Optimization and Developmental Validation of 38-plex InDel Panel for Ancestry Inference / 法医学杂志

OBJECTIVES@#The previously established 38-plex InDel system was optimized and its performance was validated according to the Scientific Working Group on DNA Analysis Method (SWGDAM) application guidelines. The ancestry inference accuracy of individuals from East Asian, European, African and mixed populations was verified.@*METHODS@#DNA standard sample 9947A was used as the template to establish the optimal amplification conditions by adjusting primer balance, Mg2+ final concentration and optimizing PCR thermal cycle parameters and amplification volume. The allelic dropout, nonspecific amplification and whether the origin of the inferred samples matched the known information were compared to evaluate the performance of this system.@*RESULTS@#The optimal dosage of this system was 0.125-2 ng DNA template. The results of InDel typing were accurate, the amplification equilibrium was good, and the species specificity was good. This system showed certain tolerance to DNA samples including the inhibitor such as hemoglobin (≤80 μmol/L), indigo (≤40 mmol/L), calcium ion (≤1.0 mmol/L), and humic acid (≤90 ng/μL). The system enabled the direct amplification of DNA from saliva and blood on filter paper, and the results of ethnic inference were accurate. The system successfully detected the mixed DNA sample from two individuals. The test results of the system for common biological materials in practical cases were accurate.@*CONCLUSIONS@#The results of the 38-plex InDel system are accurate and reliable, and the performance of the system meets the requirement of the SWGDAM guidelines. This system can accurately differentiate the ancestry origins of individuals from African, European, East Asian, and Eurasian populations and can be implemented in forensic practice.

Establishment of Multiplex Amplification System of STR Loci in Felis Catus and Its Forensic Application / 法医学杂志

OBJECTIVES@#To construct a Felis catus STR loci multiplex amplification system and to evaluate its application value by testing the technical performance.@*METHODS@#The published Felis catus STR loci data were reviewed and analyzed to select the STR loci and sex identification loci that could be used for Felis catus individual identification and genetic identification. The fluorescent labeling primers were designed to construct the multiplex amplification system. The system was validated for sensitivity, accuracy, balance, stability, species specificity, tissue identity and mixture analysis, and investigated the genetic polymorphisms in 145 unrelated Felis catus samples.@*RESULTS@#Sixteen Felis catus autosomal STR loci and one sex determining region of Y (SRY) were successfully selected, and constructed a multiplex amplification system containing the above loci. The complete profile of all alleles could still be obtained when the amount of DNA template was as low as 0.25 ng. There was no specific amplification peak in other common animal samples. Population genetic surveys showed that total discrimination power (TDP) of the 16 STR loci was 1-3.57×10-20, the cumulative probability of exclusion (CPE) was 1-6.35×10-5 and the cumulative probability of matching was 3.61×10-20.@*CONCLUSIONS@#The Felis catus STR multiplex amplification system constructed in this study is highly sensitive, species-specific, and accurate in typing results, which can provide an effective solution for Felis catus species identification, individual identification and kinship identification in the field of forensic science.

A novel 6-dye STR 25-plex DNA typing system for forensic casework and databases / 中国法医学杂志

To develop and validate a novel 6-dye STR(short tandem repeat) 25-plex DNA typing system for forensic DNA profiling and databases. In this study, a novel STR 25-plex DNA typing system that includes 24 autosomal STRs (D1S1656, D2S1338, D2S441, D3S1358, D5S818, D6S1043, D7S820, D8S1179, D10S1248, D12S391, D13S317, D16S539, D18S51, D19S433, D21S11, D22S1045, CSF1PO, FGA, Penta D, Penta E, TH01, TPOX, vWA, D11S4463) and Amelogenin was developed. Validation studies demonstrated the sensitivity, accuracy, and reproducibility of our novel STR 25-plex DNA typing system. The sensitivity of the STR 25-plex DNA typing system was demonstrated by the ability to obtain complete profiles from as little as 0.125ng of human DNA. Specificity testing was demonstrated by the lack of cross-reactivity to a variety of commonly encountered animal species and microbial pool. For stability testing, full profiles were obtained with humic acid concentration ≤60ng/μL and hematin ≤600μM. For forensic evaluation, the selected 24 autosomal STRs followed the Hardy–Weinberg equilibrium. Since 24 autosomal STRs were independent from one another, PM (Probability matching) was 3.5434×10-28, TDP (Total Probability of Discrimination Power) was 0.999999999999999999999999969863, and CEP (Cumulative probability of exclusion) was 0.99999999375. The new STR 25-plex typing system is sensitive, reproducible, and stable, therefore it is highly applicable for use in national DNA database and can help to facilitate international data sharing.

