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PubMed2003

What is the magnitude of the subpopulation effect?

The effect of population subdivision on estimated match probabilities has been raised [Nature 339 (1989) 501; Am. J. Hum. Genet. 48 (1991) 819; Science 254 (1991) 1921]. Previous work [J. Forensic Sci. 39 (1994) 319; J. Forensic Sci. 39 (1994) 988; Am. J. Hum. Genet. 55 (1994) 533] has compared product rule estimates from differing databases and found that the "subpopulation" error may be of the order of a factor of 10. This approach compares an estimate with an estimate. This paper uses simulation to extend these studies by allowing a comparison to a 'true match probability' and supports the conclusion that subpopulation effects are mild. In addition the performance of recommendations 4.1 and 4.2 of NRC II [National Research Council and C.O.D.F. Science, The Evaluation of Forensic DNA Evidence, National Academy Press, Washington, DC, 1996].

Consanguinity↗
PubMed1995

D1S80 VNTR locus genotypes in population of south Poland; meta-analysis pointer to genetic disequilibrium of human populations.

A highly variable number of tandem repeats (VNTRs) in a human locus D1S80 can prove to be useful for forensic science purposes. As with other genetic polymorphisms, a database of a local population allelic frequencies is needed to ensure that no departure from genetic equilibrium exists. DNA from the locus D1S80 was amplified by polymerase chain reaction (PCR) and analyzed by horizontal PAGE followed by silver staining. Samples from 133 unrelated inhabitants of Southern Poland were examined. The amplified fragment length polymorphism (AMP-FLP) analysis of the D1S80 locus demonstrated 21 alleles and heterozygosity of 0.85%. Out of the 231 possible genotypes, 47 were observed. The results were compared to the published D1S80 population studies and a meta-analysis of the genotype frequencies was performed. The G statistics revealed a deviation from genetic equilibrium in the Spanish population. Replicated goodness of fit tests showed highly significant heterogeneity of genotype distribution between tested populations. Therefore, interpretation of the casework on the basis of D1S80 locus typing may be biased by interpopulation differences.

Adult↗
PubMed2000

Genetics of the complement system.

After a brief history of complement genetics, general considerations and applications to our understanding of immune function, evolution, population structure and migration and forensic medicine, selected topics in complement genetics are presented. For individual complement proteins, genetic polymorphisms and deficiency states are described, as are the molecular bases of some of them. The clinical abnormalities exhibited by some patients with complement deficiency states are discussed, as are possible pathophysiologic mechanisms for them. The chromosomal location and the close linkage and a sharing of structural features by groups of complement proteins, such as the complotypes of the major histocompatibility complex, the regulators of complement activation, Clr and Cls, and the terminal components C6, C7 and C9, are presented in some detail. From these facts, the broad outlines are drawn of the evolution of the classical and alternative complement pathways from the lectin pathway and the terminal pathway from a common progenitor. From markers within the complotype region, rough conclusions are delineated regarding the evolution of C2, factor B, C4A and C4B alleles.

Animals↗
PubMed2002

Evaluation of factors affecting individual assignment precision using microsatellite data from horse breeds and simulated breed crosses.

Assignment tests have been utilized to investigate population classification, measure genetic diversity and to solve forensic questions. Using microsatellite data from 26 loci genotyped in eight horse breeds we examined how population differentiation, number of scored loci, number of scored animals per breed and loci variability affected individual assignment precision applying log likelihood methods. We found that both genetic differentiation and number of scored loci were highly important for recognizing the breed of origin. When comparing two and two breeds, a proportion of 95% of the most differentiated breeds (0.200 < or = FST < or = 0.259) could be identified scoring only three loci, while the corresponding number was six for the least differentiated breeds (0.080 < or = FST < or = 0.139). An identical proportion of simulated breed crosses, differentiated from their parental breeds by FST estimates in the range 0.050-0.069, was identified when scoring 12 loci. This level of source identification was not obtained for the less differentiated breed crosses. The current data further suggested that population sample size and locus variability were not critical for the assignment precision as long as moderately large sample sizes (> or = 20 animals per population) and fairly variable loci were used.

Animals↗
PubMed2006

[Polymorphisms of eleven Y-chromosome STR loci and forensic application in Yunnan Han population].

