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At least 523 records · Page 29Linked to original sources
PubMed1990

Rapid diagnosis of Miller-Dieker syndrome and isolated lissencephaly sequence by the polymerase chain reaction.

Probe YNZ22 (D17S5) is a highly polymorphic, variable number tandem repeat (VNTR) marker previously shown to be deleted in all patients with the Miller-Dieker syndrome (MDS) but not in patients with isolated lissencephaly sequence (ILS). Primers were constructed to the unique sequence flanking the polymorphic, repetitive region of YNZ22 for amplification by the polymerase chain reaction (PCR). Analysis of 118 normal individuals revealed 12 alleles (differing in copy number of a 70-bp repeat unit) ranging in size from 168 to 938 bp. A retrospective study of eight MDS and six ILS patients was consistent with Southern blot analysis in all cases except one. In the latter, a very large allele (12 copies of the repeat unit) in a patient and her mother failed to amplify on initial attempts, but was successfully amplified by reducing the concentration of genomic DNA used in the reaction. Prospective studies on two MDS and five ILS patients were successfully performed and confirmed in all cases by Southern blot analysis. From the total sample, restriction fragment length polymorphism (RFLP) analysis was fully informative in four of ten MDS patients and showed a deletion in all four cases. Nine of eleven ILS patients were heterozygous and therefore not deleted for YNZ22. Development of primers for additional polymorphic markers in the Miller-Dieker region will lead to a rapid PCR-based diagnostic approach for all MDS and ILS patients. PCR typing of YNZ22 will also facilitate use of this marker in other applications, including genetic linkage, paternity and forensic studies, and analysis of loss of heterozygosity in tumors.

Abnormalities, Multiple↗
PubMed1996

Biological and clinical significance of haptoglobin polymorphism in humans.

Haptoglobin is a hemoglobin-binding protein expressed by a genetic polymorphism as three major phenotypes: 1-1, 2-1, and 2-2. Most attention has been paid to determining haptoglobin phenotype as a genetic fingerprint used in forensic medicine. More recently, several functional differences between haptoglobin phenotypes have been demonstrated that appear to have important biological and clinical consequences. Haptoglobin polymorphism is associated with the prevalence and clinical evolution of many inflammatory diseases, including infections, atherosclerosis, and autoimmune disorders. These effects are explained by a phenotype-dependent modulation of oxidative stress and prostaglandin synthesis. Recent evidence is growing that haptoglobin is involved in the immune response as well. The strong genetic pressure favoring the 2-2 phenotype suggests an important role of haptoglobin in human pathology.

Chemistry, Clinical↗
PubMed1994

[Applications of forensic DNA technology in Gynecologic practice].

Genetic characterization of biological material in criminal cases and for parentage testing at the DNA level has gained wide acceptance. This paper describes the basic methodology of restriction fragment length polymorphism (RFLP) and the methodology based on the polymerase chain reaction (PCR). RFLP typing is performed in all cases where larger quantities of DNA are available because of its high discrimination power. PCR is used when only limited quantities of DNA or degraded DNA are available. There is a lot of applicabilities for the gynecologist, primarily in the investigation of sexual assault cases and in parentage testing of newborns, which is shown by several examples of forensic cases.

Adult↗
PubMed2001

[A study of genetic polymorphism of the STR locus D2S441 in Chinese Han population in Chengdu].

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↗
PubMed2003

Molecular diagnostics in routine practice: quality issues and application to complex disease.

The public already has concerns about 'the new genetics', and it is clear that confidence can only be maintained by scrupulous attention to quality. Standards can be improved by harmonization of methods, discouraging poor practice and using appropriate internal and external quality controls. At present, despite the profound implications of genetic test results, few genetic tests are subject to sufficient scrutiny. The Human Genome Project will lead to the identification of numerous genetic variations contributing to multifactorial diseases, and high-throughput technologies will permit the generation of disease-susceptibility profiles. Clinical laboratories will need to develop the wherewithal to handle these data and present them in a format that is clinically useful.

