上海地区汉族人5-HT2a受体基因T102C多态性的基因频率分布

为了揭示中国汉族人5-HT2a受体基因T102C多态性基因频率的分布,我们随机抽取了226例汉族健康人作研究,用限制性片段长度多态性(RFLPs)技术测定研究对象的基因型和等位基因。结果发现汉族正常人5-HT2a受体基因T102C多态性基因型频率依次为:A1/A2=0.5044,A1/A1=0.2965,A2/A2 =0.1991,两种等位基因频率依次为:A1=0.5487,A2=0.4513,杂合度H=0.50 44、期望杂合度h=0.4953,多态信息量PIC=0.3726,表明T102C多态性具有合适信息,对疾病的关联研究,法医学鉴定有一定的价值。 Abstract:To investigate the distribution about genotype and allele frequencies of T102C polymorphism in the 5-HT2a receptor gene Chinese Han population,the genotypes and alleles of 226 healthy person were examined with Restriction Fragment Length Polymorphisms(RFLPs)technique.The genotype frequencies are as follows:A1/A2=0.5044,A1/A1=0.2965,A2/A2=0.1991,respectively,and the allele frequencies are as follows:A1=0.5487,A2=0.4513,respectively.The heterozygosity(H)is 0.5044,the expected heterozygosity(h)is 0.4953,and the Polymorphism Information Content(PIC)is 0.3726.Our findings suggest that the T102C polymorphism in 5-HT2a receptor gene may have suitable information to be used for association study or forensic identification.     

Sample size requirements for addressing the population genetic issues of forensic use of DNA typing.

DNA typing offers a unique opportunity to identify individuals for medical and forensic purposes. Probabilistic inference regarding the chance occurrence of a match between the DNA type of an evidentiary sample and that of an accused suspect, however, requires reliable estimation of genotype and allele frequencies in the population. Although population-based data on DNA typing at several hypervariable loci are being accumulated at various laboratories, a rigorous treatment of the sample size needed for such purposes has not been made from population genetic considerations. It is shown here that the loci that are potentially most useful for forensic identification of individuals have the intrinsic property that they involve a large number of segregating alleles, and a great majority of these alleles are rare. As a consequence, because of the large number of possible genotypes at the hypervariable loci that offer the maximum potential for individualization, the sample size needed to observe all possible genotypes in a sample is large. In fact, the size is so large that even if such a huge number of individuals could be sampled, it could not be guaranteed that such a sample was drawn from a single homogeneous population. Therefore adequate estimation of genotypic probabilities must be based on allele frequencies, and the sample size needed to represent all possible alleles is far more reasonable. Further economization of sample size is possible if one wants to have representation of only the frequent alleles in the sample, so that the rare allele frequencies can be approximated by an upper bound for forensic applications.     

Some mathematical aspects of the diagnostic process. II: A mathematical model of electrocardiographic diagnosis

In a previous paper (Bartholomay, 1971), a general mathematical model of the medical diagnostic process was described. The present paper amounts to a relization of that process in terms of conventional 12-lead electrocardiographic diagnosis as enunciated by Dr. Harold D. Levine (1966) in the course of a collaborative study by Dr. Levine and the present author at the Peter Bent Brigham Hospital of the Harvard Medical School between 1963 and 1966. The main details of the cognitive component of that model are described in detail here. The model has been programmed onto a computer system consisting of an analog-digital converter and general purpose digital computer and amounts to a simulation of Dr. Levine’s electrocardiographic analysis procedure.     

Genetic Variation and Discriminating Power of Four DNA Microsatellites in the Russian Population

The allele and genotype frequency distributions of four STRs (the LPL, vWA, FES/FPS, and F13B loci) commonly used in forensic medicine were studied with a sample of 200 ethnic Russians from Siberia. Genetic and molecular diversity of the four STRs was characterized in comparison with the American Caucasoid population. The set of the four STRs showed a high power of discrimination (PD = 0.99975). Comparison of the genetic variation at the four loci revealed a considerable difference between the Russian and American Caucasoid populations, precluding the use of data on allele frequencies in American Caucasoids for forensic testing in Russia. The results can be used as a reference in Siberia.     

