Formula Derivation for the Probability Distribution of IBS Score in Unrelated Individual Pairs / 法医学杂志

@#Objective To derive the general equation of the probability distribution of identity by state （IBS） score among biological full sibling pairs by calculating STR allele frequency. Methods Based on the Mendelian genetics law and the hypothesis that parents of biological full siblings（FS） were unrelated individuals, the IBS score and corresponding probability of different genotype combinations in the offspring when unrelated individuals of different genotype combinations give birth to two offsprings were derived. Results Given fi （i=1, 2, …, m） as the frequency of the ith allele of a STR locus, the probability of sharing 2 alleles（p2FS）, 1 allele（p1FS） or 0 allele （p0FS） with biological full sibling pairs on the locus can be respectively expressed as follows： p2FS= 14 ×[1 + 2∑im= 1 fi2 + 2（∑im= 1 fi2）2 -∑im= 1 fi4] , p1FS= 12 ×[1 +∑im= 1 fi2 - 2（∑im= 1 fi2）2 - 2∑im= 1 fi3 + 2∑im= 1 fi4] and p0FS= 14 ×[1 - 4∑im= 1 fi2 + 2（∑im= 1 fi2）2 + 4∑im= 1 fi3 -3∑im= 1 fi4] . The sum of p2FS, p1FS and p0FS must be 1. As for the multiple genotyping system that contained n STR loci, IBS scores between biological full sibling pairs conform to binomial distribution：IBS~B（2n, π1）. The population rate π1, can be given by the formula：π1= 1n∑ln= 1 p2FSl + 21n∑ln= 1 p1FSl . Conclusion The alternative hypothesis in biological full sibling testing is that two appraised individuals are biological full siblings. The probability of the corresponding alternative hypothesis of any STR locus combination or IBS score can be directly calculated by the equations presented in this study, and the calculation results are the basis for explanations of the evidence.

Equation Derivation of the Probability Distribution of IBS Score among Full Sibling Pairs / 法医学杂志

Objective To derive the general equation of the probability distribution of identity by state （IBS） score among biological full sibling pairs by calculating STR allele frequency. Methods Based on the Mendelian genetics law and the hypothesis that parents of biological full siblings （FS） were unrelated individuals, the IBS score and corresponding probability of different genotype combinations in the offspring when unrelated individuals of different genotype combinations give birth to two offsprings were derived. Results Given fi （i=1, 2, …, m） as the frequency of the ith allele of a STR locus, the probability of sharing 2 alleles （p2FS）, 1 allele （p1FS） or 0 allele （p0FS） with biological full sibling pairs on the locus can be respectively expressed as follows： (see the text). The sum of p2FS, p1FS and p0FS must be 1. As for the multiple genotyping system that contained n STR loci, IBS scores between biological full sibling pairs conform to binomial distribution： IBS~B（2n, π1）. The population rate π1, can be given by the formula： (see the text). Conclusion The alternative hypothesis in biological full sibling testing is that two appraised individuals are biological full siblings. The probability of the corresponding alternative hypothesis of any STR locus combination or IBS score can be directly calculated by the equations presented in this study, and the calculation results are the basis for explanations of the evidence.

Formula Derivation for the Probability Distribution of IBS Score in Unrelated Individual Pairs / 法医学杂志