OBJECTIVE: To abtain the genetic polymorphisms data of eleven Y-chromosome STR loci in Yunnan Han population, and to evaluate its forensic application values, which will provide the base data for forensic application. METHODS: DYS391, DYS389 I, DYS439, DYS389 II, DYS438, DYS437, DYS19, DYS392, DYS393, DYS390 and DYS385a/b loci were amplified by using Powerplex Y PCR amplification Kit and were analyzed by 310 genetic analyzer. 201 unrelated male individuals of Han population in Yunnan were investigated to determine the distributions of allele frequencies and haplotypes. RESULTS: 3, 5, 6, 8, 5, 4, 5, 8, 4, 7 alleles were found across the Y-STR loci except DYS38556 haplotypes were found across DYS385a/b locus. The minimum GD value was 0.4273 (DYS438), and the maximum was 0.9747 (DYS385a/b). 175 haplotypes were found, of which 154 were unique, 16 were found in 2 individuals, 5 were found in 3 individuals, and the observed haplotypes diversity value was 0.9984. CONCLUSION: The 11 Y-STR loci are highly polymorphic and are suitable for forensic personal identification and paternity testing in Yunnan Han population.

Alleles↗
PubMed2006

Diagnosis of ectopic tissue versus contamination by genetic fingerprinting in a routine surgical pathology specimen.

A 62-year-old woman presented with recurring right upper quadrant pain and underwent a routine laparoscopic cholecystectomy. A large gallstone was found impacted in the fundus of the gall bladder. Interestingly, aside from noting mild inflammation of the gall bladder wall, microscopic examination of the specimen identified 2 fragments of benign thyroid tissue. Given the routine nature of the surgical procedure and lack of abnormality detected during the operation, the attending pathologist suspected extraneous tissue contamination ("floater") of the pathology specimen and submitted the block and slides to Molecular Pathology. The thyroid tissue-containing fragments and gallbladder wall were independently isolated and subjected to genetic fingerprinting using a standard forensic DNA identification panel. All fragments showed the identical fingerprint, strongly suggesting that they belonged to the same patient. The results indicated that the thyroid tissue was from an ectopic rest adjacent to the gall bladder, which has been reported only very rarely in the previous literature and illustrates the unusual use of molecular genetic testing to confirm the presence of ectopic tissue versus contamination.

Choristoma↗
PubMed2003

[HLA gene polymorphism and forensic medicine].

The gene complex of Human Leukocyte Antigen (HLA) is located of chromosome 6p21, which is the most complicated dominant polymorphic genetic system. The HLA system has 108 genotypes. It is the best human genetic marker. It has been applied to forensic paternity test and individual identification. This article discusses the research development of HLA polymorphism and its application in forensic medicine.

Forensic Medicine↗
PubMed2005

Allele distribution of five X-chromosome short tandem repeat loci in Ewenke population of north China.

OBJECTIVE: To study the allele genetic polymorphism of five short tandem repeat (STR) loci on X-chromosome in Ewenke population of north China and to provide basic data for forensic identification. METHODS: Genomic DNA was extracted from EDTA-whole blood of Ewenke population by Chelex-100. The DNA samples were amplified by PCR and were analyzed by polyacrylamide gel electrophoresis and silver staining. The sequence length variations of DXS6799, DXS8378, DXS101, HPRTB, and DXS6789 loci on X-chromosome in 98 unrelated Ewenke individuals were investigated. RESULTS: All five loci analyzed showed high polymorphism and genetic stability. The data of the five X-chromosome STR loci in Ewenke ethnic group of China was in accordance with Hardy-Weinberg equilibrium by Chi-square test. CONCLUSION: Allele polymorphism of five X-chromosome STR loci can be used as a genetic marker for forensic identification and population genetic research.

Asian People↗
PubMed2003

Genetic analysis of a Sicilian population using 15 short tandem repeats.

The genetic structure of the population of Alia (Sicily, Italy) was analyzed using 15 short tandem repeats: TPOX, D2S1338, D3S1358, FIBRA, D5S818, CSF1PO, D7S820, D8S1179, TH01, VWA, D13S317, D16S539, D18S51, D19S433, and D21S11. Two of these markers, D2S1338 and D19S433, have never before been used in research on population genetics and only recently have they been put to use in forensic medicine. Results of the analysis underline the genetic isolation of the Alia population and show it to be a recent bottleneck as a consequence of a cholera epidemic in 1837. While comparing the Alia population with other populations from Sicily, a genetic heterogeneity within Sicily was uncovered, thus confirming previous results obtained from the analysis of classical markers. This heterogeneity underlines the existence of genetic boundaries within the island. Comparisons with other Italian, Mediterranean, and European populations highlight the differentiation of the Sicilian population, reflecting the presence of a genetic boundary that separates Sicily from northern and central Italy and from the western Mediterranean basin.

Adult↗
PubMed2001

Analysis of microsatellite polymorphism in red deer, roe deer, and fallow deer -- possible employment in forensic applications.

