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Mutations at 17 STR loci in Chinese population.

Knowledge about mutation rates and the mutational process of short-tandem-repeat (STR) or microsatellite loci used in forensic analysis is crucial for the correct interpretation of resulting genetic profiles. We analysed a total of 19,754 samples from 6532 paternity testing cases at 17 STR loci which are commonly applied to forensics. The parenthood in each of these cases was highly validated (probability>99.99%). We identified 178 mutations. Locus-specific mutation rate estimates varied between 7.0 x 10(-5) and 2.2 x 10(-3), and the overall average mutation rate estimate was 8.4 x 10(-4). The observed mutational features for STRs have important consequences for forensic application such as the definition of criterions for exclusion in paternity testing and the interpretation of DNA profiles in identification analysis. In order to enrich the reference data of STRs mutations which are valuable for forensic application, we suggest the establishment of such database and ask the whole forensic community for data contribution including China.

China↗

Characterization of four microsatellites in an Italian population and their application to paternity testing.

Microsatellites have recently been used for linkage analysis of genetic diseases and for DNA fingerprinting in forensic medicine. In the present study the heterozygosity, PIC values and allele distributions of four microsatellites, D8S85, D8S88, D5S346 and D7S460, in an Italian population have been investigated. After amplification with primers specific for each locus, alleles were separated and detected by denaturing gel electrophoresis and ethidium bromide staining. High heterozygosity and PIC values were observed for all microsatellites in accordance with data in other Caucasian populations. However, different allele distributions for D8S85, D8S88 and D5S346, due to the presence of additional bands or to different frequencies, were found. D7S460, which has never been fully characterized before, appeared to have five alleles in the range 172 to 188 bp. When used for paternity testing, all microsatellites gave results which were consistent with those obtained with established markers, including apo B 3'HVR, D1S80 and COL2A1. This indicates that D8S85, D8S88, D5S346 and D7S460 may be useful as additional informative markers or for solving discrepancies in selected cases.

Alleles↗

An analysis of two polymorphic points of the 7th intron of human p53 gene.

OBJECTIVE: To detect polymorphic points of the 7th intron of human p53 oncogene. METHODS: Polymerase chain reaction (PCR) and double- strand DNA direct sequencing were used to analyse sequence alteration of p53 intron 7. One hundred and five cases of normal human peripheral blood samples with no genetic relation were investigated. RESULTS: There were two polymorphic points in the 7th intron of p53 gene. The first one was localized at 73 base pair (bp) to 3'-end of exon 7; the other one at 93. Three genotypes were found. Twenty-two cases were of type TG, 37 cases were of type CT, and the other 46 cases were of heterozygote. Because the first point was alteration of GGGCCC to GGGTCC or its heterozygote, it had a point alteration of enzyme Apa I. CONCLUSION: There are two polymorphic points in the 7th intron of human p53 gene, which may be of importance to identification of individual genetic relation and to judging of a case in forensic medicine.

Genes, p53↗

[Polymorphism of X-STR loci DXS7108 and DXS1196 in the Northern Polish population].

This paper describes results of a population study of two X-linked STR microsatellite markers: DXS7108 and DXS1196. 298 samples of DNA of unrelated persons (male and female) from the Northern part of Poland were analyzed. DNA was isolated using a non-enzymatic method. After amplification PCR products were separated by means of capillary electrophoresis using the ABI PRISM 310 Genetic Analyzer. The most common alleles of each locus were sequenced and used as a control ladder to type unknown samples. Testing for Hardy-Weinberg equilibrium (HWE) showed no significant deviation for these two loci. Statistical parameters (PD, HET, MEC) showed that examined systems are useful in forensic medicine.

Adult↗

Comparison of DNA extraction from blood stain and decomposed muscle in STR polymorphism analysis.