Biotechnology↗
PubMed2006

Genetic variation of 13 STR loci in the four endogamous tribal populations of Eastern India.

We have analysed 13 autosomal STR loci in four endogamous tribal populations from two eastern states (Orissa and Nagaland) of India. The Gadaba, Kuvi Khond and Lotha Naga populations have not been analysed for microsatellite genetic variation previously. The allele frequencies for all loci are within the range observed in the geographical region and racial background, though some alleles showed greater variation. Departures from the Hardy-Weinberg equilibrium were tested by three methods and two loci (THO1 and TPOX) showed significant departures for all measures in Gadaba and Lotha Naga populations. The exclusion probability and discrimination probability were high for all analysed loci in all populations. There is no evidence for association of alleles among the STR loci studied. This allele frequency information will be useful for forensic, paternity and population genetic studies.

DNA Fingerprinting↗
PubMed1989

[DNA fingerprints and hypervariable regions: genetic marker with many application potentials in medicine and biology].

DNA polymorphisms are based on variations in the nucleotide sequences of the DNA within a given population and are transmitted from parents to offspring by Mendelian inheritance. Most of these mutations are phenotypically silent. Two different types of DNA polymorphisms are restriction fragment length polymorphisms and highly variable regions (HVRs), the latter with many different alleles at a given locus. Molecular probes for HVRs (or DNA minisatellites) can detect a great number of cross-hybridising fragments dispersed throughout the genome. The polymorphic patterns of these fragments are completely individual-specific, hence termed DNA "fingerprints". DNA "fingerprinting" has been shown to be a powerful tool for establishing family relationships, for example in paternity disputes, and for the positive identification of individuals in forensic medicine. The technique may be used to document marrow engraftment in patients who have undergone allogeneic bone marrow transplantation. DNA "fingerprinting" is a new method of assessing clonality in human tumours by identifying clonal somatic mutations in the tumour DNA. Cloning of individual DNA "fingerprint" fragments yields locus-specific HVR probes which, due to their high rate of heterozygosity, are ideal for linkage analysis and prenatal diagnosis in single gene disorders. This is exemplified by adult polycystic kidney disease, which has been found by a 3'alpha-globin-HVR probe to be closely linked to the alpha-globin-gene cluster on chromosome 16p. Locus-specific HVR probes have been used for the molecular diagnosis of clonal chromosomal deletions or loss of heterozygosity at particular loci in a large variety of tumours. These findings are the basis for the identification of anti-oncogenes or putative tumour-suppressor genes in the human genome.

Animals↗
PubMed1989

The polymerase chain reaction: an improved method for the analysis of nucleic acids.

The polymerase chain reaction (PCR) is a method for the selective amplification of DNA or RNA segments of up to 2 kilobase-pairs (kb) or more in length. Synthetic oligonucleotides flanking sequences of interest are used in repeated cycles of enzymatic primer extension in opposite and overlapping directions. The essential steps in each cycle are thermal denaturation of double-stranded target molecules, primer annealing to both strands and enzymatic synthesis of DNA. The use of the heat-stable DNA polymerase from the archebacterium Thermus aquaticus (Taq polymerase) makes the reaction amenable to automation. Since both strands of a given DNA segment are used as templates, the number of target sequences increases exponentially. The reaction is simple, fast and extremely sensitive. The DNA or RNA content of a single cell is sufficient to detect a specific sequence. This method greatly facilitates the diagnosis of mutations or sequence polymorphisms of various types in human genetics, and the detection of pathogenic components and conditions in the context of clinical research and diagnostics; it is also useful in simplifying complex analytical or synthetic protocols in basic molecular biology. This article describes the principles of the reaction and discusses the applications in different areas of biomedical research.

Base Sequence↗
PubMed1984

Human genetics and human rights. Identifying the families of kidnapped children.