OBJECTIVES@#To derive the probability equation given by STR allele frequencies of identity by state （IBS） score shared by unrelated individual pairs.@*METHODS@#By comparing the STR genotypes of two unrelated individuals, three mutually exclusive combinations could be obtained： （1） sharing 2 identical alleles, a₂=1, otherwise a₂=0; （2） sharing 1 identical allele, a₁=1, otherwise a₁=0; （3） sharing 0 identical allele, a₀=1, otherwise a₀=0. And the IBS score of the one STR locus in this unrelated individual pair could be given by the formula： ibs=2a₂+a₁. The probability of a₂=1 （p₂）, a₁=1 （p₁） and a₀=1 （p₀） were derived and expressed in powers of the allele frequencies. Subsequently, for a genotyping system including n independent STR loci, the characteristics of binomial distribution of IBS score shared by a pair of unrelated individuals could be given by p₂l and p₁l （l=1, 2, …, n）.@*RESULTS@#All the general equations of p₂, p₁ and p₀ were derived from the basic conceptions of a₂, a₁ and a₀, respectively. Given fi （i=1, 2, …, m） as the ith allele frequency of a STR locus, the general equations of p₂, p₁ and p₀ could be respectively expressed in powers of fi： [Formula: see text],[Formula: see text] and [Formula: see text]. The sum of p₂, p₁ and p₀ must be equal to 1. Then, the binomial distribution of IBS score shared by unrelated individual pairs genotyped with n independently STR loci could be written by： IBS~B（2n, π）, and the general probability, π, could be given by the formula： [Formula: see text].@*CONCLUSIONS@#In the biological full sibling identification, the probability of null hypothesis corresponding to any specific IBS score can be directly calculated by the general equations presented in this study, which is the basement of the evidence explanation.

Effect of Qiguiyin Decoction on multidrug-resistant Pseudomonas aeruginosa infection in rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of Qiguiyin Decoction, QGYD) on multidrug-resistant Pseudomonas aeruginosa infection in Sprague-Dawley (SD) rats.</p><p><b>METHODS</b>A pseudomonal infection model in SD rats was established by injecting multidrug-resistant P. aeruginosa intraperitoneally. Infected rats were randomized into four groups treated with Pure water, QGYD, ceftazidime, or combined QGYD and ceftazidime. Blood samples were obtained from the abdominal aorta. Serum was then collected and analyzed by peptide array for immune responsiveness to multidrug-resistant beta-lactamase proteins, including Verona integronen-coded metallo-beta-lactamase 1 (VIM-1), Sao Paulo metallo-beta-lactamase 1 (SPM-1), and Temoniera (TEMs). Blood levels of interleukin-1β (IL-1β), interleukin-4 (IL-4), and interferon-γ (IFN-γ) were assessed by enzyme-linked immunosorbent assay.</p><p><b>RESULTS</b>QGYD enhanced antibody reactivity against VIM-1 [epitopes 7-11 and 36-40] and TEM-1 [epitopes 26-27, 52-55, and 66-70]. QGYD treatment restored the compromised antibody reactivity against VIM-1 [epitopes 53-54 and 56-58] and SPM-1 [epitopes 16-19 and 82-85] following pseudomonal infection. Serum levels of IL-1β and Th1/Th2 in the rats were significantly elevated following pseudomonal infection (P<0.05 orP<0.01). In contrast, QGYD and combination QGYD and ceftazidime treatment restored the elevated serum IL-1β and Th1/Th2 levels to normal (P>0.05).</p><p><b>CONCLUSIONS</b>QGYD improves the immune response to pseudomonal infection in rats by stimulating the production of protective antibodies against drug-resistant proteins VIM-1, SPM-1, and TEM-1. In addition, it protects the immune system and maintains immune responsiveness by restoring IL-1β and Th1/Th2 levels.</p>

Forensic application of 30 InDel loci in Han and She nationalities of Eastern China / 法医学杂志

OBJECTIVE@#To evaluate the forensic application value of 30 insertion/deletion (InDel) loci included in Investigator DIPplex Kit in Han and She nationalities of Eastern China.@*METHODS@#A total of 565 unrelated individuals in Han nationality and 119 ones in She nationality of Eastern China were investigated using Investigator DIPplex Kit. Allele frequencies, population genetics parameters of the 30 InDel loci were statistically calculated.@*RESULTS@#In Han nationality, the mean Ho was 0.413 3, the mean DP was 0.551 1, the mean PIC was 0.320 0. And in She nationality, the mean Ho was 0.389 6, the mean DP was 0.543 3, the mean PIC was 0.310 0. No deviation from Hardy-Weinberg equilibrium was observed in Han and She nationalities (P > 0.05).@*CONCLUSION@#The 30 loci in Investigator DIPplex Kit show good genetic diversity in Han and She nationalities, and could be used as a supplemental tool for some special paternity cases.

