Age Estimation Based on DNA Methylation and Its Application Prospects in Forensic Medicine / 法医学杂志

With the improvement of DNA methylation detection techniques, studies on age-related methylation sites have found more age-specific ones across tissues, which improves the sensitivity and accuracy of age estimation. In addition, the establishment of various statistical models also provides a new direction for the age estimation of tissues from different sources. This review summarizes the related studies of age estimation based on DNA methylation from the aspects of detection technology, age-related cytosine phosphate guanine site and model selection in recent years.

Research Progress on Molecular Biology of Human Height Estimation / 法医学杂志

As an important anthropometric characteristic, human height not only contributes to the recognition of other anthropological characteristics and genetic risk factors, but also is an important part of forensic DNA phenotyping studies. Accurate estimation of height can provide more complete information about the phenotype of suspects and provide help to solve cases. In recent years, having benefited from the rapid development of molecular biological techniques and bioinformatics, height-related genetics research has made some progress. This paper describes the research progress of human height estimation from the genetic variation and the epigenetic inheritance perspectives and looks into the future research direction.

Application of SNaPshot Technology in Semen-Specific cSNP Genetic Marker / 法医学杂志

OBJECTIVES@#To explore the feasibility of genetic marker detection of semen-specific coding region single nucleotide polymorphism (cSNP) based on SNaPshot technology in semen stains and mixed body fluid identification.@*METHODS@#Genomic DNA (gDNA) and total RNA were extracted from 16 semen stains and 11 mixtures composed of semen and venous blood, and the total RNA was reverse transcribed into complementary DNA (cDNA). The cSNP genetic markers were screened on the validated semen-specific mRNA coding genes. The cSNP multiplex detection system based on SNaPshot technology was established, and samples were genotyped by capillary electrophoresis (CE).@*RESULTS@#A multiplex detection system containing 5 semen-specific cSNPs was successfully established. In 16 semen samples, except the cSNP located in the TGM4 gene showed allele loss in cDNA detection results, the gDNA and cDNA typing results of other cSNPs were highly consistent. When detecting semen-venous blood mixtures, the results of cSNP typing detected were consistent with the genotype of semen donor and were not interfered by the genotype of venous blood donor.@*CONCLUSIONS@#The method of semen-specific cSNPs detection by SNaPshot technology method can be applied to the genotyping of semen (stains) and provide information for determining the origin of semen in mixed body fluids (stains).

Construction of an Analysis Model of mRNA Markers in Menstrual Blood Based on Naïve Bayes and Multivariate Logistic Regression Methods / 法医学杂志

OBJECTIVES@#To establish the menstrual blood identification model based on Naïve Bayes and multivariate logistic regression methods by using specific mRNA markers in menstrual blood detection technology combined with statistical methods, and to quantitatively distinguish menstrual blood from other body fluids.@*METHODS@#Body fluids including 86 menstrual blood, 48 peripheral blood, 48 vaginal secretions, 24 semen and 24 saliva samples were collected. RNA of the samples was extracted and cDNA was obtained by reverse transcription. Five menstrual blood-specific markers including members of the matrix metalloproteinase (MMP) family MMP3, MMP7, MMP11, progestogens associated endometrial protein (PAEP) and stanniocalcin-1 (STC1) were amplified and analyzed by electrophoresis. The results were analyzed by Naïve Bayes and multivariate logistic regression.@*RESULTS@#The accuracy of the classification model constructed was 88.37% by Naïve Bayes and 91.86% by multivariate logistic regression. In non-menstrual blood samples, the distinguishing accuracy of peripheral blood, saliva and semen was generally higher than 90%, while the distinguishing accuracy of vaginal secretions was lower, which were 16.67% and 33.33%, respectively.@*CONCLUSIONS@#The mRNA detection technology combined with statistical methods can be used to establish a classification and discrimination model for menstrual blood, which can distignuish the menstrual blood and other body fluids, and quantitative description of analysis results, which has a certain application value in body fluid stain identification.

Cross-Platform Application of DNA Methylation Age Estimation Model in Eastern Chinese Han Population / 法医学杂志

OBJECTIVES@#To evaluate the forensic application value of an age estimation model based on DNA methylation in eastern Chinese Han population, and to provide a theoretical basis for exploring age estimation models suitable for different detection platforms.@*METHODS@#According to the 6 age-related methylation sites in the published blood DNA methylation age estimation models of Chinese Han population, the DNA methylation level of 48 samples was detected by pyrosequencing and next-generation sequencing (NGS). After submitting DNA methylation levels to the age estimation model, the DNA methylation ages were predicted and compared with their real ages.@*RESULTS@#The 6 DNA methylation sites in both detection techniques were age-related, with an R2 of 0.85 and a median absolute deviation (MAD) of 4.81 years when using pyrosequencing；with an R2 of 0.84 and MAD of 4.41 years when using NGS.@*CONCLUSIONS@#The blood DNA methylation age estimation model can be used under pyrosequencing and multi-purpose regional methylation enrichment sequencing technology based on NGS and it can accurately estimate the age.