Between 1975 and 1983 in Argentina, at least 145 children were kidnapped with their parents or born in captivity to imprisoned women and then separated from their mothers. The parents of these children generally remain among the missing persons. However, the grandparents of the kidnapping victims and the Argentinian government are concerned with identifying these children. Genetic analysis can aid in determining whether a child who may be among the kidnap victims is related biologically to a particular family. Laboratory analysis of genetic markers in human blood enables the calculation of an "index of grandpaternity." This index reflects the probability that a child shares genes with a specified set of grandparents because he is their grandchild compared to the probability he and they share similar genes only by chance. The most useful system for this analysis is HLA, although other genetic markers including blood groups, red cell enzymes, plasma proteins, and DNA polymorphisms can be tested to provide adequate information in families with only one or two living grandparents. This approach has been applied successfully in Argentina, with an index of grandpaternity for one family of 99.9%, based on HLA typing only.

Child↗
PubMed1998

Regional genetic variation in Caucasians.

When evaluating DNA evidence, the necessary calculations are often carried out using databases drawn from broad populations; for example, the Forensic Science Service (FSS) maintains genetic databases for the 3 major racial groups of England and Wales--Caucasian, Afro-Caribbean and Asian (from the Indian subcontinent). The resulting figures may be challenged in court on the premise that they are not based on data from the population of most relevance in the particular case under consideration. One important factor might be the location of the crime. Since the recent establishment of a National DNA Intelligence Database, data have been made available from a wide range of geographical regions in England and Wales. This paper gives details of analyses conducted to measure the differentiation between white caucasian populations from these regions and from other areas of the UK and abroad using a Bayesian approach.

Bayes Theorem↗
PubMed2000

Palaeogenetic analysis of (pre)historic artifacts and its significance for anthropology.

The possibility of isolating ancient DNA (aDNA) from all kinds of (pre)historic anthropogenetic artifacts opens new perspectives. This study applies palaeogenetic techniques to three anthropological issues: 1. Palaeodiet. DNA sequences from organic residues in vessels identify Precolumbian Aztec diet. 2. (Pre)historic husbandry and economic structures. aDNA data can reveal the species and the genetic evolutionary stage of animals and plants and show the manner and the extent of their growth, cultivation, or domestication. 3. Production techniques, use, and functionality. Identification of the plant or animal source of an archaeological find can reveal the use or the function of the find. Examples from a Celtic "sausage-end" and an Aztec "eye salve" are given.

Archaeology↗
PubMed1994

Likelihood ratios for DNA identification.

Likelihood ratio (LR) tests are provided for the three alternatives to DNA identity: exclusion, coincidence, and kinship. The coincidence test uses the radius of coalescence to conserve the observed frequency of single band phenotypes. Genotype probabilities under kinship are derived for mating groups, specified relatives, and structured populations; and unbiased estimates of the genetic parameters are provided. The LR is made robust to gene frequency errors by specifying the mean matching probability, and the tolerable loss of information this entails is determined by LR theory. This straightforward application of the seminal work of Jerzy Neyman and Sewall Wright strongly supports the use of LRs and kinship for presentation of DNA evidence by expert witnesses and committees.

Adult↗
PubMed2000

Motherless case in paternity testing.

In paternity test using the DNA evidence, the analysis of the deficient case that the DNA profiles of mother or alleged father are not available is different from that of the trio case analyzed routinely. However, the motherless case that the genotypes of mother is not available has been requested and analyzed like the trio case. In this paper, we compared the motherless case and the trio case through the mean exclusion chance describing the probability of exclusion for a genetic marker system and the distribution of the probability of paternity calculated using the three current methods. We have also shown a case which can be falsely discriminated if it were requested in the analysis of the motherless case, and conclude that the analysis of the motherless case should be carefully conducted and the level for the discrimination should be different from that of the trio case.

DNA Fingerprinting↗
PubMed2000

Analysis of genotype frequencies and interlocus association for the PM, DQA1, and D1S80 loci in four populations.

