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[The polymorphism distributions of MICA and MICB microsatellite in Guangdong Han population].

OBJECTIVE: To investigate the genetic polymorphism of microsatellite in the exon 5 of MICA gene and the intron 1 of MICB gene in Guangdong Han population. METHODS: One hundred and six samples of Guangdong Han population were genotyped by polymerase chain reaction and fluorescent technique (6-FAM). Gene frequency, power of discrimination, expected heterozygosity, polymorphism information content and probability of paternity exclusion were calculated. RESULTS: The genotype distributions of MICA and MICB microsatellite met Hardy-Weinberg equilibrium. MICA A5 was the most common allele (0.2877), whereas A4 was the least popular one (0.1321). The genotype distribution frequencies of A5-5.1 (14.15%) and A5-5 (10.38%) are high. MICB CA14 was the most common allele (0.3255), and CA19,28 was the least popular one (0.0047). CA27 was not observed. The genotype distribution frequency of CA14-CA14(14.15%) is high. CONCLUSION: The microsatellite of the exon 5 of MICA gene and the intron 1 of MICB gene could be used as the genetic markers of Chinese population in the studies of anthropology, linkage analysis of genetic disease genes, individual identification and paternity test in forensic medicine.

China↗

[Haplotypes of DXS10011 and DXS8377 in Guangdong Han individuals].

OBJECTIVE: To investigate genetic polymorphism of two X chromosome specific STR: DXS10011 and DXS8377 in male samples from Guangdong Han population. METHODS: The DNA samples were amplified by PCR and analyzed by polyacrylamide gel electrophoresis followed by silver staining. RESULTS: Among 113 samples, 20 alleles were found for DXS1011 and 12 alleles for DXS8377. Also, 72 DXS10011-DXS8377 haplotypes were shown. The most common haplotypes only occurred three times. When only female children were tested in motherless case, the exclusion probability of paternity was 0.9588 for DXS10011-DXS8377 haplotypes. Investigations in 83 family trios with female children and 29 pedigrees with two children suggested a co-dominant X-linked inheritance; mutations were not found. CONCLUSION: Our data indicate that DXS10011 and DXS8377 are highly informative X chromosome markers for complicated kinship analysis.

Alleles↗

Genetic diversity and relationships among the tribes of Meghalaya compared to other Indian and Continental populations.

The autosomal AmpFLSTR markers validated and widely used for forensic applications are used in this study to examine the extent of diversity and genetic relationships among nine Meghalaya populations. Altogether, 932 chromosomes from 9 populations were analyzed using 9 tetrameric AmpFLSTR loci. The included populations were all seven subtribes of the Austro-Asiatic Mon-Khmer-speaking Khasi and the neighboring Tibeto-Burman Garo. The Lyngngam, which are linguistically closer to the Khasi but are culturally intermediate between the Khasi and the Garo, are also included in the study. Although most of the microsatellite loci are highly polymorphic in each of these populations, the allele distributions are fairly uniform across the Meghalaya populations, suggesting relative homogeneity among them. Concurrent with this, the coefficient of gene differentiation (G(ST)) is observed to be low (0.026+/-0.002). This is naturally reflected in the lack of clear differentiation and clustering pattern of the Meghalaya tribes based on either geographic proximity or the historical or current affiliations of these tribes. Analysis of molecular variance (AMOVA) suggests no significant population structure. The structure analysis further suggests that, barring War-Khasi and Pnar, no other population shows any semblance of genetic identity. Even the position of the linguistically distinct Garo is not portrayed as separate from the Khasi. However, when comparable data from other Indian, Southeast Asian, and other continental populations were analyzed, the Meghalaya populations formed a compact cluster clearly separated from other populations, suggesting genetic identity of the Meghalaya populations as a whole. These results are concurrent with the hypothesis of a common and recent origin of these Meghalaya populations, whose genetic differentiation is overwhelmed by the homogenizing effect of continuous gene flow.

Alleles↗

Evidence in support of self-declaration as a sampling method for the formation of sub-population DNA databases.

Well constructed sub-population databases are fundamental to the application of DNA-based forensic statistics. The size of such databases can affect the ability to examine adequately statistical or population genetic features, and the integrity of both the DNA profile and associated ethnicity information is also of importance. Use of short tandem repeat (STR) DNA profiling technology and the thoughtful construction of the governing legislation has seen large databases of DNA profiles collated for the four major sub-populations of New Zealand. Examination of the data illustrates the suitability of self-declaration as a means of categorizing samples on the basis of ethnicity.

Databases as Topic↗

[Heteroplasmy in human mtDNA control region].

