Identification Of Missing Persons Research Articles

Pairwise Kinship Analysis by the Index of Chromosome Sharing Using High-Density Single Nucleotide Polymorphisms.

We developed a new approach for pairwise kinship analysis in forensic genetics based on chromosomal sharing between two individuals. Here, we defined “index of chromosome sharing” (ICS) calculated using 174,254 single nucleotide polymorphism (SNP) loci typed by SNP microarray and genetic length of the shared segments from the genotypes of two individuals. To investigate the expected ICS distributions from first- to fifth-degree relatives and unrelated pairs, we used computationally generated genotypes to consider the effect of linkage disequilibrium and recombination. The distributions were used for probabilistic evaluation of the pairwise kinship analysis, such as likelihood ratio (LR) or posterior probability, without allele frequencies and haplotype frequencies. Using our method, all actual sample pairs from volunteers showed significantly high LR values (i.e., ≥ 108); therefore, we can distinguish distant relationships (up to the fifth-degree) from unrelated pairs based on LR. Moreover, we can determine accurate degrees of kinship in up to third-degree relationships with a probability of > 80% using the criterion of posterior probability ≥ 0.90, even if the kinship of the pair is totally unpredictable. This approach greatly improves pairwise kinship analysis of distant relationships, specifically in cases involving identification of disaster victims or missing persons.

GHEP-ISFG collaborative simulated exercise for DVI/MPI: Lessons learned about large-scale profile database comparisons

The GHEP-ISFG Working Group has recognized the importance of assisting DNA laboratories to gain expertise in handling DVI or missing persons identification (MPI) projects which involve the need for large-scale genetic profile comparisons. Eleven laboratories participated in a DNA matching exercise to identify victims from a hypothetical conflict with 193 missing persons. The post mortem database was comprised of 87 skeletal remain profiles from a secondary mass grave displaying a minimal number of 58 individuals with evidence of commingling. The reference database was represented by 286 family reference profiles with diverse pedigrees. The goal of the exercise was to correctly discover re-associations and family matches. The results of direct matching for commingled remains re-associations were correct and fully concordant among all laboratories. However, the kinship analysis for missing persons identifications showed variable results among the participants. There was a group of laboratories with correct, concordant results but nearly half of the others showed discrepant results exhibiting likelihood ratio differences of several degrees of magnitude in some cases. Three main errors were detected: (a) some laboratories did not use the complete reference family genetic data to report the match with the remains, (b) the identity and/or non-identity hypotheses were sometimes wrongly expressed in the likelihood ratio calculations, and (c) many laboratories did not properly evaluate the prior odds for the event. The results suggest that large-scale profile comparisons for DVI or MPI is a challenge for forensic genetics laboratories and the statistical treatment of DNA matching and the Bayesian framework should be better standardized among laboratories.

X-STRs as a tool for missing persons identification using only siblings as reference

Although the most suitable people for the identification of missing persons are the parents and/or children of the disappeared, often these relatives are not available, the only alternative being the siblings. Research of biological relations between siblings and half siblings is commonly based on the use of autosomal markers; however, in some cases, the legally stipulated probability of likelihood ratio (LR) (≥0.9999) cannot be reached. This is the main reason, why it is important to consider the use of other markers such as those linked to the sex chromosomes (X and Y). In this study, we focused on the usefulness of X chromosome STRs for the establishment of relationships between siblings, we propose the implementation of them routinely in the identification of missing persons, a case type which in Colombia has increased due to the last decades of armed conflict.

Genetic identification of burned corpses as a part of disaster victim identification effort

Forensic genetics is extremely useful for the resolution of criminal cases, identification of missing persons and paternity/kinship testing. The Italian town of Prato, near Florence, has been a centre of Italian textile industry since the 12th century and now it hosts a number of Chinese-run textile factories producing garments for export across Europe. In December 2013 a fire burned a factory where eleven Chinese workers were employed. The fire was due to a short circuit and it surprises the workers in the makeshift dormitory. After the fire was extinguished, remains of seven people were found by rescuers.The identification was carried out in accordance with Interpol protocols (AM and PM form) and in every case one of the three primer identifiers was satisfied. Relatives of the victims were available for information and biological samples’ collection.Here, we show the protocol adopted in the forensic genetics laboratory that included the use of a wide battery of markers STRs, Y-STR and biostatistics evaluation of different assumptions about the identification of these persons.

