Population data from the New South Wales Aboriginal Australian sub-population for the profiler plus autosomal short tandem repeat (STR) loci

It is a requirement that forensic DNA profiling evidence be accompanied by an estimation of its weight, in order that the court can assign an appropriate probative value to it during legal proceedings. There are various models by which this estimation can be made, but each relies on approximations of the allele frequencies in the relevant population. This report provides the results of population genetic analyses at nine autosomal short tandem repeat (STR) loci for the Aboriginal Australian sub-population of New South Wales, Australia.     

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.     

Autosomal microsatellite allele frequencies for 15 regionally defined Aboriginal Australian population datasets

DNA profiling results presented in court must be accompanied by a statistical estimate of its evidential weight. In calculating such statistics, allele frequencies from the tested loci are required. These allele frequencies should be collected at a level that appropriately represents the genetic diversity that exists in the population. This paper reports allele frequencies and the results of population genetic testing of autosomal microsatellite profiles from indigenous Australian donors. In contrast to previous practice these data have been collated according to traditional regional boundaries rather than recently imposed State and Territory borders.     

Population data from sub-populations of the Northern Territory of Australia for 15 autosomal short tandem repeat (STR) loci

It is a requirement that forensic DNA profiling evidence be accompanied by an estimation of its weight, in order that the court can assign an appropriate probative value to the evidence during legal proceedings. There are various models by which this estimation can be made, but each relies on approximations of the allele frequencies in the relevant population. It is also important to assess relevant population genetic features of the available data. This report provides allele frequencies and estimates of common population genetic parameters for the major sub-populations of the Northern Territory of Australia genotyped at 15 autosomal short tandem repeat (STR) loci.     

DNAc: A clustering method for identifying kinship relations between DNA profiles using a novel similarity measure

After decades of refinement, DNA testing methods have become essential tools in forensic sciences. They are essentially based on likelihood ratio test principle, which is utilized specifically, by using as prior knowledge the allele frequencies in the population, to confirm or refute a given kinship hypothesis made on two genotypes. This makes these methods ill suited when allele frequencies or kinship hypotheses are unavailable. In this paper, we introduce DNAc, a new clustering methodology for DNA testing based on a new similarity measure that allows an accurate retrieval of the degree of relatedness among two or more genotypes, without relying on kinship hypotheses or allele frequencies in the population. We used DNAc in analyzing microsatellite DNA sequences distributed among 12 genotypes from normal individuals from two distinct families. The results show that DNAc accurately determines kinship among genotypes and further gathers them in the appropriate kinship groups.     

Missing persons-missing data: the need to collect antemortem dental records of missing persons

The subject of missing persons is of great concern to the community with numerous associated emotional, financial, and health costs. This paper examines the forensic medical issues raised by the delayed identification of individuals classified as "missing" and highlights the importance of including dental data in the investigation of missing persons. Focusing on Australia, the current approaches employed in missing persons investigations are outlined. Of particular significance is the fact that each of the eight Australian states and territories has its own Missing Persons Unit that operates within distinct state and territory legislation. Consequently, there is a lack of uniformity within Australia about the legal and procedural framework within which investigations of missing persons are conducted, and the interaction of that framework with coronial law procedures. One of the main investigative problems in missing persons investigations is the lack of forensic medical, particularly, odontological input. Forensic odontology has been employed in numerous cases in Australia where identity is unknown or uncertain because of remains being skeletonized, incinerated, or partly burnt. The routine employment of the forensic odontologist to assist in missing person inquiries, has however, been ignored. The failure to routinely employ forensic odontology in missing persons inquiries has resulted in numerous delays in identification. Three Australian cases are presented where the investigation of individuals whose identity was uncertain or unknown was prolonged due to the failure to utilize the appropriate (and available) dental resources. In light of the outcomes of these cases, we suggest that a national missing persons dental records database be established for future missing persons investigations. Such a database could be easily managed between a coronial system and a forensic medical institute. In Australia, a national missing persons dental records database could be incorporated into the National Coroners Information System (NCIS) managed, on behalf of Australia's Coroners, by the Victorian Institute of Forensic Medicine. The existence of the NCIS would ensure operational collaboration in the implementation of the system and cost savings to Australian policing agencies involved in missing person inquiries. The implementation of such a database would facilitate timely and efficient reconciliation of clinical and postmortem dental records and have subsequent social and financial benefits.     

Further characterization and population data for the pentanucleotide STR polymorphism D10S2325.