OBJECTIVE: To observe the length heteroplasmy and point heteroplasmy in human mtDNA control region. METHODS: The peripheral blood, buccal cell, and single hair shaft from 50 individuals and 16 family members, related in their maternallineage were analyzed by direct sequencing, and clones from 20 individuals whose mtDNA sequences have a T-C transition at 16189 nt were sequenced. RESULTS: No point heteroplasmy were observed in peripheral blood, buccal cell, single hair shaft from the same individual, neither in maternally related individuals. Length heteroplasmy was observed in those individuals with a homopolymeric tract and the different clones from the same individual has different proportions of length variants, but the hair shafts from the same individual were very similar to the measurements made from blood DNA. No length heteroplasmy was observed between different tissues from the same individual. CONCLUSION: mtDNA sequences have a characteristic of high consistency and genetic stability, mtDNA sequencing is a suitable tool for forensic applications such as individual identification.

Base Sequence↗

[Genetic factor in reactive psychoses (concerning their possible hereditary heterogeneity)].

The authors analyzed clinical and genealogical findings about the psychopathological aggravation of heredity in patients with reactive psychoses. The data were collected by studying a familial history in an epidemiological forensic-psychiatric sample of psychogenic psychoses. A conclusion is made about genetic heterogeneity of psychogenic paranoids and psychogenic depressions as well as hysterical and endoformic psychogenic psychoses on the whole.

Adult↗

Variation at three short tandem repeat (STR) loci in Australians: forensic and ethnic considerations.

We report the results of typing three short tandem repeat (STR) polymorphisms by a multiplex system in three forensically relevant populations of Australia; (i) a general Australian, (ii) a Caucasian, and (iii) an Asian sample. The STRs are tetranucleotide repeats in the following autosomal genes; CSF1PO, TPOX and THO1, and collectively comprise the CTT multiplex (Promega). In all three population samples, each of the loci exhibited genotype frequencies consistent with those expected under Hardy-Weinberg equilibrium, and, further, there was no significant deviation from random association of alleles across separate loci. These two characteristics, plus the high discrimination power values, demonstrate that the CTT multiplex system is a powerful tool for DNA profiling in Australian jurisdictions. Australian Asians and Caucasians exhibit frequencies of alleles at these three STR loci very similar to those in other Asian and Caucasian samples. While most of the variation exists within any single population, there are still considerable differences between Asians and Caucasians. This difference between the two groups is minimal with respect to TPOX and greatest for THO1 alleles.

Alleles↗

Mitochondrial D-loop 3' (CA)n repeat polymorphism: optimization of analysis and population data.

We report a dinucleotide repeat polymorphism in the 3' area of the mitochondrial control region. The fragments obtained using a new primer set could be reliably separated by polyacrylamide gel electrophoresis (PAGE) using nondenaturing gels. A total of five alleles [(CA)3 to (CA)7] were detected on silver-stained gels. The 90 bp product corresponds to allele 5. Samples from one African and three European populations were characterized. Significant differences could be demonstrated as to the incidence of single alleles and allele distributions in different populations. These differences were found between the three European and one African Bantu population. For specific forensic questions the mitochondrial CA repeat is well suited. Gene diversities in populations of Germany, Hungary, the Russian Federation and Cameroon were 0.36, 0.40, 0.34, 0.52, respectively.

Africa↗

Forensic DNA typing by the solid-phase minisequencing method.

We describe a method for DNA-typing, in which a panel of biallelic markers are detected by the solid-phase minisequencing method (Syvänen et al., 1990). This method identifies single nucleotide variations in DNA fragments amplified by the PCR. Determination of the panel of 12 markers selected in this study proved to be an efficient and reliable method for forensic identification of individuals. We also introduce a novel approach for rapid determination of allele frequencies by quantitative analysis of pooled DNA samples.

Alleles↗

Swiss population data and forensic efficiency values on 3 tetrameric short tandem repeat loci-HUMTH01, TPOX, and CSF1PO-derived using a STR multiplex system.

Allele and genotype frequencies for 3 tetrameric short tandem repeat loci were determined in a Swiss population sample (n = 100) using the GenePrint STR Multiplex System, electrophoresis of the PCR products in DNA sequencing gels and subsequent detection of allelic fragments by silver staining. The loci are HUMTH01, TPOX, and CSF1PO. The observed heterozygosities are 83.0%, 60.0%, and 72.0%, respectively. The discrimination power determined for the individual loci is 0.914, 0.780, and 0.860, respectively, and the combined discrimination power for the triplex is 0.997. All loci meet Hardy-Weinberg expectations and after Bonferroni correction there was no evidence that the population sample deviates from expectations of independence. Moreover, independence of alleles at these STR loci with other PCR-based loci derived from the same Swiss population sample, previously reported, were considered. These loci were DQA1, LDLR, GYPA, HBGG, D7S8, GC and D1S80. Again, after Bonferroni correction there was no evidence that the population sample deviates from expectations of independence among alleles at the 10 different PCR-based loci. Thus, the allelic frequency data can be used in human identity testing to estimate the frequency of a multiple PCR-based DNA profile in the Swiss population.

