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.
Africa ; Criminals ; DNA/genetics* ; DNA Fingerprinting/methods* ; Forensic Genetics/methods* ; Genetics, Population ; Humans ; Phylogeography ; Polymorphism, Single Nucleotide

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.
Beijing ; China ; Forensic Genetics/methods* ; Gene Frequency ; Genetics, Population ; Humans ; INDEL Mutation ; Phylogeny

Human leukocyte antigen (HLA) is the most polymorphic genetic system found in human genome. The polymorphisms of different HLA genes and haplotypes in different ethnic and geographic populations are of high importance for investigation of their population genetic characteristics and searching for HLA matched unrelated hematopoietic stem cell transplantation donors, as well as in disease association studies. The HLA molecular genetic principals and the progress of HLA population investigation were reviewed, as well as the methods applied in the field.
Alleles ; Genetics, Population ; methods ; HLA Antigens ; genetics ; Haplotypes ; Humans ; Linkage Disequilibrium

OBJECTIVE: To evaluate the power of Identifiler System for paternity testing. METHODS: A total of 3 277 paternity testing cases were studied using Identifiler System. The exclusion power and mutation rates of the Identifiler System were analysed in the paternity testing. RESULTS: The cumulated power of exclusion was 0.999 998 827, and the cumulated discriminating power was 0.999 999 999 999 999 98, respectively. Of the 3 277 cases, paternity was confirmed in 2 863, but excluded in 347. Among this paternity testing, mutations involving a single STR locus were observed in 65 cases, while mutations involving 2 STR loci were observed in 2 cases. CONCLUSION The Identifiler System is powerful and reliable for paternity testing.
Alleles ; China ; DNA Fingerprinting/methods* ; Forensic Genetics/methods* ; Genetic Testing/methods* ; Genetics, Population ; Humans ; Microsatellite Repeats ; Mutation ; Paternity ; Polymerase Chain Reaction/methods* ; Probability ; Tandem Repeat Sequences/genetics*

OBJECTIVES: To recognize the possibility of Y fragment deletion of Amelogenin gene intuitively and simply according to the genotyping graphs. METHODS: By calculating the ratio of total peak height of genotyping graphs, the statistics of equilibrium distribution between Amelogenin and D3S1358 loci, Amelogenin X-gene and Amelogenin Y-gene, and different alleles of D3S1358 loci from 1 968 individuals was analyzed after amplified by PowerPlex^® 21 detection kit. RESULTS: Sum of peak height of Amelogenin X allele was not less than 60% that of D3S1358 loci alleles in 90.8% female samples, and sum of peak height of Amelogenin X allele was not higher than 70% that of D3S1358 loci alleles in 94.9% male samples. CONCLUSIONS The result of genotyping after amplified by PowerPlex^® 21 detection kit shows that the possibility of Y fragment deletion should be considered when only Amelogenin X-gene of Amelogenin is detected and the peak height of Amelogenin X-gene is not higher than 70% of the total peak height of D3S1358 loci.
Alleles ; Amelogenin/genetics* ; Asian People/genetics* ; DNA Fingerprinting/methods* ; Female ; Genotype ; Humans ; Male ; Mutation ; Polymerase Chain Reaction/methods* ; Population Groups

OBJECTIVE: To establish and evaluate the method of full sibling identification based on the number of allele shared among autosomal STR Loci. METHODS: Two hundred and eighty full sibling pairs and 2,003 unrelated individual pairs were genotyped in 15 STR loci with Identifiler Kit, and the number of allele shared among the 15 STR loci (S15) and full sibling index (FSI) were calculated. Fisher discriminant functions were established with SAS 8.2 software based on S15, the power of which were compared with ITO method. RESULTS: The distribution of S15, in full sibling pair group and unrelated individual pair group were in accord with normal distribution. The established Fisher discriminant functions for each group were Z(FS)= 3.26970S15-31.51174 and Z(UI)=1.70058S15-8.524 11, respectively. The average error of probability in sibling and unrelated pair group was 0.0298. There was no statistically significant difference on the power of full sibling discriminant between the method based on the number of allele shared among the 15 STR loci or the CODIS 13 STR loci and the ITO method. CONCLUSION The method based on the number of allele shared among the 15 STR loci in full sibling identification is convenient, credible, easy to handling and unaffected by the allele frequency of STR loci.
Alleles ; Chromosomes, Human ; Forensic Genetics ; Gene Frequency ; Genetics, Population ; Genotype ; Humans ; Polymerase Chain Reaction/methods* ; Siblings ; Tandem Repeat Sequences/genetics*

OBJECTIVETo solve the problems in the accuracy and standardization of short tandem repeats-polymerase chain reaction (STR-PCR) typing, the authors adopted the molecular clone technology in producing the standard allelic ladders of D1S1676, D2S2735, D11S1977 and D22S444 loci and applied them in a population study on the Hans in Chengdu, China.