Allele frequencies of the LDLR, HBGG, GYPA, D7S8, GC, DQA1, and D1S80 loci are presented and genotypes are analyzed for each of four ethnic groups: African Americans (n = 200), US Caucasians (n = 200), US Hispanics (n = 200), and Japanese (n = 89). Hardy-Weinberg genotypic proportions were observed in all but two of the 28 population-locus tests undertaken. Those two instances are attributable to type I statistical error. Gametic equilibrium among loci is an assumption invoked for application of the product rule to utilize the discriminatory power from two or more loci simultaneously. Two statistical methods, a genotype matching statistic and log-linear modeling, were used to evaluate gametic disequilibrium. The match statistic, comparing observed to expected likelihood of genotypic identity for seven loci among pairs of individuals within the database, revealed only one statistically significant deviation among 20 tests. As expected, the probability of match was generally lowest in the test on all ethnic groups combined, indicating that allele frequencies differ among ethnic groups for some of the loci. This was confirmed with the statistic theta to measure ethnic stratification, in which about 0.10 of the genetic variation is apportioned among the four ethnic groups for four of the structural loci (LDLR, HBGG, GC, and DQA1), while for GYPA, D7S8, and D1S80, variation is more uniformly distributed among ethnic groups. Log-linear modeling was also applied to the five PM loci. The most parsimonious log-linear model included only three higher order terms: the two-way interactions of three of the PM loci with ethnic group. These three instances (LDLR, HBGG, and GC) indicated differences in allele frequencies between ethnic groups. No two or higher way interaction (disequilibrium) was observed among loci. In summary, the assumptions of Hardy-Weinberg and gametic equilibrium that facilitate the use of the five PM loci, DQA1 and D1S80 in forensic applications are consistent with the allele and genotype frequencies observed in these populations.

Asian People↗
PubMed1993

Kinship bioassay on hypervariable loci in blacks and Caucasians.

Four hypervariable loci were examined in DNA samples of American Blacks and Caucasians. Genetic diversity, measured by mean kinship within race, is 0.004 for a sliding window equal to twice the radius of coalescence of the autoradiographic bands. Kinship increases with the width of a window or bin, but it is an order of magnitude less than for blood groups and isozymes. This must reflect the greater mutability of hypervariable loci and absence of divergent selection. Low kinship implies that matching probabilities do not depend critically on race. Complete matching between pairs of loci shows deviations from independence, presumably because of inadvertent inclusion of replicated samples or related individuals. Multilocus matching probabilities were corrected for this (possibly spurious) dependence; the correction is negligible. When the complexities of coalescence, kinship, and dependent matching are allowed for, the probability calculations used in forensic identification are reliable. Recent counterarguments without theoretical basis or empirical support are discussed.

Black People↗
PubMedDate not supplied

[Genetic research as a means of proof in the German penal trial after the reform of the Court Rules of Procedure of 17 March 1997 (I)].

The authors reviews genetic fingerprinting practice and cases in Germany following the adoption of the new specific regulatory measures in the StPO, and looks at German case law on the subject. Also examined are the way in which the issue of human rights and some doubts which have arisen among authors and the courts have been resolved. The positive aspects of the new regulations are underlined and the author concludes with some proposals for application of these, lege ferenda, in Spain.

DNA Fingerprinting↗
PubMed2000

Allelic distribution of four tetranucleotide repeat loci (D3S1358, D18S51, D19S253, and FGA) in a population from Porto (North Portugal).

Allele frequencies for four short tandem repeat loci were determined in a population sample from Porto (North Portugal), using the polymerase chain reaction (PCR), in order to investigate possible genetic differences between populations from the center and north of Portugal. After denaturing PAGE electrophoresis, nine alleles were identified for D3S1358 (n = 256), 13 alleles for D18S51 (n = 235), 10 alleles for D19S253 (n = 238), and 15 alleles for FGA (n = 181). No deviations from Hardy-Weinberg equilibrium were found. The allele frequencies observed are similar to those of the Portuguese population compared except for the D3S1358 system.

Alleles↗