Methods and Research Hotspots of Forensic Kinship Testing / 法医学杂志

Kinship testing is widely needed in forensic science practice. This paper reviews the definitions of common concepts, and summarizes the basic principles, advantages and disadvantages, and application scope of kinship analysis methods, including identity by state (IBS) method, likelihood ratio (LR) method, method of moment (MoM), and identity by descent (IBD) segment method. This paper also discusses the research hotspots of challenging kinship testing, complex kinship testing, forensic genetic genealogy analysis, and non-human biological samples.

Genetic diversity analysis of forty-three insertion/deletion loci for forensic individual identification in Han Chinese from Beijing based on a novel panel / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Due to the virtues of no stutter peaks, low rates of mutation, and short amplicon sizes, insertion/deletion (InDel) polymorphism is an indispensable tool for analyzing degraded DNA samples from crime scenes for human identifications (Wang et al., 2021). Herein, a self-developed panel of 43 InDel loci constructed previously by our group was utilized to evaluate the genetic diversities and explore the genetic background of the Han Chinese from Beijing (HCB) including 301 random healthy individuals. The lengths of amplicons at 43 InDel loci in this panel ranged from 87 to 199 bp, which indicated that the panel could be used as an effective tool to utilize highly degraded DNA samples for human identity testing. The loci in this panel were validated and performed well for forensic degraded DNA samples (Jin et al., 2021). The combined discrimination power (PD) and combined probability of exclusion (PE) values in this panel indicated that the 43 InDel loci could be used as the candidate markers in personal identification and parentage testing of HCB. In addition, population genetic relationships between the HCB and 26 reference populations from five continents based on 19 overlapped InDel loci were displayed by constructing a phylogenetic tree, principal component analysis (PCA), and population genetic structure analysis. The results illustrated that the HCB had closer genetic relationships with the Han populations from Chinese different regions.

Application Progress of Massively Parallel Sequencing Technology in STR Genetic Marker Detection / 法医学杂志

In recent years, more and more forensic genetics laboratories have begun to apply massively parallel sequencing (MPS) technology, that is, next-generation sequencing (NGS) technology, to detect common forensic genetic markers, including short tandem repeat (STR), single nucleotide polymorphism (SNP), the control region or whole genome of mitochondrial DNA (mtDNA), as well as messenger RNA (mRNA), etc., for forensic practice, such as individual identification, kinship analysis, ancestry inference and body fluid identification. As the most widely used genetic marker in forensic genetics, STR is currently mainly detected by capillary electrophoresis (CE) platform. Compared with CE platform, MPS technology has the advantages of simultaneous detection of a large number of genetic markers, massively parallel detection of samples, the polymorphism of sequence detected by NGS makes STR have the advantages of higher resolution and system efficiency. However, MPS technology is expensive, there is no uniform standard so far, and there are problems such as how to integrate MPS-STR data with the existing CE-STR database. This review summarizes the current status of the application of MPS technology in the detection of STR genetic markers in forensic genetics, puts forward the main problems that need to be solved urgently, and prospects the application prospect of this technology in forensic genetics.

Parámetros forenses de diez microsatélites del cromosoma X en una muestra de la población del Estado Zulia, Venezuela / Forensic parameters of ten X chromosome microsatellites polymorphisms in a sample of the Zulia State population, Venezuela

Justificación:Las repeticiones cortas en tándem (STRs) están distribuidos por toda la extensión del genoma humano, los ubicados en los cromosomas autosómicos y en el cromosoma Y han sido ampliamente utilizados en los laboratorios de genética forense debido a las características y patrones hereditarios que estos poseen. ObjetivoA fin de caracterizar y determinar parámetros de interés forense en secuencias de tipo STR del cromosoma X (DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08 y DXS7423) en la población del Estado Zulia.Metodología:Se eligieron 108 individuos (130 cromosomas X),cuyos ADN se amplificaron mediante la reacción en cadena de la polimerasa, los fragmentos se separaron por electroforesis capilar y los alelos reportadoscon respecto a la escalera alélica. Resultados: El contenido de información polimórfica demostró ser mayor de 0,5 en todos los microsatélites y el poder de discriminación acumulado fue de 0,99999997 en mujeres y 0,99999816 en hombres.Conclusiones:Los datos demuestran que los microsatélites del cromosoma X analizados son lo suficientemente informativos como para ser utilizados en casos de vínculos biológicos complejos y la identificación humana...(AU)