Development of an 18 X-InDel multiplex PCR system / 法医学杂志

OBJECTIVE@#To investigate Insertion/Deletion (InDel) polymorphism on the X chromosome and to screen 18 InDel loci for the Chinese Han population as a forensic DNA typing system auxiliary.@*METHODS@#Eighteen X-InDel markers were selected using the Human Genome Browser and dbSNP database. Multiplex PCR primer pairs of selected X-InDel markers were designed using Primer 3 software and divided into 3 groups according to the amplified fragment length, labeled by FAM, HEX and TAMRA fluorescence dye, respectively. The population genetics research and comparative analysis of Chinese Han nationality and 4 main minorities, the Hui, Wei, Mongol, and Tibetan nationalities, were investigated with the system.@*RESULTS@#A new multiplex genotyping system, named InDel X-18PLEX, was successfully developed and validated, consisted of 18 X-InDel markers on the X chromosome and 1 Amelogenin gender marker. No deviation from Hardy-Weinberg equilibrium expectations was detected in the distribution of genotypes in the 5 investigated ethnic groups. However, there was significant difference between their distributions. From the investigation of Han nationality, high female (0.9999994) and male (0.999 88) overall discrimination power values were obtained, as well as high overall mean exclusion chance values in trios (0.999 992) and in duos (0.99).@*CONCLUSION@#InDel X-18PLEX meets the requirements as a forensic DNA complementary kit, providing effective supplementary analytical tools for difficult cases.

Messenger RNA profiling for forensic body fluid identification: research and applications / 法医学杂志

Identifying the origin of body fluids left at a crime scene can give a significant insight into crime scene reconstruction by supporting a link between sample donors and actual criminal acts. However, the conventional body fluid identification methods are prone to various limitations, such as time consumption, intensive labor, nonparallel manner, varying degrees of sensitivity and limited specificity. Recently, the analysis of cell-specific messenger RNA expression (mRNA profiling) has been proposed to supplant conventional methods for body fluid identification. Since 2011, the collaborative exercises have been organized by the European DNA Profiling Group (EDNAP) in order to evaluate the robustness and reproducibility of mRNA profiling for body fluid identification. The major advantages of mRNA profiling, compared to the conventional methods, include higher sensitivity, greater specificity, the ability of detecting several body fluids in one multiplex reaction, and compatibility with current DNA extraction and analysis procedure. In the current review, we provided an overview of the present knowledge and detection methodologies of mRNA profiling for forensic body fluid identification and discussed its possible practical application to forensic casework.

Progress in InDel as a new generation of genetic marker / 法医学杂志

As forensic DNA typing experienced three generations of genetic marker researching stage, short tandem repeat (STR) has been widely used in forensic identification as a mature tool. Further exploration of the human genome led to the discovery of polymorphism markers of single nucleotide polymorphism (SNP) and Insertion/Deletion (InDel). InDel, which combines the desirable characteristics of previous genetic markers as a new type of genetic marker, has got extensive concern in fields like medical molecular biology and forensic biology. This paper generally reviews the history of research and the corresponding results of InDel along the line of time axis as well as the different aims of these research focusing on the progress in the multiple amplification system with several InDel as the genetic marker (autosomal or X chromosome) in forensic biology and anthropology. Finally, the direction of research in this field and the problems to be solved have been put forward.

Algorithms of likelihood ratio for discriminating full sibling from half sibling / 法医学杂志

