OBJECTIVETo review the common genotyping techniques of Chlamydia trachomatis in terms of their principles, characteristics, applications and limitations.

DATA SOURCESData used in this review were mainly from English literatures of PubMed database. The search terms were "Chlamydia trachomatis" and "genotyping". Meanwhile, data from World Health Organization were also cited.

STUDY SELECTIONOriginal articles and reviews relevant to present review's theme were selected.

RESULTSDifferent genotyping techniques were applied on different occasions according to their characteristics, especially in epidemiological studies worldwide, which pushed the study of Chlamydia trachomatis forward greatly. In addition, summaries of some epidemiological studies by genotyping were also included in this work for reference and comparison.

CONCLUSIONSA clear understanding of common genotyping techniques could be helpful to genotype C. trachomatis more appropriately and effectively. Furthermore, more studies on the association of genotypes of Chlamydia trachomatis with clinical manifestations should be performed.

OBJECTIVETo evaluate the application of different variable number tandem repeats (VNTR) locus in genotyping of Mycobacterium tuberculosis (M.tuberculosis) strains isolated from eight provinces in China, and to find the suitable locus-set of VNTR for epidemical strains in China.

METHODSAll 140 M.tuberculosis strains were randomly selected from 2800 M.tuberculosis strains isolated from eight provinces in China, 27 VNTR loci were used for typing all isolates. Discriminatory power (Hunter-Gaston Index, HGI) of every locus and different locus-set were analyzed by BioNumerics software. Meanwhile, Spoligotyping was used to identify Beijing family and non-Beijing family. Then the HGI of different locus-sets in two families was also evaluated.

RESULTSAll 140 isolates were clustered into Beijing kindred (112 strains, 80%) and non-Beijing kindred (28 strains, 20%) by Spoligotyping. The discriminatory power of Spoligotyping in 140 isolates was 0.4589. Every locus showed different polymorphism and HGI were from 0 to 0.809. The number of VNTR loci with HGI higher than 0.5 in all strains, Beijing family and non-Beijing family was 8, 7 and 14 respectively. 27 loci were combined into four groups which included 8, 12, 15 and 24 VNTR loci respectively. Four locus-sets showed different polymorphism, HGI of eight-locus, 12-locus, 15-locus, and 24-locus set in 140 strains was 0.9991, 0.9882, 0.9980 and 0.9986, and their discriminatory power were calculated in Beijing kindred (HGI: 0.9987, 0.9318, 0.9969 and 0.9975) and non-Beijing kindred (HGI: 1, 0.9894, 1 and 1).

CONCLUSIONDifferent VNTR locus and locus-set showed different discriminatory power in the selected M.tuberculosis strains isolated from China. Eight-locus set can be used in molecular epidemiological study of M.tuberculosis in China after standardization.

OBJECTIVETo investigate the polymorphism of loci DXS6800, DXS6797, GATA172D05, DXS986 four loci in Hebei Han population.

METHODSThe genome DNA of unrelated individuals,the families and rotten materials were extracted with phenol-chloroform method and Chelex-100 method,respectively. The PCR products were detected by the polyacrylamide gel electrophoresis and DNA sequencing analysis.

RESULTSAmong 150 unrelated males and 150 unrelated females from Hebei Han population, 25 alleles were found in the 4 loci. One hundred and thirty-eight haplotypes of the male were detected. The haplotype diversity reached 0.9986.

CONCLUSIONThe findings provided the polymorphic data of DXS6800, DXS6797, GATA172D05, and DXS986 loci in Hebei Han population. The four loci are relatively abundant in polymorphic information for identification and the obtained data of Hebei Han population can be applied to the X-STR genetic data bank.

OBJECTIVE: To evaluate the diversity of combined paternity index (CPI) of multiple STR loci when different population allele frequencies was used to calculate the paternity index. METHODS: CPI of 13 CODIS (combined DNA index system) loci for 108 trio cases and 108 duo cases selected randomly were calculated by using five Chinese Han population allele frequencies, respectively. RESULTS: The CPI range for trio cases and duo cases were 2077.63-50897711626.46 and 25.12-2998685141, respectively. When different population allele frequencies were applied to the same case, the ratio of maximum CPI and minimum CPI, which was more than 100, for trio cases and duo cases were 20 cases (19.52%) and 13 cases (12.04%), respectively. CONCLUSION The variation of CPI value of the CODIS loci was obvious with different allele frequencies. To prevent the error causing by uncertain allele frequencies, a conservative CPI value should be calculated in paternity testing.
Alleles ; China ; DNA Fingerprinting ; Forensic Medicine ; Gene Frequency ; Genetics, Population ; Humans ; Paternity ; Tandem Repeat Sequences/genetics*