Frecuencia de heteroplasmia en las regiones hipervariables HVI y HVII del ADN Mitocondrial en una muestra de la población de Maracaibo, Venezuela / Frequency of heteroplasmy in HVI and HVII mitocondrial genome regions in a population sample of Maracaibo,Venezuela

Justificación:El estudio de los polimorfismos de las regiones hipervariables I y II (HVI y HVII) del ADN mitocondrial (ADNmt) se ha convertido en una herramienta invaluable para la ciencia forense, ya que enalgunas ocasionesun determinadoindividuopuedepresentar más de un tipo de ADNmitocondrial,este fenómeno es conocido como Heteroplasmia. Lacoexistencia de dos o más poblaciones de ADNmt puedeocurrir enuna sola mitocondria, célula oindividuo, lo que puede aumentar la complejidad en la interpretación de los resultados de las experticias forenses. Objetivos:Analizar la frecuencia de la heteroplasmia en las regiones HVI y HVII del genoma mitocondrialen una muestra de la población de Maracaibo. Metodología:Seseleccionaron al azar 50 muestras de ADN de la población de Maracaibo, las regiones hipervariables se amplificaron mediantereacción en cadena de la polimerasa, posteriormente se secuenciaron mediante método de Sanger y los fragmentos se separaron por electroforesis capilar, se reportaron las diferencias con respecto a la secuencia de referencia de Cambridge. Resultados: El 26% de las muestras presentaron heteroplasmia en la región HVI, el 52%en la región HVII.Conclusiones:El hecho deaparecer laheteroplas-miaen una determinadasecuencianoinválida el uso del análisis del ADN mitocondrial con fines forenses, dependiendo de la complejidad del caso a peritar,la heteroplasmia puede ser de gran ayuda...(AU)

Ancestry Inference Using the ForenSeqTM DNA Signature Prep Kit / 法医学杂志

Objective To evaluate the effect of 56 ancestry informative single nucleotide polymorphism （aiSNP） genetic markers in the ForenSeqTM DNA Signature Prep Kit on ancestry inference. Methods A total of 85 samples from five populations including Hebei Han population, Inner Mongolia autonomous region Mongolian population, Tibet autonomous region Tibetan population, Xinjiang Uygur autonomous region Uygur population and Nigerian population were collected. The library was constructed with the ForenSeqTM DNA Signature Prep Kit and sequencing was performed based on the MiSeq FGx Forensic Genomics System. Using universal analysis software （UAS） of ForenSeqTM, principal component analysis （PCA）, Structure and likelihood ratio method was used on the genotyping data of 56 aiSNP markers, respectively, and the genetic relationships between populations and inference of the origin of ancestors were analyzed. Results Among the five populations tested, the four ethnic populations in China （Hebei Han population, Inner Mongolia autonomous region Mongolian population, Tibet autonomous region Tibetan population and Xinjiang Uygur autonomous region Uygur population） could be significantly distinguished from Nigerian population. Xinjiang Uygur autonomous region Uygur individuals were shown as having mixed origins of ancestors and could be distinguished from the other three Chinese populations. However, the other three populations in China （Hebei Han population, Inner Mongolia autonomous region Mongolian population and Tibet autonomous region Tibetan population） could not be effectively distinguished by the system. Conclusion The 56 aiSNP markers in the ForenSeqTM DNA Signature Prep Kit can make accurate ancestry inference from the intercontinental level, but it is not yet able to distinguish between Chinese subpopulations.

Pigmentation Phenotype Prediction of Chinese Populations from Different Language Families / 法医学杂志

Objective To predict the pigmentation phenotypes of Chinese populations from different language families, analyze the differences and provide reference data for forensic anthropology and genetics. Methods The HIrisPlex-S multiplex amplification system with 41 loci related to pigmentation phenotypes was constructed in the laboratory, and 2 666 DNA samples of adult males of 17 populations from six language families, including Indo-European, Sino-Tibetan, Altaic, Hmong-Mien, Tai-Kadai and Austro-Asiatic language families distributed in different regions of China were genotyped. The pigmentation phenotype category of each individual was predicted using the online prediction system （https://HIrisPlex.erasmusmc.nl/）, and then the output data were statistically analyzed. Results About 1.92% of the individuals of Asian-European admixed populations from Indo-European and Altaic language families had blue eyes and 34.29% had brown or gold hair. The phenotypes of the color of eyes and hair of other populations had no significant difference, all individuals had brown eyes and black hair. There were differences in skin color of populations of different language families and geographical areas. The Indo-European language family had the lightest skin color, and the Austro-Asiatic language family had the darkest skin color; the southwestern minority populations had a darker skin color than populations in the plain areas. Conclusion The prediction results of pigmentation phenotype of Chinese populations are consistent with the perception of the appearance of each population, proving the reliability of the system. The color of eyes and hair are mainly related to ancestral components, while the skin color shows the differences between language families, and is closely related to geographical distribution of populations.