OBJECTIVE@#To derive the formulae for likelihood ratio calculation in discriminating full sibling from half sibling with single-parent participation or without parent participation.@*METHODS@#Null hypothesis and alternative hypothesis were established for discriminating full sibling from half sibling in two circumstances: two children with single-parent and without parent participation. Conditional probabilities of the genetic evidentiary under null and alternative hypotheses were calculated according to the Bayesian theory. The likelihood ratios were established with the conditional probability under alternative hypothesis division that under null hypothesis, followed with simplification. All the formulae were validated in a real case.@*RESULTS@#While mother or fathers' genetic information available in differentiating full sibling from half sibling, 14 different genotype combinations could be shared by the two detected children at a given locus and the likelihood ratio could be calculated with 5 different formulae respectively. While both parents' genetic information unavailable, 11 different genotype combinations could be shared and the likelihood ratio could be calculated with 7 different formulae respectively. It was validated in a real case that the power of the likelihood ratio method developed for discriminating full sibling from half sibling with single-parent participation was higher than that of the ratio of full sibling index over half sibling index.@*CONCLUSION@#The formulae of likelihood ratio developed are useful for discriminating full sibling from half sibling with single-parent participation or without parent participation.

Typing and polymorphism analysis of 16 STR loci on X chromosome / 法医学杂志

OBJECTIVE@#To develop a PCR-based X-STR kit for typing of 16 X-STR loci and investigate the polymorphisms of the X-STR markers.@*METHODS@#Sixteen STR loci (GATA 165B12, DXS101, GATA 172D05, HPRTB, DXS981, DXS8378, DXS6795, GATA 31E08, DXS6809, DXS6803, DXS9902, DXS6807, DXS7423, DXS7133, DXS6810 and DXS7132) located on X chromosome were selected. The primers for multiplex PCR were designed by Primer Premier 5.0 software and labeled by four fluorescences (FAM, HEX, TAMRA and ROX). The developed multiplex PCR system was used for investigating the polymorphisms of the X-STR markers in Han populations.@*RESULTS@#The 16-plex amplification system named IDtyper X-16 was successfully developed and validated. Among the 16 X-STR loci, DXS7133 and DXS7423 were found to be moderately polymorphic and the other 14 X-STR markers were highly polymorphic (P1C > 0.5, H > 0.5). The cumulative discrimination power in females and in males were 0.999 999 999 999 97 and 0.999 999 993 respectively in Han population. The combined power of exclusion in trios and in duos were 0.999 999 93 and 0.999990, respectively.@*CONCLUSION@#The IDtyper X-16 kit is highly valuable in forensic science and is suitable for paternity testing in disputed cases.

Universal algoritihms for paternity index in trios and its extended application / 法医学杂志

OBJECTIVE@#To introduce an universal algorithm for kinship index between a baby and a random person with biologic mother reference.@*METHODS@#Based on the formulas of paternity index in trios (PIT), common factors shared in these formulas were deduced following reconstructions of these formulas with the common factors. Universal algorithms for other common kinship indices, such as grandparental index (GI), half sibling index (HSI), avuncular index (AI) and first cousin index (CI1st), were investigated according to avuncular index rule and the coefficient of relationship (r).@*RESULTS@#The common factor shared in the formulas for PI(T) calculation was 1 plus reciprocal of the frequency of the allele with identity by state between the alleged father and the detected baby. Two general formulas for PI(T), GI, AI, HSI and CI1st with biologic mother reference were successfully established with the common factor and r value.@*CONCLUSION@#The calculation was simplified with the universal algorithms for common kinship indices between random person and the baby with biologic mother reference and the batch arithmetic operation with the universal algorithms can be easily realized with programming.

Establishment of universal algorithms for commonly used kinship indices between two individuals / 法医学杂志

OBJECTIVE@#To establish universal algorithms for commonly used kinship indices between two individuals.@*METHODS@#Based on the formulas of paternity index in duos(PID), full sibling index(FSI), half sibling index (HSI), avuncular index (AI), grandparental index (GI) and first cousin index (CI1st) deduced from ITO method, the common factors, 1 plus reciprocal of the frequency of the allele with identity by state between the two individuals, shared in these formulas were abstracted with induction method, following with reconstruction of these formulas with the common factor and the coefficient of relationship (r).@*RESULTS@#A universal algorithm for PI(D), HSI, AI, GI and CI1st, was developed with the common factor and r value according to the heterozygosity of the two individuals. Meanwhile, a group of two formulas for FSI calculation was also established according to the individuals' heterozygosity.@*CONCLUSION@#The universal algorithms for the 6 types of kinship indices are practical in corresponding kinship determination and the batch arithmetic operation with the universal algorithms can be easily programmed.