Alleles↗

DNA single locus profiles: tests for the robustness of statistical procedures within the context of forensic science.

We describe a series of experiments, carried out on data from DNA profiles, which have been designed specifically to test the validity of the statistical procedures currently used in the Home Office Forensic Science Service. The tests address issues which have been the subject of topical debate, in particular those of representativeness and band independence. The results confirm the confidence which had already been placed in the established procedures. We recommend that all practitioners in the forensic field should carry out similar testing on their own data collections.

DNA Fingerprinting↗

A concordance of nucleotide substitutions in the first and second hypervariable segments of the human mtDNA control region.

A new and easily accessible concordance of nucleotide substitutions in the hypervariable segments of the human mitochondrial DNA (mtDNA) control region has been constructed. The concordance indexes all population-specific mtDNA sequences in a standardized format. The first edition of the concordance includes 1,440 sequences representing 762 mtDNA types from over 65 populations for hypervariable region 1, and 520 sequences representing 260 mtDNA types from over 26 populations for hypervariable region 2. Investigators are invited to submit new sequences to the database, and details for doing so are given in the text.

Anthropology↗

Experience with the PCR-based HLA-DQ alpha DNA typing system in routine forensic casework.

The results of HLA-DQ alpha typing from 42 routine forensic cases using the polymerase chain reaction (PCR) were analyzed regarding the reliability, discrimination efficiency and informative value of this system in a given case. The cases included stain typing from a variety of different substates, i.e. blood and semen stains, mixed body fluids, single hairs, cigarette butts, material from fingernail scratches, as well as identification and paternity cases on postmortem and fixed tissue. A total of 125 individual stain and tissue samples were included. PCR amplification was achieved in 70% of these samples. In cases with mixed body fluids, e.g. sperm and vaginal cells from rape cases, DQ alpha typing was always carried out successfully. However, only approx. 42% of all samples that could be typed were relevant regarding the inclusion or exclusion of a suspect. This was mostly due to the limited number of alleles that can be typed at the HLA-DQ alpha locus or to the fact that the stain or hair samples did not originate from the perpetrator, but from the victim or from other persons not related to the crime.

DNA↗

pMCT 118 (D1S80): a new allelic ladder and an improved electrophoretic separation lead to the demonstration of 28 alleles.

Population data studies carried out on caucasians from Northwest Germany (n = 218) using the AMPFLP system pMCT 118 (D1S80). The method used in a previous study (Rand et al. 1992) for pMCT 118 could be improved by increasing the electrophoretic separation length from 10 to 20 cm and by using an extended allelic ladder which allowed the distinction of 8 additional alleles (a total of 28 alleles). Out of the 8 additional alleles 5 could be differentiated which differed within the 16 bp repeat sequence. The allele frequencies found were compared to population data from American caucasians, Hispanics and black Americans (Eisenberg and Maha 1991). All populations with the exception or black Americans, showed good agreement.

Alleles↗

D1S1171: a new highly variable short tandem repeat polymorphism.

This study reports the evaluation of the STR locus D1S1171 (GDB: 312934) for forensic purposes, which was investigated by PCR amplification and native polyacrylamide gel electrophoresis in 141 unrelated Austrians. No deviations from Hardy-Weinberg expectations were observed. The mean exclusion chance (MEC) was 0.677, the discriminating power (DP) was 0.951 and the observed heterozygosity rate was 0.853. An allelic ladder consisting of 10 sequenced alleles (96-132 bp) was constructed. Sequence analysis revealed a GAAA repeat motif. According to the number of tetranucleotide repeats the smallest allele was designated 9 and the largest allele 18.

Alleles↗

Forensic evaluation and population data on the new Y-STRs DYS434, DYS437, DYS438, DYS439 and GATA A10.

The Y-specific STR loci DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS434, DYS437, DYS438, DYS439 and GATA A10 were studied in a northern Portuguese population. Haplotype and allele frequencies of these 14 Y-chromosome STRs were estimated. In a sample of 212 individuals it was possible to define 196 different haplotypes of which 182 were found only once, 12 were found in 2 samples and the 2 most frequent haplotypes were shared by only 3 individuals. The observed haplotype diversity value was 0.9992. The usefulness of the inclusion of each of these new markers for forensic purposes is discussed by comparing expected and observed increases in haplotype diversity. When combining the new markers (DYS434, DYS437, DYS438, DYS439 and GATA A10) with the classical set (DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392 and DYS393) a 0.68% increase in haplotype diversity was obtained and the number of different haplotypes rose from 157 to 196. When DYS434 was not considered the haplotype diversity was not affected.

Forensic Medicine↗