Pentanucleotide tandem repeat markers are interesting for forensic sciences, because they may present less stutter on the electrophoretic pattern. We focused on the analysis of the DNA sequence for each allele at the pentanucleotide STR locus D10S2325 in order to understand their structures in the human genome and to construct human allelic ladder, which is necessary for forensic DNA typing. In order to evaluate the forensic applicability of D10S2325 and to construct a preliminary database, the genotype distributions and allele frequencies in three major ethnic groups were investigated. The population samples included Caucasians (Germans), Africans (African Americans), and Asians (Chinese). A total of 520 samples from unrelated individuals was analyzed by Amp-FLP. An example of each allele and new alleles were sequenced. Allele determination was carried out by comparison with a sequenced human allelic ladder made in-house. This pentanucleotide STR provided easily interpretable results. A total of 15 alleles was found in our population samples. Three new alleles were observed and named as alleles 19 and 21 based on the number of repeat motifs, while allele 19 can be divided further into two alleles, 19a and 19 according to analysis of the sequence. No evidence of deviation from Hardy-Weinberg equilibrium was observed. In 64 confirmed father/mother/child triplets no mutation event was observed. Using a maximum likelihood method, the mutation rate was indirectly estimated as 2.5 x 10(-5). These results suggest that D10S2325 is a useful marker for forensic casework and paternity analysis.     

AGCU Mini系统在法医学中的应用

目的考察及评价AGCU Mini系统在法医学实践中的应用价值。方法应用AGCU Mini系统检测12 775份陈旧血样,进行梯度DNA模板浓度分析,并与IdentifilerTM试剂盒检测结果进行比对,评价体系的检测成功率及方法的灵敏度。针对AGCU Mini系统中D19S253基因座,对699份浙江汉族无关个体进行多态性调查。结果 12 775份陈旧血样采用AGCU Mini试剂盒检测,12 885份(96.1%)分型成功,检测灵敏度为40pg(10μL体系),方法成功率及灵敏度均高于IdentifilerTM试剂盒。D19S253基因座共检出9个等位基因,频率范围为0.005 7～0.316 2,杂合度为0.814 0,多态性信息含量为0.772 9。结论 AGCU Mini系统可用于法医微量物证的STR分析,与相关试剂盒联合使用价值更高。     

Estimating the Number of Contributors to Forensic DNA Mixtures: Does Maximum Likelihood Perform Better Than Maximum Allele Count?

Abstract: Determining the number of contributors to a forensic DNA mixture using maximum allele count is a common practice in many forensic laboratories. In this paper, we compare this method to a maximum likelihood estimator, previously proposed by Egeland et al., that we extend to the cases of multiallelic loci and population subdivision. We compared both methods’ efficiency for identifying mixtures of two to five individuals in the case of uncertainty about the population allele frequencies and partial profiles. The proportion of correctly resolved mixtures was >90% for both estimators for two‐ and three‐person mixtures, while likelihood maximization yielded success rates 2‐ to 15‐fold higher for four‐ and five‐person mixtures. Comparable results were obtained in the cases of uncertain allele frequencies and partial profiles. Our results support the use of the maximum likelihood estimator to report the number of contributors when dealing with complex DNA mixtures.     

Genetic profiling of a central Venezuelan population using 15 STR markers that may be of forensic importance

The AmpFlSTR Identifiler kit has recently been accepted for use in DNA databasing of forensic samples in the FBI's National DNA Index System. In the present study, we used this kit to analyze the allele distribution of 15 short tandem repeat markers (STR) in individuals living in Caracas city, Venezuela. The allele frequencies of two of these STR, D2S1338 and D19S433, have not previously been reported for this or any other Latin American population. The results indicate that for the population here studied, the 15 STR tested are useful markers for paternity testing and forensic casework.     

Spanish population data on the loci D13S317, D7S820, and D16S539 generated using silver staining (SilverSTR III Multiplex).

A set of 212 samples from unrelated Spanish Caucasians living in Andalucia (southern Spain) were analyzed with a new commercially-available kit for multiplex amplification of 3 STR loci (D13S137, D7S820, and D16S539), manual denaturing polyacrylamide gel electrophoresis and silver staining. These three loci are of special interest for the forensic community since they are a part of the 13 CODIS-core STR loci. The results show that the loci D13S317 and D16S539 meet Hardy-Weinberg expectations (HWE), but the locus D7S820 did not meet HWE (p = 0.003). However, there was no detectable departures from independence (i.e., linkage disequilibrium) between any pair-wise combination of loci. The D7S820 data were further investigated. The excess homozygosity was due to an excess of D7S820 10, 10 homozygotes. To determine if the allele frequency data are meaningful and can be applied to forensic identity cases, the Spanish D7S820 allele frequency data were compared with four other Caucasian sample populations. The D7S820 allele frequencies were statistically similar; thus, the results support that the allele frequency data can be used reliably for estimating DNA profile frequencies.     

Allele and genotype frequencies for the STR locus D18S51 in a western German population

Genetic marker typing based on DNA amplification by the polymerase chain reaction (PCR) increasingly is being employed in forensic casework and for paternity testing. Allele frequencies were determined using PCR for 102 unrelated Germans (Rhine area) for the locus D18S51. Twelve alleles were observed, with frequencies ranging from 0.005 (allele 11) to 0.191 (allele 14). The observed heterozygosity was 0.867, and the power of discrimination was 0.968. There was no deviation from expectations under Hardy-Weinberg assumptions (P = 0.451).     