Differences of DNA methylation profiles in monozygotic twins' blood samples / 法医学杂志

OBJECTIVE@#To evaluate the potential usefulness of DNA methylation in individual discrimination of monozygotic twins by investigating the differences of DNA methylation profiles in monozygotic twins' blood samples.@*METHODS@#Blood samples from 22 pairs of monozygotic twins were obtained with informed consent. Genomic DNA extracts were bisulfite treated followed by detection with Infinium HumanMethylation27 BeadChip Assays(Illumina, USA). Epigenetic distances between each pair of monozygotic twins and each pair of unrelated individuals of same gender were calculated with Euclidean distance algorithms. Distribution of epigenetic distance in monozygotic twin group was statistically compared with that in unrelated individuals.@*RESULTS@#Difference of epigenetic distance between male and female pairs was not statistically significant in unrelated individual group or in monozygotic twin group (P = 0.0695 and 0.4825, respectively). Epigenetic distance of monozygotic twins was significantly lower than that of unrelated individual pair of same gender (Median: 6.02 vs 7.20, P = 0.0002). However, all the epigenetic distance in monozygotic twin group or in unrelated individuals were significantly higher than 4.00 (P < 0.000 1).@*CONCLUSION@#DNA methylation profiles of monozygotic twin's blood samples were significantly different with each other, which was similar to that in unrelated individuals of same gender. These results indicated that DNA methylation was a useful biomarker in individual discrimination of monozygotic twins.

A primary study of criterion for source identification of gastrointestinal tumor sample with Identifiler multiplex system / 法医学杂志

OBJECTIVE@#To investigate the criterion for source identification of gastrointestinal tumor based on the number of identical allele (IAn) and the number of matched STR locus with 2 identical alleles (A2) in Identifiler system.@*METHODS@#One hundred and five pairs of gastrointestinal tumor samples and homologous normal samples (TN group) were genotyped with Identifiler system. The numbers of STR locus with genotypic alteration (STRGA) in each tumor were determined by comparing the genotype of the matched STR loci in each pair of samples. According to the limited distribution of IAn and A2, 16 different values of IAn was substituted into the published discriminant functions to obtain the cut-off values of IAn and A2 for source identification of tumor sample. Indices including sensitivity (SEN), specificity (SPE), accuracy (AC), positive predictive value (PPV) and negative predictive value (NPV) for distinguishing tumor from an unrelated individual or a full sibling of the patient were calculated. Concordance of the identification results based on the determined criteria and the definite facts were statistically tested with Kappa index.@*RESULTS@#The total frequency of STRGA was 5.46%. There were 31.43% of the 105 tumor samples carried at least one STR locus with STRGA mutation. According to the Fisher discrimination rules, criteria I (IAn>or=23 and A2>or=8) and criteriall (IAn>or=26 and A2>or=11) meet the requirements of distinguishing tumor sample from an unrelated individual or a full sibling of the patient with tumor, respectively. SEN=0.971 0, PPV=1.000 0, PPV=0.891 9 and Kappa=0.923 5, when the criteria were used to determine the specified relatives.@*CONCLUSION@#Criteria I and criteria II were powerful for distinguishing tumor sample from an unrelated individual or a full sibling of the patient with tumor, respectively, when the Identifiler system was adopted for source identification of gastrointestinal tumor sample.

A primary study for criteria of full sibling determination with Identifiler system / 法医学杂志