OBJECTIVE: To solve the problems of DNA testing in trace sample. METHODS: Applying original carrier method to detect known trace blood DNA and to compare it with the results obtained by high effective DNA extracting method of Chelex-100. RESULTS: The carrier method not only could obtain the right STR genotype in the trace blood sample, but also was twice as sensitive as the Chelex-100 method. CONCLUSION The carrier method could improve the DNA detection in trace sample. It is easy to operate and is much more valuable in the forensic case analysis.
DNA/genetics* ; Genotype ; Humans ; Resins, Synthetic ; Sensitivity and Specificity ; Specimen Handling/methods* ; Tandem Repeat Sequences/genetics*

Using PCR and PAG, followed by silver staining, the tetrameric STR D2S441 locus was studied in 260 unrelated Chinese individuals living in Chengdu. 9 alleles and 26 genotypes were observed. The range of fragment size was 131 bp to 155 bp. The genotype distribution of D2S441 locus in Han population was in accordance with Hardy-Weinberg equilibrium. Family survey confirmed Mendelian inheritance of alleles. The discriminating power (Dp), observed heterozygosity (H), polymorphism information content (PIC) and power of exclusion (PE) were 0.9084, 0.7885, 0.7390 and 0.5778 respectively. The results demonstrated that this locus was highly polymorphic and could be used for forensic identification and paternity testing.
Alleles ; Asian People/genetics* ; China ; Forensic Medicine ; Genetics, Population ; Genotype ; Humans ; Polymorphism, Genetic ; Tandem Repeat Sequences

OBJECTIVE: The genetic polymorphism of two STR loci, D20S85 and D6S477, were studied in 280 unrelated Chinese individuals in Wuhan. METHODS: The PCR amplified products were analyzed by PAGE and silver staining. RESULTS: 10 and 9 alleles were observed in these two STR loci, and the discriminating power (DP) were 0.9085 and 0.9127 respectively. No deviations from Hardy-Weinberg equilibrium were found. The two STR loci had been successfully applied to individual identification and paternity testing. CONCLUSION The results demonstrated that the two loci were useful for forensic identification.
Alleles ; Asian People/genetics* ; China ; Forensic Medicine ; Gene Frequency ; Humans ; Polymorphism, Genetic ; Tandem Repeat Sequences/genetics*

OBJECTIVETo report on a rare allele FGA-13 identified in Guangdong Han population.

METHODSThe rare allele was detected by PCR-STR and DNA sequencing.

RESULTSThe core repeat sequence of rare allele FGA-OL is [TTTC]₃[TTTT][TTCT][CTTT]₅ [CTCC][TTCC]₂, which has been determined as FGA-13.

CONCLUSIONThe rare allele FGA-13 is also present in Guangdong Han population. This is significant for personal identification and paternity testing.

OBJECTIVETo investigate the distribution of CSF1PO, TPOX and TH01 in 5 minority populations only resided in Yunnan province.

METHODSDNA extraction from bloods and multiplex amplification of CSF1PO, TPOX and TH01 were carried out. The technique of denaturing polyacrylamide gel electrophoresis and silver staining method were used.

RESULTSThe data on the distribution of allele frequencies of 3 loci(CSF1PO, TPOX and TH01) in Achang Deang Bulang Pumi and Jino were collected and analyzed.

CONCLUSIONThe allele distribution of the loci were in good agreement with the Hardy-Weinberg equibrium. A satisfactory result was obtained and some significant genetics differences were noticed in different populations.

Tandem-repeated sequence of nucleic acid was constructed by splicing 4 fragments which contain the same sequence in the central part, using overlap extension polymerase chain reaction and then repeatedly cloning it in the same vector at different site of restriction endonuclease. Its signal amplification action was evaluated using electrophoresis of hybridized product and dot hybridization assay. 24-repeat sequence was successfully constructed and confirmed by restriction endonuclease digestion analysis. The construct was 25-repeat actually since the vector itself had the same basic sequence. Hybridized product electrophoresis revealed that the 25-repeat sequence could combine with several secondary probes. Dot hybridization assay demonstrated that tandem-repeated sequence was 16-fold more sensitive than that of non-repeated sequence. Tandem-repeated sequence had good effect on signal amplification. It could be easily cheaply prepared in large amount after cloning. Thus, it might be useful in clinical examinations and biological researches.
Genetic Vectors ; Nucleic Acid Hybridization ; methods ; Polymerase Chain Reaction ; methods ; Tandem Repeat Sequences ; genetics