Study on the application of parent-of-origin specific DNA methylation markers to forensic genetics

In paternity test, especially in motherless cases, the allele inherited from father (obligatory gene, OG) often cannot be determined. The paternity exclusion probability (PE) of a genetic marker is reduced considerably. Therefore, it is necessary to develop a new technique, by which the parental origin of alleles can be determined without genealogical analysis. In this paper, we explored the possibility of using parent-of-origin specific DNA methylation markers to determine the parental origin of alleles, choosing the imprinted single nucleotide polymorphism (SNP) locus rs220028 (A/G) as a model system. We typed the SNP by mutagenically separated PCR (MS-PCR). The frequencies of alleles were A = 0.5085, G = 0.4915; the unbiased heterozygosity was 0.5020. In order to discriminate between the maternal allele and paternal allele, post-digestion MS-PCR, a novel PCR based methylation analysis and SNP typing technique was developed and performed on 18 heterozygous children, and the methylated maternal allele was detected specifically. As a pilot study on the use of epigenetic markers in forensic genetics, our results demonstrated the feasibility of using parent-of-origin specific DNA methylation markers to determine the parental origin of alleles.     

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.     

Analysis of eight polymorphic human genetic markers in a well-defined Greek population

The use of DNA in forensic science has become a basic tool for person identification or parentage testing. The use of polymorphic markers permits the formation of a unique profile for each individual. The knowledge of allele frequencies in a given population allows the scientist to estimate the probability of a particular allele combination. For this task, allele databanks are essential. In this report, the authors estimate the frequencies of eight polymorphic markers (namely, HumFES, HumF13A1, HumTHO1, HumVWA, HumFABP2, HumLIPOL, D1S80, and D17S5) in a randomly selected sample from Crete, Greece. The allele profile of all markers, with the exception of D17S5 and HumFABP2, concurs with previous reports and international data.     

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.     

A multifaceted,multijurisdictional, multiagency,and multidisciplinary approach to investigating unidentified and missing persons cases in Australia

Currently, there are approximately 750 unidentified human remains and 2500 long-term missing persons in Australia. The Australian Federal Police National DNA Program for Unidentified and Missing Persons (Program) is using a multifaceted, multijurisdictional, multiagency, and multidisciplinary approach in a dedicated effort to identify these unknown deceased persons, scientifically link them to known missing persons, and provide answers to their families. The nationally coordinated Program provides its police, forensic, and coronial stakeholders with a suite of contemporary forensic technologies, databases, and experts to forensically examine the skeletonised remains and recover post-mortem data for comparison to the available ante-mortem data for each missing person. Through a number of physical and virtual public outreach activities, families with missing relatives have been encouraged to provide vital ante-mortem forensic information, records, and samples to aid the identification process. To date, this unique Program has assisted to resolve a number of unidentified and missing persons cases from both historical and contemporary contexts, using a combination of genetic and non-genetic techniques, and local and national databases. The centralisation of Program capabilities, expertise, and resources to conduct this type of unique and challenging casework is proving to be the most effective and efficient way to generate investigative leads, identify human remains, and resolve long-term missing persons cases in Australia.     

The STR-based genetic profile of the population from Corsica island (France).

Short tandem repeats (STR) at loci HumFES/FPS, HumVWA, HumCSF1PO, HumTH01, HumFXIIIA01, HumTPOX, HumCD4, D3S1358 are markers of choice for population genetics and validated systems for forensic use. In this report, we analysed their allele frequency distribution in a sample of native blood donors from the two departments of Corsica island (France). Deviations from the Hardy-Weinberg rule and heterozygosity values consistently suggested a spatial differentiation of allele and genotype frequencies across the island. Pairwise comparisons showed that Corsican gene pool presents a high level of heterogeneity between departments and substantially differs from that of neighbouring and historically-related populations. The results suggest the use of local databases to calculate a priori statistics in human identity testing.     

Developmental validation of reduced-size STR Miniplex primer sets

This paper describes a developmental validation study of three Miniplex sets covering 12 of the 13 CODIS loci. As these new sets will be used for the analysis of degraded and low level DNA, the validation studies were performed using 100-125 pg of DNA, the lowest input level at which peak balance, peak intensity, and allele consistency were stable. To demonstrate the applicability of the Miniplex sets to forensic casework, these validation studies were completed in accordance with the Scientific Working Group on DNA Analysis Methods (SWGDAM). A range of tests were performed including studies of concordance with standard multiplex kits, sensitivity and reproducibility, and PCR amplification conditions. Additionally, studies of mixtures, nonhuman and environmentally degraded DNA, and simulated forensic samples were performed. Our results demonstrate that Miniplex STR amplification procedures are a robust and sensitive tool for the analysis of degraded DNA.