OBJECTIVE@#To investigate the criteria of the number of identical allele (IAn) and the number of matched STR locus with 2 identical alleles (A2) for full sibling (FS) determination with Identifiler system.@*METHODS@#According to the limited distribution of IAn. and A2, all of the 31 potential values of IAn. were substituted into the published discriminant functions to obtain the cut-off values of IAn and A2 for FS determination, and then 4 different criteria were determined to distinguish 280 FS pairs from 2283 individual pairs, respectively, which had been genotyped with Identifiler system. Cumulative full sibling index (CFSI) of the samples were calculated with ITO method, and 4 different criteria of CFSI (>1, > or =5, > or =20 and > or =100) were also utilized to determinate FS, respectively. Indices including sensitivity (SEN), specificity (SPE), accuracy(AC), positive predictive value(PPV) and negative predictive value (NPV) of the 8 different criteria for FS determination were calculated, respectively. Concordance of FS determination between the criteria based on IAn and A2 and that of CFSI were statistically tested with Kappa index.@*RESULTS@#All the individual pairs, which meet the requirement of (I) IAn > or =15 and A2 > or =4, or (II) IAn > or =16 and A2 > or =3, or (III) IAn > or = 17 and A2 > or =3, or (IV) IAn > or =18 and A2 > or =3, could been concluded as FS. AC, SPE and NPV of the 4 criteria mentioned above and the 4 criteria of CFSI were all over 0.9500 in FS determination. Indices between criterion II and CFSI > or =5, criterion III and CFSI > or =20, criterion IV and CFSI > or =100 were similar with each other and the Kappa indexes of the 3 groups were 0.9049, 0.9204 and 0.9083, respectively. PPV and NPV of criterion III and CFSI > or =20 were all over 0.9500.@*CONCLUSION@#The criterion of IAn > or =17 and A2 > or =3 was feasible and efficient for FS determination with Identifiler system, power of which was similar with the criterion of CFSI > or =20.

Effect of urinary trypsin inhibitor on DNA genotyping in urine samples / 法医学杂志

OBJECTIVE@#To study the effect of urinary trypsin inhibitor (UTI) on STR genotyping with urinary samples.@*METHODS@#Midstream urine samples of 5 male and 5 female volunteers were collected respectively, sub-packaged, added with different concentration of UTI and stored at -80 degrees C. Genomic DNA was extracted from those urinary samples, of which STR profiles were genotyped with IdentifilerTM kit at 8 different time points. Results of genotyping in urinary samples were compared with those of the homogenous blood control samples and the successful rate of genotyping in different group of urinary samples treated with UTI was determined.@*RESULTS@#Fifteen STR loci included in Identifiler system were all detected in control blood samples and urinary samples stored for 1 day. STR locus loss was observed and all 15 STR loci disappeared in female urinary samples untreated with UTI while those storage periods prolonged to 3 and 9 days, respectively. However, all 15 STR loci could be detected in female urinary samples treated with UTI and stored for as long as 9 days. No STR loci could be detected in male urinary samples preserved without UTI for 7 days while 9 STR loci detected preserved with UTI for 9 days. There was no significant difference among the average detection ratios of STR loci in female urinary samples treated with UTI at concentrations of 0.2, 0.4 or 0.6 microg/mL and stored for 30 days, mean of which was as high as 0.8400 +/- 0.0423, statistically higher than that in male urinary samples (0.1600 +/- 0.0423).@*CONCLUSION@#Detection rate of STR loci in urinary samples preserved with UTI was increased significantly, which results in prolonging the storage periods of urinary samples for personal identification.

InDel_typer30: a multiplex PCR system for DNA identification among five Chinese populations / 法医学杂志

OBJECTIVE@#To develop a multiplex PCR system, using insertion/deletion (InDel) polymorphism markers, for forensic DNA identification among Han, Hui, Uighur, Mongolian and Tibetan populations in China.@*METHODS@#Highly polymorphic InDel markers from human autosomes were selected using the Human Genome Browser in Galaxy system and dbSNP database. Multiplex PCR primer pairs of selected InDel markers were designed using Primer 3 software. The multiplex PCR system was developed using a five fluorescence dye labeling system. Genetic polymorphisms of selected InDel markers were investigated using the multiplex PCR system among five populations in China.@*RESULTS@#A new multiplex genotyping system, named InDel_typer30, was successfully developed and validated in this study. The InDel_typer30 system consisted of 30 highly polymorphic InDel markers and 1 Amelogenin gender marker. The average expected heterozygosity of the 30 InDel markers was 0.464, 0.460, 0.453, 0.466 and 0.469 for the Han, Hui, Uighur, Mongolian and Tibetan populations, respectively. The average discrimination power was 0.595, 0.585, 0.586, 0.589 and 0.595 for the Han, Hui, Uighur, Mongolian and Tibetan populations, respectively. The cumulative discrimination power (CDP) were all above 0.999 999 999 996 for the 5 populations.@*CONCLUSION@#InDel_typer30 was a useful forensic DNA identification tool for human identification among Han, Hui, Uighur, Mongolian and Tibetan populations in China.