Algorithm aligen: Simple method of encryption and matching with genetic profiles in a system of STR identification database

During the DNA identification process of 15000 missing persons in Peru between 1980 and 2000, we observed many cases of random matches due to the population genetic structure (founder effect, low gene flow between communities and inbreeding). In this genetic context, since 2002, we have been developing an algorithm named ALIGEN with the aim of improving the match and identification. This algorithm performs a meiosis simulation in two DNA databases (relatives and missing persons). In each DNA database ALIGEN generated the haploid profiles (hap-file) for each genetic profile divided in five groups of four STR markers (match group) with a total of twenty STR markers. Simultaneously, we performs a kinship analysis using the model of allele Identity by descendent (IBD) using a threshold of 90% posterior probability in the case of fullsibs with the aim to obtain only the significative relationship and avoiding the random matches. To support the first analysis, the algorithm generated a genetic distances between two genetic profile using hap-file and this form the matrix of likeness that correspond to the genetic distance among all genetic profiles (relatives and missing persons). This matrix is used in MEGA with the aim to obtain a relationship tree. In this way we can confirm the matches, the random matches and evidence of unknown relationships. Other characteristic of the algorithm, it can able to ensure the DNA information privacy through the encryption of each genetic profile using a Hash encryption model with de hap-file generated and it is a criteria very important in the future of populations DNA databasing. Finally, ALIGEN have been validated in the last 13 years solving the identification of missing persons in many cases at national and international level. For this raison, we wish share this algorithm as an easy tool that it can be implementing for any laboratory using the formulas described in this article.

Assay Development and Validation of an 8-SNP Multiplex Test to Predict Eye and Skin Coloration.

Identifying human remains is one of the many responsibilities of forensic scientists. An eye- and skin-color predictor translates genotypic information into phenotypic description. Eight single nucleotide polymorphisms (SNPs) are utilized for this predictor, five for eye, and six for skin coloration. Here, we describe the development and validation of an 8-SNP multiplex assay that consists of a multiplex PCR, followed by a multiplexed single-base primer extension reaction generating fluorescently labeled oligonucleotides of distinct length that are detected by multicolor capillary electrophoresis. Validation of this assay included tests for reproducibility, reliability, sensitivity, species specificity, its performance on degraded DNA, and on forensic samples. It can be concluded that the 8-SNP multiplex assay is robust and can be used on challenging samples, including bones, to reliably determine the genotypes to predict eye and skin color of individuals. This information can assist in the identification of human remains and missing persons.

Reconstrucción osteobiográfica en odontología forense

En las Ciencias Forenses la estimación de la Reconstrucción Osteobiográfica de un sujeto forma parte importante del complejo proceso de identificación humana. En la Reconstrucción Osteobiográfica toma en cuenta los métodos para la estimación de la edad, el sexo, los ancestros y la estatura basados principalmente en el estudio del macizo cráneofacial, su morfología, dimensiones métricas apoyan a las ciencias forenses con una importante batería de datos que contribuyen a la individualización de personas desaparecidas. En este sentido, la carta dental que se aplica regularmente en la identificación es una mínima parte de toda la información que podemos obtener del sistema dental. Aquí podemos decir, al igual que para los huesos, el macizo cráneofacial y dentro de ello los dientes hablan y cuentan la historia de la persona desaparecida que en vida formó parte de un medio ambiente, un grupo social determinado y de una individualidad que lo hace único e irrepetible.

Models and implementation for relationship problems with dropout.

Allelic dropout in relationship problems may commonly appear in areas such as disaster victim identification and the identification of missing persons. If dropout is not accounted for, the results may be incorrect interpretation of profiles, loss of valuable information and biased results. In this paper, we explore different models for dropout in kinship cases and present an efficient implementation for one of the models. The implementation allows for dropout to be handled simultaneously with phenomena like silent alleles and mutations that may also cause discordances in relationship data, in addition to subpopulation correction. The implemented dropout model is freely available in the new version of the Familias software. The concepts and methods are illustrated on real and simulated data.

DNA Analysis for Missing Person Identification in Mass FatalitiesA. C. Sozer

DNA Analysis for Missing Person Identification in Mass FatalitiesA. C. Sozer

Establishment of an ISO 17025:2005 accredited forensic genetics laboratory in Italy