Research Progress on Age Estimation Based on DNA Methylation / 法医学杂志

Age estimation is of great significance in the fields of criminal investigation and forensic identification. It can provide the age information of individuals to judicial departments to facilitate the development of judicial work. In recent years, age estimation methods expanded from the morphological level to the molecular biology level. With the rapid development of epigenetics represented by DNA methylation, and the advancement of DNA methylation detection technology together with the detection platform, many age estimation methods based on DNA methylation biomarkers, or using several biological fluids, such as blood, blood stains, saliva, semen stains, etc. are developed. Currently, researches related to age estimation based on DNA methylation are relatively widely carried out. This paper summarizes the researches on age estimation based on DNA methylation, in order to provide references for related studies and forensic applications.

Research Progress on Forensic Genetics of Facial Morphological Depiction / 法医学杂志

Forensic DNA phenotyping （FDP） analysis uses DNA from biological samples left in crime scenes to predict individual phenotypic traits, such as geographical origin of ethnic group, height, weight, skin color, hair color and shape, iris color, male baldness, facial morphology, age, etc., thereby providing clues for case investigations. Among these traits, features of facial morphology are relatively more complicated. This paper makes an overall analysis of the measurement and collection of facial morphology, research on facial morphology related genes, forensic application and establishment of facial morphology depiction model, ethical issues, etc., then summarizes the latest research progress on features of facial morphology.

From the "Out of Africa Theory" Study to the Application of "DNA Biogeographic Ancestry Inference" in Criminal Investigation / 法医学杂志

Genetic markers, such as single nucleotide polymorphism （SNP）, insertion/deletion （InDel）, were discovered and widely used with the development of whole genome sequencing and bioinformatics technology. The origin and genetic structure of the modern population had been gradually revealed from the perspective of genetics. The study on biogeographic ancestry inference in the field of forensic genetics emerged and developed rapidly, providing clues and scientific basis for the determination of investigation direction and for the narrow of the scope of investigation in the process of case investigation. This paper briefly reviews the research progress, inference methods and development trends of DNA ancestry inference technology.

Application of Touch DNA in Investigation Practice / 法医学杂志

With the continuous development of DNA extraction and testing technology, the DNA left at a crime scene plays a decisive role in the determination of criminal suspects in criminal investigation. But in the meanwhile, the anti-reconnaissance awareness of suspect is growing, which leads to a decrease of evidence left at scene during and after a crime. Therefore, in the process of evidence collection at scene, the finding and extraction of touch biological evidence, and the DNA detection are more and more important. At present, the proportion of touch evidence at the crime scene increases, which plays an increasingly important role in the detection of cases. However, with the characteristics of minute quantities, small size and secrecy, these touch evidence is difficult to be observed. What's more, various forms of pollution at the scene greatly accelerate the degradation rate of trace material, thus, the test and analysis of such material has become the emphasis and difficulty of the forensic evidence identification. This article reviews different kinds, collection and extraction methods of touch DNA, the factors that affect the detection and the problems may meet in the detection for providing an application prospect to the forensic practice.

Genetic Parameters of SNP Loci in Next Generation Sequencing Kits and Their Comparison / 法医学杂志

OBJECTIVES@#To calculate genetic parameters of SNP loci in next generation sequencing kits, and to compare them with STR loci for establishing the conversion ratio between SNP and STR system effectiveness.@*METHODS@#Hardy-Weinberg equilibrium tests were performed in 101 SNP loci of next generation sequencing kits （ForenSeq™ DNA Signature Prep kit and Precision ID Identity Panel kit）. The parameters of system effectiveness of SNP loci in the cases of personal identification, trios, duos, and alleged parents were calculated, which were compared with the genetic parameters of STR loci.@*RESULTS@#Except 2 loci without the data of genotype frequency, other 99 SNP loci conformed to Hardy-Weinberg equilibrium tests （P>0.05）. In ForenSeq™ DNA Signature Prep kit, the CDP of 94 SNP loci was 1-1.152 1×10⁻³⁴, CPEtrio was 1-4.416 9×10⁻⁸, CPEduo was 1-8.483 7×10⁻⁵, and CPEAP was 1-1.222 7×10⁻¹². In Precision ID Identity kit, the CDP was 1-2.052 4×10⁻³³, CPEtrio was 1-8.709 3×10⁻⁸, CPEduo was 1-1.163 8×10⁻⁴, and CPEAP was 1-3.725 7×10⁻¹². In the cases of personal identification, trios, duos and alleged parents, the system effectiveness of 2.85, 4.51, 4.88 and 4.55 SNP loci was equal to that of 1 STR locus, respectively.@*CONCLUSIONS@#With high system effectiveness of SNP loci, the next generation sequencing kits is suitable for personal identification and paternity testing in forensic science.

