing unique regions within the NRY using target enrichment probes and hybridization capture. A total of 359,954 probes were designed using the SureDesign software, representing 7.5 Mbps of the NRY. Library preparation and capture were performed using the Agilent SureSelect XT HS2 Target Enrichment method and sequencing was performed in a NovaSeq 6000 System. Besides individual barcodes, the method also included unique molecular barcodes for additional quality screening. The method was tested on admixed South Americans that carry a Y chromosome of haplogroup Q. We successfully identified novel variation that could potentially help refining haplogroup Q phylogeny.

On February 22nd, 2021, a landslide on the Italian coast caused the collapse of an old cemetery. About 370 coffins tumbled and more than 200 fell into the sea. 333 groups of unidentified human remains were found: 140 decomposed bodies and 193 bags of commingled skeletal remains. The Medical Staff of Legal and Forensic Medicine was involved for analyzing the remains in order to identify and bury them. The remains involved belonged to people who died between the end of the XIX century and 2017; all were interesting by advanced transformative phenomena. For the identifications, new forms, based on the Interpol DVI ones, were created. Information was collected by relatives through a specific antemortem form. Relatives’ information and post-mortem data were compared: 19 body were identified thanks to secondary methods (like object in the bury, dresses, medical devices). 147 bone samples (long bones and teeth) were collected for the genetic analysis. Among the 77 relatives eligible for a genetic comparison, 66 gave consent to DNA swab for collection and genetic typing. Currently, after 48 samples DNA analysis (STRs and Y-polymorphism) 12 remains were identified, 21 presented a profile suitable for comparison but without attribution, and 7 did not return a comparable profile caused by stochastic effects. 31 subjects have been identified and the genetics analysis are still in progress. The Cemetery collapse shows that every disaster requires a tailored approach.

Birds of the Psittacidae family belong to one of the groups with the most negative impact from wildlife trafficking, which has consequences beyond removing these species from the wild. This work aimed to standardize DNA extraction techniques from blood, feathers, and eggshells of Psittacidae to molecular identification and help track the place of origin of the seized bird. Blood and feather samples from adult of the Turquoise-fronted Parrot, Amazona aestiva, individuals (n = 5) were collected, and additionally, eggshells from nests (n = 3). We tested five nucleic acid extraction techniques.DNA concentrations and purity were evaluated by fluorimetry and spectrophotometry. As a result, the extraction by phenol provided a higher concentration of DNA from blood (20 µg/ml) and feathers (0.4 µg/ml), while for the eggshells, the acetate technique was the most efficient (33 µg/ml). Polymerase chain reaction amplification of mitochondrial cytochrome B (CytB) and 16 S genes were positive for all DNA samples. We obtained favorable conditions for DNA extraction from blood, feathers, and eggshells of the Turquoise-fronted Parrot using the five DNA extraction methods tested. These protocols can be used as a reference for other species of Psittacidae, and can be applied for biodiversity and forensic studies.