METHODSPCR was used to produce several different allelic fragments of these loci. PCR products were eluted from the gel and re-amplified by PCR. The purified allelic fragments were then blunt-end subcloned individually into the pGEMR-T plasmid vectors and the recombinant were transfected into competent E.coli DH5alpha TM cells. The results of sequencing confirmed that the size and the construction of the inserts were correct. The recombinant plasmids DNA with the inserts were then used as template for re-amplification to generate the four loci standard ladders.

RESULTSThe authors succeeded in producing large quantity of standard allelic ladder of these four loci, with which the genetic polymorphisms of these loci in Chengdu Han population of China were studied.

CONCLUSIONThis method is of high value for forensic DNA typing to construct standard ladders. D1S1676, D2S2735 loci are robust for forensic analysis in Chinese Han population, whereas the value of D11S1977 and D22S444 loci is limited.

Alleles ; Asian Continental Ancestry Group ; genetics ; China ; Genetics, Population ; methods ; Humans ; Microsatellite Repeats ; genetics ; Polymerase Chain Reaction ; Polymorphism, Genetic

OBJECTIVE: To establish the rapid PCR amplification program and system and to verify the technical indexes. METHODS: PCR multiplex and capillary electrophoresis detection of 24 autosomal STR loci and one Y-STR loci using the 6-color fluorescence marking technology, as well as A melogenin and Y-InDel. Meanwhile, sensitivity, specificity, identity, stability, mixing and a batch of sample tests were investigated, and the genotype of various routine samples and degraded, exfoliated cell samples were observed. RESULTS: The sensitivity of the system was 0.062 5 ng. In addition, the genotype could be detected accurately only around 65 min via rapid amplification. The species-specificity was high and the genotyping of all kinds of dry blood specimens of filter paper and mixed, degraded, exfoliated cell samples were accurate. CONCLUSION The rapid amplification system can significantly improve the detection rate, and obtain accurate and stable genotyping results, which may be important implications for the establishment of STR database and study on population genetics and forensic identification.
Electrophoresis, Capillary ; Fluorescence ; Genetics, Population ; Genotype ; Humans ; Microsatellite Repeats ; Multiplex Polymerase Chain Reaction/methods* ; Sensitivity and Specificity

OBJECTIVE: To investigate the genetic data of 12 autosomal STR loci included in Investigator HDplex kit and to evaluate its forensic application in Han nationality of Eastern China. METHODS: A total of 484 unrelated healthy individuals in Han nationality of Eastern China were investigated with Investigator HDplex kit. Allele frequencies, population genetics parameters and linkage disequilibrium information of the 12 autosomal STR loci were statistically analyzed. RESULTS: No deviations from Hardy-Weinberg equilibrium were detected and all loci were independent form each other within the studied 484 unrelated healthy individuals. DP values of the 12 autosomal STR loci were all above 0.8, and CDP was 0.999 999 999 92. The cumulative probability of paternity exclusion in duo and in trio were 0.999 82 and 0.999 998 6, respectively. CONCLUSION Investigator HDplex kit with 12 highly polymorphic STR loci in Han nationality of Eastern China could be used effectively for forensic DNA genotyping.
Alleles ; Asian People/genetics* ; China ; Ethnicity/genetics* ; Forensic Genetics/methods* ; Gene Frequency ; Genetic Loci/genetics* ; Genetic Markers/genetics* ; Genetics, Population ; Genotype ; Humans ; Mutation ; Polymorphism, Genetic ; Reagent Kits, Diagnostic

OBJECTIVE: To investigate the genetic data of 21 autosomal STR included in Goldeneye™ DNA ID 22NC Kit in Chinese Han nationality and to evaluate the forensic application. METHODS: By detected 500 unrelated healthy individuals in Chinese Han nationality of East China with Goldeneye™ DNA ID 22NC Kit, allele frequencies, population genetics parameters and linkage disequilibrium information of the 21 autosomal STR were statistically analyzed. RESULTS: In the 21 autosomal STR, no deviations from Hardy-Weinberg equilibrium were detected and all loci were independent form each other. DP values of 21 autosomal STR were all above 0.85, and the combined discrimination power was 1-3.616 5 x 10(-26). Combined mean exclusion chance of this system in duo cases was 1-2.786 81 x10(-6), in trio cases was 1-8.545 82 x 10(-1). CONCLUSION Twenty-one autosomal STR included in Goldeneye™ DNA ID 22NC Kit are highly polymorphic in the Han nationality. Combined with Goldeneye™ DNA ID 20A Kit, the kit can satisfy the needs for full-sibling testing and facilitate the solution of this kind of case tools.
Alleles ; Asian People/genetics* ; China ; Ethnicity/genetics* ; Forensic Genetics/methods* ; Gene Frequency ; Genetic Loci/genetics* ; Genetic Markers/genetics* ; Genetics, Population ; Genotype ; Humans ; Polymorphism, Genetic ; Reagent Kits, Diagnostic