Forensic samples that are often degraded and limited in quality cause DNA typing analysis by conventional methods unsuitable. We performed a single tube-multiplex PCR on 9 STR loci (D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S820) and the X-Y homologous gene amelogenin of DNA extracted from six week postmortem blood stain and decomposed muscle by using QIAGEN QIAamp blood or tissue procedure. An automated genetic analyzer based on fluorescent dye technology was used to detect STR allele patterns. The DNA profile of blood stain sample obtained a complete and unambiguous pattern, whereas, that of muscle DNA extracted from QIAamp tissue and Chelex plus QIAamp blood protocols showed detected STR alleles for 70 per cent and 50 per cent of all tested alleles, respectively. The degraded muscle DNA could not yield amplified products of large size STR alleles; CSF1PO, D13S317 and D7S820. However, the analysis which relied upon the PCR-based STR polymorphism analysis and automated genetic analyzer system offers an ideal strategy for forensic identification.

Autopsy↗

Population genomics: a bridge from evolutionary history to genetic medicine.

Studies of human genetic variation are making contributions in several key areas. Evolutionary genetic studies yield critical clues about the histories of human populations, and they provide substantial support for an African origin of modern humans. The analysis of genetic variation has formed a foundation for DNA-based forensic applications. And, as attention is focused on locating genes underlying complex diseases, it is becoming clear that a better understanding of genetic variation will help to guide gene-mapping efforts. Population genomics, the large-scale comparison of DNA sequences, is now beginning to provide new insights in these areas. We review some of the general patterns of human genetic variation, and we show how our knowledge of these patterns can aid in the mapping and cloning of disease-causing genes.

Evolution, Molecular↗

A Dutch population study of the STR Loci HUMTHO1, HUMFES/FPS, HUMVWA31/1 and HUMF13A1, conducted for forensic purposes.

We report on a Dutch population study of the STR loci HUMTHO1, HUMFES/FPS, HUMVWA31/1, and HUMF13A1, in which we used multiplex amplification and automated fragment detection. Genotype and allele frequencies showed no deviation from Hardy-Weinberg and linkage equilibrium. The improved Bonferroni procedure was used to combine the results of several tests. The power of discrimination of a complete profile exceeded 0.9998. We compared the allele frequencies in the Dutch sample to the frequencies in other populations using a bipilot to visualize alleles and populations simultaneously. The Dutch sample was similar to most other Caucasian samples. The data demonstrate that the genetic systems in this report are a valuable tool for forensic identity testing in The Netherlands.

Ethnicity↗

[Genetic studies of 15 STR loci in Guangxi Miao population].

OBJECTIVE: The study was carried out to investigate genetic polymorphism of 15 STR loci in Guangxi Miao population. METHORDS: DNA samples from southern China 274 Miao unrelated individuals were screened by using AmpFlSTR Identifiler PCR Amplification Kit and 3100 Genetic Analyzer. RESULTS: These 15 loci meet the Hardy-Weinberg expectations. The matching probability of the 15 STR loci was 5.04 x 10(-17), and combined paternity of exclution was 0.9999993 in Guangxi Miao population. CONCLUSION: Our results showed Identifiler PCR Amplification systems of 15 STR loci were useful enough to forensic case work in Guangxi Miao population.

Alleles↗

Study on the haplotypes of MICA and MICB microsatellite and HLA-B locus in the Guangzhou Han population.

The purpose of this study was to investigate the genetic polymorphisms and haplotypes of microsatellite locus in exon 5 of the MICA gene and intron 1 of the MICB gene and human leukocyte antigen-B (HLA-B) gene based on 106 samples of the Guangzhou Han population through means of polymerase chain reaction and the fluorescent technique (6-FAM). The corresponding haplotype frequencies, linkage disequilibrium values and relative linkage disequilibrium values were estimated based on population data. The results show that the genotype distributions of MICA and MICB microsatellite and HLA-B satisfy the Hardy-Weinberg equilibrium. In total, five alleles of MICA microsatellite locus and 14 alleles of MICB microsatellite locus were observed. MICA A5 was the most common allele (0.2877), whereas A4 was the least common (0.1321). MICB CA14 was the most common allele (0.3255), and CA19 and CA28 were the two least common (0.0047). CA27 was not observed at all. Five kinds of MICA-MICB haplotypes, 18 kinds of MICA-HLA-B haplotypes and 12 kinds of MICB-HLA-B haplotypes occurred at frequencies of more than 1%. The common haplotypes of MICA-MICB, MICA-HLA-B and MICB-HLA-B were A5-CA14, A5.1-CA18, A4-CA26, A9-CA15, A5-B*15(62), A5.1-B*1301/1302, A4-B*1301/1302, A6-B*51, A6-B*4403, A9-B*3802, CA14-B*4601, CA18-B*1301/1302 and CA26-B*1301/1302, and these haplotypes showed strong linkage disequilibrium. The polymorphisms and haplotype distributions of MICA and MICB microsatellite and HLA-B locus in the Guangzhou Han population have their own distinct genetic characteristics. The microsatellite locus of exon 5 of the MICA gene and intron 1 of the MICB gene could therefore be used as genetic markers in the studies of anthropology, gene linkage analysis in genetic diseases, individual identification and paternity testing in forensic medicine.

