The Development and Application of Random Match Probabilities to Firearm and Toolmark Identification

The field of firearms and toolmark analysis has encountered deep scrutiny of late, stemming from a handful of voices, primarily in the law and statistical communities. While strong scrutiny is a healthy and necessary part of any scientific endeavor, much of the current criticism leveled at firearm and toolmark analysis is, at best, misinformed and, at worst, punditry. One of the most persistent criticisms stems from the view that as the field lacks quantified random match probability data (or at least a firm statistical model) with which to calculate the probability of a false match, all expert testimony concerning firearm and toolmark identification or source attribution is unreliable and should be ruled inadmissible. However, this critique does not stem from the hard work of actually obtaining data and performing the scientific research required to support or reject current findings in the literature. Although there are sound reasons (described herein) why there is currently no unifying probabilistic model for the comparison of striated and impressed toolmarks as there is in the field of forensic DNA profiling, much statistical research has been, and continues to be, done to aid the criminal justice system. This research has thus far shown that error rate estimates for the field are very low, especially when compared to other forms of judicial error. The first purpose of this paper is to point out the logical fallacies in the arguments of a small group of pundits, who advocate a particular viewpoint but cloak it as fact and research. The second purpose is to give a balanced review of the literature regarding random match probability models and statistical applications that have been carried out in forensic firearm and toolmark analysis.     

Defending the scientific foundations of the firearms and tool mark identification discipline: responding to recent challenges

Recent challenges have brought the discipline of firearms and tool mark identification to the forefront in recent court cases. This article reviews those challenges and offers substantial support for the scientific foundations of the firearms and tool mark identification discipline. A careful review of the available literature has revealed that firearms and tool mark identification is rooted in firm scientific foundations, critically studied according to the precepts of the scientific method culminating in the Association of Firearms and Toolmark Examiners' Theory of Identification. Firearms and tool mark identification has been validated in a manner appropriate for evidence of the kind to be expected in firearms and tool mark examinations. Proficiency tests and error rates have been studied and can provide consumers of the disciple with a useful guide as to the frequency with which misidentifications are reported in the community using appropriate methodologies and controls. As a result, the primary issues in recent challenges do not invalidate the firearms and tool mark discipline as a science nor should it detract it from its admissibility in a court of law.     

Allele frequencies of 15 autosomal STR loci in the Iraq population with comparisons to other populations from the middle-eastern region

Allele frequencies for the 15 autosomal STR loci included in the AmpFlSTR((R)) IdentifilerTM PCR Amplification Kit panel from Applied Biosystems (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, TH01, TPOX, CSF1PO, D19S433, D2S1338, D16S539) and several statistical parameters were estimated from a sample of 103 unrelated individuals, mostly Shia and Sunni Arabs, living in most of central and southern Iraq provinces. We compared the allele frequency spectrum detected in the Iraqi population to allele frequencies from 11 other data sets from published studies of individuals from Turkey, Iraqi-Kurdistan, Saudi Arabia, Arab Emarates, Oman, Iran, Syria, and Jordan. Significant global differences in allele frequencies were detected in 9 of the 11 comparisons following sequential Bonferroni corrections. Comparisons with the two independent panels from Saudi Arabia were not significant after applying Bonferroni corrections, however, low P-values (P<0.05) associated with these two contrasts nonetheless suggested that at least slight genetic differences between populations may exist.     

Haplotype analysis of 17 Y-STR loci in a Japanese population

We analyzed 17 Y-STR loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS438, DYS439, DYS456, DYS458 and DYS464a/b/c/d) in 252 Japanese males using three multiplex PCR typing systems. Two variants were found at DYS385a/b. A total of 244 different haplotypes were observed, of which 239 were found in single individuals. The haplotype diversity for the 17 loci was 0.996.     

Measurement Uncertainty When Estimating the Velocity of an Allegedly Speeding Vehicle from Images

Abstract: Sometimes the question arises whether it is possible to estimate the velocity of a speeding car recorded by closed circuit television cameras. By estimating the travelled distance of the car between two images and the time elapsed, estimation of the velocity is rather straightforward. However, to quantify the corresponding measurement uncertainty, the data analysis becomes more involved. The article describes two approaches as to how to derive the measurement uncertainty. In the first method, distance and timing are estimated separately, and the two uncertainties are combined to derive the measurement uncertainty for the velocity. For this, a frequentist and a Bayesian approach are described. In the second method, the measurement uncertainty for the speed is derived directly using validation recordings of a car driving by at known speed. The choice which method to use depends mainly on the length of the path that the car has travelled.     