Forensic genetics is extremely useful for the resolution of criminal cases, identification of missing persons and in paternity/kinship testing. Each and every laboratory that works in the forensic genetics area has developed its own working method independently, however, generally in accordance with international guidelines. More than thirty institutional, public and private forensic laboratories that deal with the identification/paternity testing through DNA in Italy have been surveyed, but to this day, only five public laboratories (four of the police and one of a university hospital) and two private ones are accredited. There are, however, many other laboratories that perform occasional forensic genetics activities that have not been surveyed. The need to achieve the ISO 17025:2005 accreditation may represent for these laboratories an excellent opportunity to improve their activities. Although the DNA analysis for forensic investigation is used in Italy since the beginning of the technique, the quality of the results has been called into question more than once, as it appears by many court cases in which the results of genetic tests have been subject to strong criticisms. Obviously, the ISO 17025:2005 is not sufficient to guarantee the quality of the results. It is essential to show the laboratory working method to the scientific community in order to obtain reliable and robust analytical results that can be used in court to accuse/exonerate individuals accused of a crime or to assign a true biological father to a child. Here, we show a part of the workflow validation process of the internal method used in the Forensic Genetic Service (FGS) of the Diagnostic Genetics Unit (DG) of the Careggi University Hospital. This article outlines some relevant aspects of the methods adopted to ensure robustness, reliability and reproducibility of genetic profiles used for forensic identification.

Missing person identification and positioning system by means of wireless communication network

Missing person identification and positioning system by means of wireless communication network

Future directions of forensic DNA databases.

Forensic DNA databases are indispensable tools of the law enforcement system. The purpose of establishing forensic DNA databases was to develop investigative leads for solving crime and usually was the purview of “criminal justice agencies for law enforcement identification purposes” (1). The forensic DNA databases of most countries generally contain two types of profiles: 1) reference profiles from convicted offenders and/or arrestee profiles; these profiles are from known sources; and 2) forensic profiles which derive from crime scenes and are characteristically from unknown sources. In a typical database search, an unknown forensic profile is searched against the convicted offender and arrestee profiles (or can be searched against other unknown forensic profiles) to determine if an association, often called a match or hit, can be found. The hit can be used to develop investigation leads. As of May 2013, China and the United States (US) maintain the two largest forensic DNA databases, containing more than 20 and 12 million profiles and have produced over 410 000 (2) and 185 000 hits (3), respectively. In addition to direct matching between known and unknown sample profiles, profiles from missing persons and their relatives, as well as unidentified human remains, are included in a number of databases (2,3). Missing person identification also is an invaluable module for investigating certain crimes. For example, as of June 2013, China has successfully identified and rescued 2455 trafficked children through the use of its DNA database (2). The US National Missing and Unidentified Persons System (NamUs), which uses other meta-data has successfully solved 3499 missing persons cases as of August 2012 (4). As expected with the great success of the use of forensic DNA databases, new challenges are emerging. The databases are experiencing rapid growth, and thus there is a potential of increased adventitious hits; the power for current and new applications (eg, missing person identification and familial searching) require additional infrastructure support; and there is an increased desire for international data sharing (5-7), which possibly could be hampered if only a relatively small number of loci is shared among laboratories worldwide.

Sexual and Ethnic Differences in Facial Anthropometry of Northwest Indians

ABSTRACT Aim To determine sexual, age related and ethnic differences in somatometric measurements of northwest Indian (NWI) and to elucidate relation between these measurements. Context This information will help surgeons during the planning stages of facial plastic surgery and forensic experts in reconstructing face for identification of homicide victims and missing persons. Materials and methods The study included 15 somatometric measurements on 173 males and 127 females healthy subjects from 18 to 70 years. Results Statistically significant sexual differences were observed in parameters of head, face, nose and biocular breadth and interpupillary distance. No consistent age related patterns were found except in eye and nasal regions in males. The relation between different parameters showed almost equal length and breadth of face. In majority of subjects, bigonial breadth was smaller than minimum frontal breadth but larger than face breadth. Interocular breadth was smaller than ocular and nasal breadth while nasal height and length were larger than lower face height. Ethnic comparisons render smaller values in most of the parameters. How to cite this article Sahni D, Sanjeev, Harjeet, Jaggi S, Aggarwal A. Sexual and Ethnic Differences in Facial Anthropometry of Northwest Indians. J Postgrad Med Edu Res 2014; 48(4):171-182.

Development of a novel forensic STR multiplex for ancestry analysis and extended identity testing

There is growing interest in developing additional DNA typing techniques to provide better investigative leads in forensic analysis. These include inference of genetic ancestry and prediction of common physical characteristics of DNA donors. To date, forensic ancestry analysis has centered on population-divergent SNPs but these binary loci cannot reliably detect DNA mixtures, common in forensic samples. Furthermore, STR genotypes, forming the principal DNA profiling system, are not routinely combined with forensic SNPs to strengthen frequency data available for ancestry inference. We report development of a 12-STR multiplex composed of ancestry informative marker STRs (AIM-STRs) selected from 434 tetranucleotide repeat loci. We adapted our online Bayesian classifier for AIM-SNPs: Snipper, to handle multiallele STR data using frequency-based training sets. We assessed the ability of the 12-plex AIM-STRs to differentiate CEPH Human Genome Diversity Panel populations, plus their informativeness combined with established forensic STRs and AIM-SNPs. We found combining STRs and SNPs improves the success rate of ancestry assignments while providing a reliable mixture detection system lacking from SNP analysis alone. As the 12 STRs generally show a broad range of alleles in all populations, they provide highly informative supplementary STRs for extended relationship testing and identification of missing persons with incomplete reference pedigrees. Lastly, mixed marker approaches (combining STRs with binary loci) for simple ancestry inference tests beyond forensic analysis bring advantages and we discuss the genotyping options available.