Development of a Fluorescence Multiplex Amplification System with 24 Y-STR Loci / 法医学杂志

Objective To establish a novel multiplex amplification system which comprises 24 Y-STR loci.Methods Total 24 Y-STR gene loci, concluding DYS531,DYS630,DYS622,DYS552,DYS510, DYS449, DYS459a/b, DYS446, DYS443, DYS635, DYS587, DYS527a/b, DYS460, Y-GATA-A10, DYS520, DYS557,DYS522,DYS481,DYS570,DYS385a/b,DYS444, were chosen for establishing the fluorescence multiplex amplification system. The specificity, identity, sensitivity, balance of the amplification, anti-in-terference and accuracy of the system were detected and the gene diversity was investigated in the popu-lation of Guangdong.Results No band was found in nonhuman and female samples that were tested by the established multiplex amplification system. The same genotyping results were obtained from different tissues of the same person. Complete profiles could be obtained from more than 0.1 ng of the standard sample 9948. The loss of alleles was found when the common inhibitors such as hemoglobin and calci-um ion were added 120-200μmol/L and 1.5-2.0 mmol/L respectively to the system which with a strong anti-interference to the indigo, humic acid and EDTA. The typing of 24 Y-STR system could give the reliable results when 146 unrelated male individuals were detected and compared with the Yfiler system parallelly. The haplotype diversity(HD)of the population in Guangdong reached 0.99972 that was better than the result retained from Yfiler system, which the HD was 0.99858.Conclusion The fluorescence amplification system with 24 Y-STR loci established in present study has a wildly application prospect and can be used for cases inspection, paternity tests and Y-STR database construction.

Development of a Fluorescence Multiplex Amplification System with 24 Y-STR Loci / 法医学杂志

OBJECTIVES@#To establish a novel multiplex amplification system which comprises 24 Y-STR loci.@*METHODS@#otal 24 Y-STR gene loci, concluding DYS531, DYS630, DYS622, DYS552, DYS510, DYS449, DYS459a/b, DYS446, DYS443, DYS635, DYS587, DYS527a/b, DYS460, Y-GATA-A10, DYS520, DYS557, DYS522, DYS481, DYS570, DYS385a/b, DYS444, were chosen for establishing the fluorescence multiplex amplification system. The specificity, identity, sensitivity, balance of the amplification, anti-interference and accuracy of the system were detected and the gene diversity was investigated in the population of Guangdong.@*RESULTS@#No band was found in nonhuman and female samples that were tested by the established multiplex amplification system. The same genotyping results were obtained from different tissues of the same person. Complete profiles could be obtained from more than 0.1 ng of the standard sample 9948. The loss of alleles was found when the common inhibitors such as hemoglobin and calcium ion were added 120-200 μmol/L and 1.5-2.0 mmol/L respectively to the system which with a strong anti-interference to the indigo, humic acid and EDTA. The typing of 24 Y-STR system could give the reliable results when 146 unrelated male individuals were detected and compared with the Yfiler system parallelly. The haplotype diversity （HD） of the population in Guangdong reached 0.999 72 that was better than the result retained from Yfiler system, which the HD was 0.998 58.@*CONCLUSIONS@#The fluorescence amplification system with 24 Y-STR loci established in present study has a wildly application prospect and can be used for cases inspection, paternity tests and Y-STR database construction.

Diagnóstico molecular de enfermedades genéticas: del diagnóstico genético al diagnóstico genómico con la secuenciación masiva / Molecular diagnosis of genetic diseases: from genetic to genomic diagnosis using next generation sequencing

En la actualidad se conocen 8.000 enfermedades genéticas monogénicas. La mayoría de ellas son heterogéneas, por lo que el diagnóstico molecular por técnicas convencionales de secuenciación suele ser largo y costoso debido al gran número de genes implicados. El tiempo estimado para el diagnóstico molecular se encuentra entre 1 y 10 años, y este retraso impide que los pacientes reciban medidas terapéuticas y de rehabilitación específicas, que sus familiares entren en programas preventivos y que reciban asesoramiento genético. La secuenciación masiva está cambiando el modelo de diagnóstico molecular de los afectos, sin embargo, los médicos y profesionales de la salud se enfrentan al dilema de la selección del método más eficiente, con el menor coste sanitario y con la mayor precisión de sus resultados. El objetivo de este trabajo es revisar la tecnología de secuenciación masiva y definir las ventajas y los problemas en su utilización.

Currently 8000 monogenic genetic diseases are known. Most of them are heterogeneous, so their molecular diagnosis by conventional sequencing techniques is labour intensive and time consuming due to the large number of genes involved. The estimated time is between 1 and 10 years for molecular diagnosis and this delay prevents patients from receiving therapy and rehabilitation measures, and their families from entering prevention programs and being given genetic counselling. Next generation sequencing (NGS) is changing the model of molecular diagnosis of patients; however, doctors and health professionals are faced with the dilemma of choosing the most efficient method, with lower health care costs and the most accurate results. The aim of this paper is to review the NGS technology and define the advantages and problems in the use of this technology.

Application of multiplex amplification of STRs for monitoring survival of engraftment after bone marrow transplantation / 临床检验杂志

Objective To evaluate the application of fluorescent multiplex amplification of short tandem repeat(STR)for monitoring survival of engraftment after bone marrow transplantation(BMT).Methods Three STR loci named D12S391,D18S865 and D20S161 in 56 cases were detected by fluorescent multiplex amplification.PCR products were separated and typed by DNA Sequencer.Results The genotypes of STR in 52 recipient after bone marrow transplantation were completely identical with those of the donors.In another 4 cases the evidences of mixed chimerism were observed.Conclusion The system of fluorescent multiplex amplification of STRs exhibited high capacity of discrimination and low cost.Its application in the detection of STR after BMT is reliable,sensitive and simple.Combined with the clinical manifestation it can be used to evaluate the effect of BMT.