Aportes de la odontología legal en la identificación humana: revisión de la literatura / Contributions of forensic dentistry to human identification: a reeview of the literature

El presente trabajo trata acerca de aspectos inherentes a la odontología legal, a fin de difundir la importancia del perito odontólogo en la identificación humana mediante el análisis de estructuras anatómicas del sistema estomatognático. Los dientes –que presentan una elevada resistencia a los agentes externos– son empleados a veces por las víctimas como unarma de defensa ante sus atacantes, o por estos últimos para dominar a las primeras. Dado que los dientes alojan el ADN en su interior, las huellas de mordeduras representan evidencias físicas que pueden permitir identificar a los involucrados en un suceso delictivo. Se mencionan programas informáticos para facilitar la conformación de bases de datos de información odontológica, poniendo énfasis en el correcto registro yarchivo por parte del odontólogo en la práctica clínica para contribuir con el accionar de aquellos colegas que se desempeñan como auxiliares de la Justicia.

Forensic Application of HuaxiaTM Platinum Kit / 法医学杂志

OBJECTIVES@#To investigate the genetic polymorphism of 23 autosomal STR loci of Huaxia™ Platinum kit in Chinese Han population, and to evaluate the forensic efficiency of Huaxia™ Platinum kit.@*METHODS@#A total of 500 unrelated healthy individuals from Han population were genotyped with Huaxia™ Platinum kit. The frequency distribution and the parameter of population genetics of STR loci were analysed statistically. Huaxia™ Platinum kit was compared with other 7 commercial STR kits commonly seen at home and abroad in the number of STR loci, interior label, fluorescent mark, total number of alleles in Ladder and system effectiveness.@*RESULTS@#All the 23 autosomal STR loci were consistent with Hardy-Weinberg equilibrium （P>0.05）. The discrimination power was 0.791 5-0.986 2. The polymorphism information content （PIC） was 0.559 0-0.914 0. The combined discrimination power （CDP） was 1-4.1×10⁻²⁸, while combined probability of paternity exclusion in trio （CPET） and in duo （CPED） were 1-4.1×10⁻¹⁰ and 1-8.4×10⁻⁷, respectively. Compared with other 7 kits, Huaxia™ Platinum kit contained the most number of alleles within the Ladder.@*CONCLUSIONS@#All the 23 autosomal STR loci of Huaxia™ Platinum kit with highly polymorphic in Han population can be used for paternity testing and individual identification. Compared with other 7 kits, it appears that Huaxia™ Platinum kit can provide more genetic information.

Construction of a 15-plex Rapid STR Multiplex Amplification System / 法医学杂志

OBJECTIVE@#To establish a 15-plex rapid STR multiplex amplification system.@*METHODS@#Fourteen auto-chromosome loci and one sex-chromosome were selected to compare the situations of allelic losses and nonspecific amplication under different conditions. FastStart Taq DNA polymerase and DNA standard sample 9947A were used during amplification and optimization process.15-plex rapid STR amplification system was achieved by performing various experiments including selection of amplification conditions and the volume of DNA polymerase, adjustment of inter-locus balance, optimization of rapid amplification, screening of reaction buffers, selection of reaction volume, and a variety of additives.@*RESULTS@#Using 10 μL rapid PCR system, including 1 ng DNA templates, 0.4 μL polymerase and 10xFastStart high fidelity reaction buffer, a complete and well-balance DNA profile of 15 STR loci for standard genomic DNA was obtained in 32 minutes, without the allele drop-out and non-specific amplicons. Meanwhile, 5% glycerinum, 0.01% gelatin, 0.05% gelatin and 5 mmol/L ammonium sulfate could be used as the reactive additive during the amplification procedure.@*CONCLUSION@#The 15-plex rapid STR multiplex amplification system can be used to decrease reaction time and enhance sample throughput.