Asian People↗

Testing and evaluation of 43 "noncore" Y chromosome markers for forensic casework applications.

A developmental validation study was performed on three Y-STR multiplex systems, Multiplex III (MPIII), Multiplex IV (MPIV), and Multiplex V (MPV), to ascertain their potential applicability to forensic casework. MPIII contains eight Y-STRs, including DYS426, DYS435, DYS436, DYS441, DYS442, DYS446, DYS462, and Y-GATA-A10, and one InDel, YAP (DYS287). MPIV contains 21 Y-STR loci, including DYS443, DYS444, DYS445, DYS447, DYS448, DYS449, DYS452, DYS453, DYS454, DYS455, DYS456, DYS458, DYS463, DYS464, DYS468, DYS484, DYS522, DYS527, DYS531 DYS557, and DYS588. MPV contains 13 Y-STR loci, including DYS459, DYS476, DYS488, DYS513, DYS549, DYS561, DYS570, DYS575, DYS576, DYS590, DYS594, DYS598, and DYS607. Full genetic profiles were consistently obtained for all three multiplexes with 25-50 pg of male DNA. No significant amplification was observed with 1 mug of female DNA. Each multiplex permitted the determination of the number of male donors in male:male DNA admixtures. Species specificity studies demonstrated some cross-reactivity with some primate samples. Environmentally compromised blood samples produced full or partial profiles after exposure to various conditions for up to 1 year. Full profiles were recovered from simulated casework specimens including cigarette butts and postcoital cervicovaginal swabs. Population data were collected to determine individual loci gene diversity and multiplex discriminatory capacity.

Animals↗

[The genetic polymorphism of 8 STR loci in northern Chinese Han and Uygur populations].

OBJECTIVE: The genetic polymorphism of 8 STR loci, was studied in northern Chinese Han and Uygur populations. METHODS: The 8STR loci(vWA,TH01, TP0X, CSF1P0, D5S818, D13S317, D7S820, D16S539) were analyzed and genotyped by fluorescent prime labeling kit and gene scan technology. RESULTS: 62 alleles were found in 100 individuals of Han population, CPE value was 0.9975; And 52 alleles were found in 50 individuals of Uygue population, CPE value was 0.9973. The TDP of both was beyond 0.9999. The difference of gene frequency between the two populations was significant. CONCLUSION: The genetic polymorphism of the 8 STR loci in the Han and Uygue populations is high, there are ethic differences in frequency distribution.

Alleles↗

Genetic variation in hemp and marijuana (Cannabis sativa L.) according to amplified fragment length polymorphisms.

Cannabis sativa L. (Cannabaceae) is one of the earliest known cultivated plants and is important in the global economy today as a licit and an illicit crop. Molecular markers distinguishing licit and illicit cultivars have forensic utility, but no direct comparison of hemp and marijuana amplified fragment length polymorphism (AFLP) has been made to date. Genetic variation was surveyed in three populations of fiber hemp and a potent cultivar of marijuana using AFLP markers. Ten primer pairs yielded 1206 bands, of which 88% were polymorphic. Eighteen bands represented fixed differences between all fiber populations and the drug cultivar. These markers have practical utility for (1) establishing conspiracy in the cultivation and distribution of marijuana, (2) identifying geographic sources of seized drugs, and (3) discriminating illegal, potent marijuana cultivars from hemp where the cultivation of industrial hemp is permitted.