DNA microsatellites play a major role in population genetics, linkage mapping, and parentage studies of mammals. In addition, they may be used for forensic purposes, if an individual identification of a specific animal is necessary. Therefore, we tested a variety of microsatellite polymorphism derived from reindeer (Rangifer tarandus) by PCR and sequencing analysis for use in red deer (Cervus elaphus), roe deer (Capreolus capreolus) and fallow deer (Dama dama). Twelve of these microsatellites were selected for further analysis. In all these microsatellite polymorphism short tandem repeats could be detected for one or all three species as shown by sequencing analysis. In red deer, more than two alleles were found in eight microsatellites, in roe deer more than two alleles could be demonstrated in seven microsatellites, whereas in fallow deer more than two alleles were found in only two microsatellite polymorphism. A comparison of sequences of PCR products from the three deer species with the sequences of reindeer revealed several differences between the four species. In six microsatellites -- selected because or their reliability in PCR and because of their polymorphic character -- we established a sequenced allelic ladder and give population data of all three species from 82 deer of the Northeast region of Germany (Vorpommern). Our results show the possibility to use microsatellite polymorphism in the identification of deer in forensic applications like poaching.

Alleles↗
PubMed1992

Polymerase chain reaction (PCR) amplification and human leukocyte antigen (HLA)-DQ alpha oligonucleotide typing on biological evidence samples: casework experience.

The polymerase chain reaction (PCR) method of specific gene amplification was used in casework to synthesize millions of copies of the polymorphic second exon of the human leukocyte antigen (HLA)-DQ alpha (or DQA1) locus from a variety of evidence samples. The HLA-DQ alpha allelic variants in the amplified deoxyribonucleic acid (DNA) were determined in a rapid non-radioactive test by hybridization to sequence-specific oligonucleotide probes in both the dot-blot and reverse dot-blot formats. This genetic typing system has been subjected to blind proficiency testing; the performance of this test in the analysis of experimentally mixed samples was also evaluated. As of August 1990, over 250 cases have been tested and more than 2000 individual evidence (bloodstains, semen stains, individual hairs, bone fragments, and tissue sections) and reference samples have been analyzed. The first 198 of these cases are summarized in this paper; in 65% of the cases with conclusive results a suspect was included, and in 35%, all suspects were excluded. Individual cases as well as some of the general issues relating to forensic science analysis and this genetic typing system are discussed. The high rate of exclusion reported here combined with the ability of PCR to type old evidence samples suggests the relevance of this genetic test for postconviction review; two cases in which the convicted suspect was excluded are discussed.

Adolescent↗
PubMedDate not supplied

Identification of blood stains by non-genetic characteristics: the HBs antigen of viral hepatitis B.

In forensic cases, until recently, identification of biological stains was based on the use of genetic markers, such as blood groups. In this paper, we show that another acquired characteristic, even if not immutable during life, may afford similar possibilities. As an example, we have demonstrated that the HBs antigen, associated with the hepatitis B virus, can help in the identification of bloodstains. The requisite condition for using this new marker, is that not too much time should elapse between the time the biological stains are formed and the moment when victim and suspected individual are examined for comparison of their blood with the stain. We have shown that in a dried state, the HBs antigen is very stable for a least six months. In vivo, it persists for a few week to 6 or 7 years according to thecase. HBs antigen is a relatively rate factor, its frequency being 0.5%ew marker, is that not too much time should elapse between the time the biological stains are formed and the moment when victim and suspected individual are examined for comparison of their blood with the stain. We have shown that in a dried state the, HBs antigen is very stable for a least six months. In vivo, it persists for a few week to 6 or 7 years according to the case. HBs antigen is a relatively rate factor its frequency being 0.5% in the Belgian population; the frequency reaches 2 to 3% in the Mediterranean population who constitute most of the immigrants in Belgium.

Blood Stains↗
PubMed2000

Alu elements and the human genome.

Alu insertional elements, the most abundant class of SINEs in humans are dimeric sequences approximately 300 bp in length derived from the 7SL RNA gene. These sequences contain a bipartite RNA pol III promoter, a central poly A tract, a 3' poly A tail, numerous CpG islands and are bracketed by short direct repeats. An estimated 500,000 to 1 x 10(6) units are dispersed throughout the human haploid genome primarily in AT rich neighborhoods located within larger GC dense chromosomal regions via a mechanism known as retroposition. Retroposition activity of Alu elements is determined by both internal and flanking regulatory elements as well as distant genes affecting transcription or transcript stability. Alu elements impact the organization and expression of the human genome at many levels including the processes of recombination, transcription and translation. Twelve subfamilies of Alu are defined by distinct patterns of diagnostic base substitutions. Subfamilies may be classified as young, intermediate or old reflecting the time since the start of retroposition by their members. Some insertions of the youngest subfamilies are not yet fixed in the human species and represent polymorphic loci. Alus are excellent molecular markers for a variety of reasons. They aid in tracing the complex pattern of duplication and rearrangements that occurred during the evolution of primate genome. Unlike other mutations, Alu sequences are rarely lost completely once retroposed, have a defined ancestral state and are free from homoplasy since independent and identical insertions are highly unlikely. Because of these characteristics, Alus are literally molecular fossils. Polymorphic Alu loci are especially useful in studies of human genetic diversity and in pedigree and forensic analysis.

