Population data for six X-chromosome STR loci in a Rio de Janeiro (Brazil) sample: Usefulness in forensic casework

This study presents data for the X-chromosome STR loci DXS7133, DXS7424, DXS8378, DXS6807, DXS7423 and DXS8377. In order to establish a database, unrelated individuals (males and females) from Rio de Janeiro were typed for the above loci. No significant differences were observed between allele frequencies in male and female samples (non-differentiation exact P values ≥ 0.156). Hardy-Weinberg equilibrium was tested in the female sample and no significant deviations were found. All six markers have shown to be highly polymorphic in our sample with gene diversities varying between 0.6797 for DXS7133, and 0.9260 for DXS8377. Pairwise linkage disequilibrium analysis did not allow discharging a possible association between DXS7133 and DXS7424 alleles in Rio de Janeiro population. Parameters of forensic interest, like PD_M, PD_F, Het_obs, Het_exp, were calculated for each locus. The high discrimination power estimated in both males and females, as well as mean exclusion chance in father/daughter duos and in father/mother/daughter trios, demonstrates the usefulness of these six markers in forensic investigation.     

Population genetic data of eight tetrameric short tandem repeats (STRs) in Casablanca resident population to use in forensic casework

The allele frequencies for eight short tandem repeat (STR) loci HUMvWA, HUMFES/FPS, HUMF13A, HUMF13B, HUMTHO1, HUMTPOX, HUMCSF1P0, HUMLPL included in Geneprint STR kits were obtained from 234 unrelated individuals in Casablanca.     

Use of subpopulation data in Australian forensic DNA casework

DNA profiling evidence presented in court should be accompanied by a reliable estimate of its evidential weight. In calculating such statistics, allele frequencies from commonly employed autosomal microsatellite loci are required. These allele frequencies should be collected at a level that appropriately represents the genetic diversity that exists in the population. Typically this occurs at broadly defined bio-geographic categories, such as Caucasian or Asian. Datasets are commonly administered at the jurisdictional level. This paper focuses on Australian jurisdictions and assesses whether this current practice is appropriate for Aboriginal Australian and Caucasian populations alike. In keeping with other studies we observe negligible differences between Caucasian populations within Australia when segregated geographically. However segregation of Aboriginal Australian population data along contemporary State and Territory lines appears to mask the diversity that exists within this subpopulation. For this reason datasets collated along more traditional lines may be more appropriate, particularly to distinguish the most genetically differentiated populations residing in the north of the continent.     

Population genetic data for 18 STR loci in Costa Rica

Allele frequencies for 18 STR autosomal loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, D16S539, TH01, TPOX, CSF1PO, Penta D, Penta E, D19S433, D2S1338 and SE33) were obtained from a sample of 191-500 unrelated individuals from Costa Rica, Central America.     

Frequencies of salivary genetic marker systems in the Japanese population and their application to forensic medicine

Seven salivary polymorphic systems were studied using whole and parotid saliva from random Japanese individuals. The gene frequencies obtained were: Pa⁺ = 0.212, Pb¹ = 1.000, Pb² = 0, Pr¹ = 0.763, Pr² = 0.237, Db⁺ = 0.051, Pm⁺ = 0.409, Ph⁺ = 0.026 and Amy₁^v = 0.013, respectively. Based on these gene frequencies, the chances for exclusion of falsely alleged fathers were calculated. The chance of exclusion on the basis of five salivary polymorphic systems was 0.305. The combined chance of exclusion utilizing only blood, serum and red-cell enzyme polymorphic systems among the Japanese population was 0.919; however, by applying salivary polymorphic systems to the calculation, the total exclusion rose to 0.944.     

四类遗传标记的检测用于混合精斑的个人识别

目的探讨综合应用常染色体STR与Y-STR、X-STR、mtDNA高变区Ⅰ序列检测四类遗传标记,提高两男性混合精液样品的个人识别率。方法使用商品化试剂盒检测混合精液样品的常染色体与X、Y染色体STR,应用单链构象多态性(single strand conformation polymorphism,SSCP)法分离两男性混合精液样品的线粒体DNA(mitochondrial DNA,mtDNA)高变区Ⅰ序列,并进行序列分析。结果混合精液样品比例超过1:10(高组分所占比例继续增加而低组分所占比例继续减少)时可以确定高拷贝者的全部四类遗传标记系统的分型。比例接近时,通过与嫌疑人检测结果的比较可获得排除或基本认定的意见。结论四类遗传标记系统的联合检测有助于提高两男性混合精液样品的个人识别率。     

Population genetic data of 15 tetrameric short tandem repeats (STRs) in Berbers from Morocco