An STR database on the Volga-Ural population

This work develops a reference STR database on the Volga-Ural population, Russia, comprised of 640 individuals that were sampled from eight ethnic groups (Finno-Ugric Mari, Mordva-Moksha, Mordva-Erzja, Komi-Permjak, and Udmurt, and Turkic-speaking Bashkir, Tatar-Mishary, and Chuvash) and typed with 10 autosomal STR markers: TH01, CSF1P0, FGA, vWA, D3S1358, TPOX, D16S539, D8S1179, D13S317, FES. The groups differentiate in allele frequencies, and therefore we computed θ-values between allele frequencies in each ethnic groups and those in the database as a measure of their differentiation. Nevertheless, the Volga-Ural ethnic groups form a relatively compact cluster that greatly deviate from the Romanic Moldovans and the Turkic Yakuts, taken for comparison, and are closer to the Slavic Russians, Belarusians, and Ukrainians, although significantly differ from those as well.     

Developing STR databases on structured populations: The native South Siberian population versus the Russian population

Developing a forensic DNA database on a population that consists of local ethnic groups separated by physical and cultural barriers is questionable as it can be genetically subdivided. On the other side, small sizes of ethnic groups, especially in alpine regions where they are sub-structured further into small villages, prevent collecting a large sample from each ethnic group. For such situations, we suggest to obtain both a total population database on allele frequencies across ethnic groups and a list of θ-values between the groups and the total data. We have genotyped 558 individuals from the native population of South Siberia, consisting of nine ethnic groups, at 17 autosomal STR loci of the kit packages AmpFlSTR SGM Plus и AmpFlSTR Profiler Plus. The groups differentiate from each other with average θ-values of around 1.1%, and some reach up to three to four percent at certain loci. There exists between-village differentiation as well. Therefore, a database for the population of South Siberia is composed of data on allele frequencies in the pool of ethnic groups and data on θ-values that indicate variation in allele frequencies across the groups. Comparison to additional data on northeastern Asia (the Chukchi and Koryak) shows that differentiation in allele frequencies among small groups that are separated by large geographic distance can be even greater. In contrast, populations of Russians that live in large cities of the European part of Russia are homogeneous in allele frequencies, despite large geographic distance between them, and thus can be described by a database on allele frequencies alone, without any specific information on θ-values.     

保障流动人口合法权益 促进厦门和谐社会建设

随着厦门市经济发展和社会进步,流动人口劳工总量呈稳步上升之势.虽然厦门市在保障流动人口权益、促进厦门和谐社会建设方面取得了显著成绩,但还存在着一些问题,为此应采取措施,保障流动人口合法权益,促进和谐社会建设.     

Analysis of 124 SNP loci included in HID Ampliseq identity panel in a small population of Rio de Janeiro,Brazil

Implementation of massively parallel sequencing platforms can bring a great contribution to Forensic Genetics field, with a great saving of time and costs, as well as allowing reliable results to be obtained from small or extremely degraded samples. The aim of this work was to analyze 124 SNP loci (90 autosomal and 34 Y-SNP) included in HID-Ion Ampliseq Identity Panel in a small sample from Rio de Janeiro state, Brazil. Samples from 12 non-related individuals were amplified with HID-Ion Ampliseq Identity Panel and sequenced on the Ion Torrent PGM platform (Thermo Fisher Scientific); genotypes were generated with HID SNP Genotyper plugin and forensic parameters were calculated with PowerStats v.12. All samples were successfully genotyped and were used to calculate allele frequencies, homozygosity, heterozygosity, random match probability (RMP) and exclusion power for all 90 autosomal SNP loci. Using the formula proposed by Budowle et al. (1996), only 4 of the 90 loci genotyped (4,4%) showed allele frequencies below the minimum required. It means that although a small set of individuals was used on this study, it may have shown a good perspective of Rio de Janeiro state allele frequencies. Among the 11 male samples analyzed, a prevalence of the haplogroup R1b of Y chromosome was observed, followed by the haplogroups E, Q and J. Such distribution reflects the results demonstrated in other studies for the population of Rio de Janeiro. All results together demonstrate the usefulness and applicability of SNP analysis on Ion Torrent PGM.