Application of multiple polymorphism genetic markers in determination of half sibling sharing a same mother / 法医学杂志

OBJECTIVE@#Determination strategies for half sibling sharing a same mother were investigated through the detection of autosomal and X-chromosomal STR (X-STR) loci and polymorphisms on hypervariable (HV) region of mitochondrial DNA (mtDNA).@*METHODS@#Genomic DNA were extracted from blood stain samples of the 3 full siblings and one dubious half sibling sharing the same mother with them. Fifteen autosomal STR loci were genotyped by Sinofiler kit, and 19 X-STR loci were genotyped by Mentype Argus X-8 kit and 16 plex in-house system. Polymorphisms of mtDNA HV-I and HV-II were also detected with sequencing technology.@*RESULTS@#Full sibling relationship between the dubious half sibling and each of the 3 full siblings were excluded based on the results of autosomal STR genotyping and calculation of full sibling index (FSI) and half sibling index (HIS). Results of sequencing for mtDNA HV-I and HV-II showed that all of the 4 samples came from a same maternal line. X-STR genotyping results determined that the dubious half sibling shared a same mother with the 3 full siblings.@*CONCLUSION@#It is reliable to combine three different genotyping technologies including autosomal STR, X-STR and sequencing of mtDNA HV-I and HV-II for determination of half sibling sharing a same mother.

Identification of sibling sisters using STR and SNP / 法医学杂志

OBJECTIVE@#The methods for identification of sibling sisters were explored with detection of genetic markers on autochromosome and X-chromosome.@*METHODS@#Genomic DNA of the sibling sisters were extracted, and 15 STRs on autochromosome and 17 STRs on X-chromosome were genotyped by Sinofiler kit, Mentype Argus X-8 kit and in-house kit of X-STRs, respectively. 11 X-SNPs were genotyped with TaqMan technology.@*RESULTS@#Full sibling relationship of the test samples were confirmed by calculating full sibling index of STRs in autochromosome, which were also supported by the detection of 1-2 same alleles at each locus on X-chromosome.@*CONCLUSION@#In identification of full sibling sister, not only STRs on autochromosome but also polymorphism genetic markers in X-chromosome can be utilized.

Source identification of gastric cancer tissue with discriminatory analysis / 法医学杂志

OBJECTIVE@#To evaluate discriminatory analysis on source identification of gastric cancer tissue based on the number of matched STR locus or identical allele.@*METHODS@#Twenty two pairs of fresh gastric cancer tissue and homologous normal tissue were genotyped with Identifiler kit. Frequencies of STR genotypic alteration (STR(GA)), the number of matched STR locus without identical allele (A0), with 1 identical allele (A1), or with 2 identical alleles (A2) and the number of total identical alleles (IAn) were calculated with counting method. A1, A2 and IAn were evaluated with Fisher discriminant functions to determine the source of each gastric cancer tissue. Effectiveness of the identification of gastric cancer tissue was evaluated with error rate.@*RESULTS@#The total frequency STR(GA) was 3.03% (95% CI: 1.46%-4.88%). There were 31.38% (95% CI: 13.86%-54.87%) of gastric cancer samples carried at least one STR locus with STRGA. It was confirmed by the Fisher discriminant functions that each of the 22 gastric cancer tissue samples came from its homologous normal tissue with an error rate of 0.00%.@*CONCLUSION@#Frequency of STRGA in gastric cancer tissue was high. Fisher discriminant functions based on the number of identical alleles or matched STR loci could be a feasible method for source identification of body for gastric cancer tissue samples.