Cannabis↗

Capillary electrophoresis of DNA for molecular diagnostics.

A number of applications of capillary zone electrophoresis (CZE) in sieving liquid polymers (notably linear polyacrylamides and cellulose) for the analysis of polymerase chain reaction (PCR) products of clinically relevant, diagnostic DNA, are reviewed. The fields covered are: human genetics, quantitative gene dosage, microbiology and virology, forensic medicine and therapeutic DNA (notably, antisense nucleotides). Some unique, novel developments are highlighted, such as: (i) nonisocratic CZE, i.e., temperature-programmed CZE for detection of DNA point mutations; (ii) the synthesis of novel N-substituted acrylamides, offering extreme resistance to alkaline hydrolysis coupled to high hydrophilicity. In the field of denaturing gradient gel electrophoresis (DGGE), as routinely performed in gel slabs, a novel methodology is described in CZE: double-gradient DGGE. In this technique, two gradients are simultaneously applied along the migration direction: a chemical (or thermal) denaturing gradient, for partially unwinding homo- and hetero-duplexes of DNA, and a porosity gradient, for recompacting diffuse bands melting over a broader range of denaturing conditions. It is thus demonstrated that chemical gradients, in addition to temperature gradients, can be easily implemented even in a capillary format.

Bacterial Infections↗

Instability of interstitial telomeric sequences in the human genome.

The length variability of four human interstitial telomeric sequences (ITs) is described. Three of the ITs contain short telomeric stretches ranging between 53 and 84 bp and are localized in 21q22, 2q31, and 7q36; the fourth IT derives from the subtelomeric domain of chromosome 6p and contains a tract of a few hundred basepairs of exact and degenerate repeats. Using primers flanking the repeats, we amplified the genomic DNA from unrelated individuals and from family members, and we found that all the loci are polymorphic. At the 21q22 IT locus, two equally frequent alleles were found, while the number of alleles at the 2q31, 7q36, and 6pter IT loci was 8, 6, and 4, respectively. Sequence analysis revealed that in the three loci containing short ITs the alleles differ from one another for multiples of the hexanucleotide; it is likely that the mechanism leading to the polymorphism is DNA polymerase slippage. These loci were also unstable in gastric tumor cells characterized by microsatellite instability. At the 6pter IT locus, the four alleles range in length from about 500 to about 700 bp; this variability is probably due to unequal exchange or gene conversion. Our data indicate that stretches of exact internal telomeric repeats can be highly unstable, like microsatellites with shorter units, and that they can be useful polymorphic markers for linkage analysis, for forensic applications, and for the detection of genetic instability in tumors.

Alleles↗

A study on the short tandem repeat system ACTBP2 (SE33) in an Austrian population sample.

Population genetic studies were carried out on 932 caucasians from Austria using the short tandem repeat system ACTBP2 (SEE33). A sequenced allelic ladder was used for typing (Möller et al. 1995). After native polyacrylamide gel electrophoresis all 26 alleles of the ladder were found as well as 194 alleles which migrated differently from those in the ladder. Forensically relevant parameters were calculated (discrimination power: 0.989, mean exclusion chance: 0.854, observed heterozygosity 0.946). An allele consisting of 9 repeats which is not part of the allelic ladder was also found. In 692 meioses 5 mutations were found (mutation rate 0.72%).

Actins↗

DNA profiling.

Although some concerns still remain in standard DNA profiling technology over the assumptions from population genetics used to calculate expected match frequencies, forensic scientists are preparing for the introduction of the next generation of DNA profiling techniques based on the polymerase chain reaction. These new techniques offer the prospect of dramatically increasing the speed and sensitivity of DNA profiling and have already been applied in some casework studies.

Base Sequence↗

Inherited Treacher-Collins syndrome in twins after artificial insemination.

We present two cases of the Treacher-Collins syndrome and one case of plagiocephalus in a trigeminus childbirth resulting from artificial insemination. The mother, although affected with the Treacher-Collins syndrome, was not diagnosed before the birth of her children. Genetic counseling did not occur. Medical and forensic problems resulting from modern techniques of reproduction are briefly discussed.

Adult↗