Alu Elements↗
PubMed2006

Minisequencing-based genotyping of Duffy and ABO blood groups for forensic purposes.

Duffy and ABO blood group genetic polymorphisms were studied by minisequencing analysis of single-nucleotide polymorphisms (SNPs) at nucleotide positions--33, 125, 265, and 298 of the Duffy gene and at nucleotide positions-261, 297, 467, 646, and 703 of the ABO gene. In an Italian population sample, we found four alleles and seven genotypes for the Duffy and six alleles and 16 genotypes for the ABO systems. The lower limit for reproducible results was 200 pg DNA, with a range of up to 10 ng and an optimum at 1 ng. All of the 16 analyzed inclusive paternity tests were also consistent with parentage and two out of four inconsistencies with parentage cases were excluded by one or more SNPs. Although Duffy and ABO SNP typing show lower informativeness than most current forensic tests, their robustness, the limited population distribution of FY* Fy type, and the sensitivity of the minisequencing technology suggest that these markers can be useful in selected forensic applications.

ABO Blood-Group System↗
PubMed1996

VNTR locus D1S80: allele frequencies and genotype distribution in the region of Düsseldorf.

Hypervariable loci within the human genome are useful tools in several disciplines: for example in forensic medicine (paternity testing and forensic identification). One of these genetical markers is located at chromosome 1 and is called D1S80 (MCT118). The genotype distribution and the allele frequency of the VNTR locus D1S80 have been studied in a population of 378 unrelated Germans living at Düsseldorf. The determination of genotypes has been carried out by using the polymerase chain reaction and subsequent analysis of the amplified products by polyacrylamide electrophoresis followed by silver staining. The data demonstrate that the locus is highly polymorphic with an observed heterozygosity of 75.66%. The frequency distribution found does not meet Hardy-Weinberg expectations. We think that this is not astonishing because we found only 80 of the possible 231 phenotypes (alleles 16-34, 36-37, without anodal and cathodal variants). So before using the D1S80 data in forensic analyses and paternity tests a larger data base has to be established. The data of the Düsseldorf sample are compared with data of studies on other populations.

Alleles↗
PubMed2004

Mitochondrial DNA control region sequences from Nairobi (Kenya): inferring phylogenetic parameters for the establishment of a forensic database.

Large forensic mtDNA databases which adhere to strict guidelines for generation and maintenance, are not available for many populations outside of the United States and western Europe. We have established a high quality mtDNA control region sequence database for urban Nairobi as both a reference database for forensic investigations, and as a tool to examine the genetic variation of Kenyan sequences in the context of known African variation. The Nairobi sequences exhibited high variation and a low random match probability, indicating utility for forensic testing. Haplogroup identification and frequencies were compared with those reported from other published studies on African, or African-origin populations from Mozambique, Sierra Leone, and the United States, and suggest significant differences in the mtDNA compositions of the various populations. The quality of the sequence data in our study was investigated and supported using phylogenetic measures. Our data demonstrate the diversity and distinctiveness of African populations, and underline the importance of establishing additional forensic mtDNA databases of indigenous African populations.

Black People↗
PubMed2003

[Genetic polymorphisms of short tandem repeats loci F13A01, FESFPS, vWA from Han population in Guizhou].

OBJECTIVE: To understand the allele structure and genetic polymorphism at F13A01, FESFPS and vWA short tandem repeats (STRs) loci for Han population in Guizhou province of China, and to construct a preliminary database. METHODS: One hundred sixty unrelated individuals in Han population from Guizhou were analyzed by multiplex polymerase chain reaction. The resultant allele frequencies were compared with those of other population or race database. RESULTS: The genotype distributions of F13A01, FESFPS and vWA were in accordance with Hardy-Weinberg equilibrium. The combined discrimination power and polymorphism information content were 0.9984 and 0.9700 respectively. CONCLUSION: All of the three loci in this study provide useful markers for forensic paternity test and for genetic purposes.

Alleles↗