The allele frequency distribution of 15 short tandem repeats (STR) loci contained in the AmpFlSTR Identifiler PCR Amplification Kit (Applied Biosystems), was determined in two Berber populations from Asni and Bouhria, in Central and Eastern Morocco, respectively. A total of 209 individuals were typed. No deviations from the Hardy-Weinberg equilibrium were observed for Asni at the 15 STRs loci whereas for the Bouhria samples, two loci (D5S818 and TH01) showed significant departures from Hardy-Weinberg expectations (after Bonferroni's correction). All loci are highly polymorphic and population differentiation tests showed that the Moroccan samples from Asni and Bouhria have significant differences in 4 out of 15 loci (D21S11, D7S820, D16S539 and TPOX). The aim of the study was to obtain accurate allele frequencies relevant for forensic applications. Comparative analyses between our population data and other population samples gathered from the literature are also presented.     

Population genetic data of five X-chromosomal loci in Bauru (São Paulo, Brazil)

Genetic population data for five X-STR (DXS6854, DXS7424, DXS101, DXS6808 and DXS7132) were obtained from Bauru population (São Paulo, Brazil). No deviations from the Hardy-Weinberg equilibrium were observed, with the exception of DXS101. The combined powers of discrimination in males and females were 0.99897253 and 0.99999120, respectively. These high values show the potential of this system in human identification and paternity testing.     

Using previous DNA casework data to aid decision making in the process of DNA profile interpretation

In this study, a DNA decision support tool was developed. With this tool we aim to gain insight in what actions are performed with which (types of) DNA profiles in casework, to improve decision making by DNA experts in future cases.     

Performance evaluation of automated fingerprint identification systems for specific conditions observed in casework using simulated fingermarks

Few studies have been reported on the performance evaluation of automated fingerprint identification systems (AFIS) for fingermark-to-fingerprint comparisons. This paper aims to illustrate to fingerprint examiners the relevance of evaluating the AFIS performance under specific conditions by carrying out five types of performance tests. The conditions addressed are the number of minutiae assigned to a fingermark, manual and automatic assignment of the minutiae, the finger region from which the fingermark originates, the degree of distortion in the fingermark, and the difference in orientation between fingermarks and fingerprints. In these tests, the magnitude of the influence for each condition was quantified. The comparisons were performed using a research AFIS technology with simulated fingermarks. Simulated fingermarks provide a practical way to create fingermarks for specific conditions in large quantities. The results showed that each condition influences the performance significantly, emphasizing the relevance of developing, and applying performance tests for specific conditions.     

Applicability of DNA analysis on adhesive tape in forensic casework

Adhesive tape is commonly used in crimes and is often the subject of forensic evaluation. DNA analysis of adhesive tape can provide DNA profiles of suspects. The object of this study was to evaluate the applicability of DNA analysis on adhesive tape samples in forensic casework. We retrospectively reviewed all cases involving adhesive tape or similar items received by our institute for DNA analysis during the past 11 years. From 100 forensic cases reviewed, 150 adhesive tape samples were examined. A total of 98 DNA profiles were obtained from these samples. Sixty-two of the profiles provided feasible case-relevant information. In conclusion, DNA profiling of adhesive tape samples can be useful in a variety of forensic cases.     

Population genetic data of 38 autosomal InDels in San Basilio de Palenque,the first free town in America

In order to increase the information about Indels, we report allele frequencies and statistical parameters of forensic efficiency obtained typing a sample of 114 unrelated healthy individuals living in San Basilio de Palenque – Colombia using a panel of 38 autosomal InDels. No significant deviations from Hardy–Weinberg expectations were found except in the marker rs10629077 (p = 0.0002). The present database will be useful for forensic and paternity purposes for the region studied. Moreover, these additional markers can help forensic laboratories to solve parentage testing as well as to improve the analysis of degraded DNA samples.     

Application of direct PCR in forensic casework

Direct PCR is fast becoming a popular method in forensic science due to the advantages of saving time and money in the lab while increasing the probability of obtaining substantial results has a positive rippling effect. A laboratory is able to reduce the time spent on processing trace DNA samples, which can lead to investigators receiving important information in a timely manner that may not have been possible using standard methods. This study highlights the benefits of direct PCR in forensic casework by analysing trace and touch DNA on a range of substrates and exploring the loss of initial DNA due to extraction.     

Evaluation of a semi-automated, magnetic bead-based DNA extraction method for genetic fingerprinting of forensic casework samples

In order to cope with the demanding workload for DNA profiling of forensic casework samples a concept for a semi-automated processing system was developed at the Landeskriminalamt (Office of Criminal Investigation) Baden-Württemberg, Germany [K. Vollack, et al., Implementation of a semi-automated processing system for DNA profiling of forensic casework samples, this issue]. The applied magnetic bead extraction method is based on ChargeSwitch^® Technology (CST) from Invitrogen and was established on a liquid handling workstation Freedom EVO^® 150 from Tecan.