Checking of position of face organs with anatomical structures of skull in frontal position, important regarding superposition (experimental work on the topogram of author's head)

For proper execution of superposition as a method in face identification of missing persons, it is necessary to have an accurate insight into the correlation between face organs and skull. The works of many scientists (anatomists, anthropologists) and artists (painters and sculptors) made the canons of proportion of face and body. The work presents checking the position of face organs with anatomic structures of skull on topogram in frontal position. It represents the first experimental work of this kind in our country. Topographic-anatomic images of the head of author himself were used. Images were made on August, 25. 2006. using MS (Multislice) CT unit at the Institute for Radiology, Clinical Center of Vojvodina, Novi Sad. A total of 33 of head images in frontal position were selected. Recordings show the gradual ''removal'' of the skin, muscles and blood vessels of the head in order to display the projection of face organs to anatomical structures of the skull. It can be clearly observed the central position of the eyeball lenses in orbital cavities, eyelids annexes, nostrils width and position of the tip of the nose in relation to the edges of the piriform aperture of skull. Correlation of facial soft tissue anthropometric points and skull anthropometric points is clearly observed in the frontal position of the head.

Identification of Organic Traces in Pre-Trial and Judicial Investigations, using DNA Fragment Analysis

ABSTRACTThis study is based on the presentation and analysis of survey results from expert reports and investigations carried out for 12 years in the DNA analysis laboratory in the Department of Forensic Medicine and Deontology at the Medical Faculty of the Medical University of Sofia. Using the method of DNA profiling and, in particular, the practical application of DNA fragment analysis in forensic practice, we conducted successful profiling of biological traces on material evidence and identification of the individual, which led to a significant increase in the percentage of detected crimes and DNA identification of missing persons by their biological traces. The success of the expert cases closed by us is based on the population studies conducted in the laboratory, as the primary basis for deriving accurate mathematical solutions consistent with the international practice. The experimental models used in our research allowed us to apply some modified extraction, polymerization and electrophoretic procedures with individual assessment and approach to solving complex genetic problems.

Response to: Use of prior odds for missing persons identifications - authors' reply

Please see related article: http://www.investigativegenetics.com/content/3/1/2

Reply to Budowle, Ge, Chakraborty and Gill-King: use of prior odds for missing persons identifications

Prior probabilities represent a core element of the Bayesian probabilistic approach to relatedness testing. This letter opinions on the commentary Use of prior odds for missing persons identifications by Budowle et al., published recently in this journal. Contrary to Budowle et al., we argue that the concept of prior probabilities (i) is not endowed with the notion of objectivity, (ii) is not a case for computation, and (iii) does not require new guidelines edited by the forensic DNA community--as long as probability is properly considered as an expression of personal belief.

Assessing the potential of next generation sequencing technologies for missing persons identification efforts

To assess the utility of next generation sequencing (NGS) technologies for missing persons applications, we have recently initiated a study of various platforms and target enrichment strategies for sample types regularly encountered in our large-scale identification efforts. Specific laboratory workflows based on target marker enrichment and NGS platform are being considered for different sample types, and the overall effort is being undertaken with a strong emphasis on both raw data and final consensus sequence quality. The current study is first and foremost a general evaluation of these data and technologies from the standpoint of forensic application, yet the strategy we are pursuing is ultimately intended to facilitate NGS integration into standard casework laboratories. We are, therefore, evaluating NGS workflows and data for the typical nuclear and mitochondrial DNA markers used in forensics, while still allowing for future work that may take greater advantage of the strengths of these technologies. Here, we present an overview of our NGS strategy.

Development of a SNP multiplex assay for the inference of biogeographical ancestry and pigmentation phenotype

SNPs exhibiting strong associations with specific populations and/or pigmentation phenotypes have been identified in mitochondrial, Y chromosome and autosomal DNA. Ancestry and phenotype inferences gained from DNA may assist forensic investigations of unknown perpetrators or aid identification of missing persons and disaster victims. To test the predictive power of combining SNPs from all three DNA types, 21 coding region mitochondrial SNPs, 28 Y chromosome SNPs and 14 autosomal SNPs were selected and analysed in a hierarchical multiplex assay.