DXS6804/DXS9896/GATA144D04基因座在中国汉族群体中的遗传多态性及其法医学应用Genetic

为了调查X染色体上DXS6804、DXS9896和 GATA144D04等3个STR基因座在中国汉族群体的遗传多态性及其法医学应用价值,来用PCR和聚丙烯酰胺凝胶电泳对X染色体3个STR基因座进行分型,并检验女性基因型频率分布是否符合Hardy-Weinberg平衡,计算法医学常用各种概率。DXS6804、DXS9896和 GATA144D04的非父排除率分别为0.5990、0.6220、0.4280,表明3个STR基因座在中国汉族群体均具有遗传多态性,χ2检验表明女性的基因型频率分布符合Hardy-Weinberg平衡。X染色体上的基因座DXS6804、DXS9896和 GATA144D04在中国汉族群体中具有较高的遗传多态性,可应用于法医学检验和群体遗传学分析。 Abstract： To investigate the genetic polymorphisms of three short tandem repeats loci of chromosome X in Chinese Han population in Chengdu area and its use in forensic science. Three X-chromosome linked short tandom repeat loci were analyzed by PCR followed by polyacrylamide gel electrophoresis. Hardy-Weinberg equilibrium was tested and forensic interested value was calculated .The power of exlcution of DXS6804、DXS9896和 GATA144D04 is 0.5990、0.6220、0.4280,respectively. The result showed that all the three STR loci were polymorphic among 100 unrelated females and 120 unrelated males from Chinese Han population. χ2 tests demonstrated that genotype frequencies in females did not depart from Hardy-Weinberg equilibrium. Three X-chromosome linked short tandem repeat loci have high polymorphism, they can be applied to forensic medicine and population genetics.     

Genetic variability and discriminating power of four microsatellite loci in Russian population

Allele and genotype frequencies of 4 STR loci (LPL, vWA, FES/FPS H F 13B), used in forensic medicine, were analyzed in Russian Siberian population. Genetic and molecular diversity of these polymorphic systems were characterized in comparison with US Caucasoid population. High discriminating power (PD = 0.99975) of the system of four studied STR loci was shown. Comparative analysis of genetic diversity in Russian population and Caucasoid US population revealed the significant differences between two populations and demonstrated that STR frequency data for US population should not be used for forensic expertise in Russia. The data obtained in the current investigation may be used as reference data for forensic medicine laboratories in Siberia.     

Allele Distribution at the HVR-IgH Hypervariable Locus in Unrelated Individuals Living in the Urals, Siberia, and Northern Kazakhstan

Allelic polymorphism at a hypervariable locus mapped to the 5"-region of the gene cluster encoding J_H segments of human immunoglobulin heavy chain H (IgH-VNTR) was typed in 462 unrelated individuals living in the Urals, Siberia, and Northern Kazakhstan. Molecular characteristics of the three previously unknown IgH-VNTR alleles are presented. The observed genotype frequencies were concordant with those expected under the Hardy–Weinberg distribution. The data obtained can be used in the work of regional forensic laboratories.     

Frequency of HLA-DQA1 alleles in the Japanese population.

One of the HLA class II genes, HLA-DQA1, was typed from 290 unrelated healthy Japanese using the oligonucleotide typing method. The HLA-DQA1 gene was enzymatically amplified and typed by dot-blot hybridizations with 10 sequence-specific oligonucleotide probes labeled nonradioactively. Using this method, the HLA-DQA1 genotype was theoretically classified into 36 genotypes: 8 homozygous and 28 heterozygous ones. Actually, 26 genotypes were observed in the present study, and the gene frequency of each allele was calculated. The observed numbers were in accordance with the numbers expected under the Hardy-Weinberg equilibrium. The HLA-DQA1 genotype was also determined in aged bloodstains. Since the genotype is polymorphic in the Japanese population and a very small amount of blood is required for determination, this typing is particularly useful for forensic analysis.     

The taxonomic rank and place of Colpodellida in the system of the Protista

The analysis of ultrastructure organisation and divergent processes in Colpodellida, Perkinsida, Gregarinea and Coccidea has confirmed the presence of unique basic structures in all of these organisms and the necessity to combine them into the single phylum Sporozoa. A taxonomic rank and place of Colpodellida in the system of living organisms is represented as follows: phylum Sporozoa Leuckart, 1879; em. Krylov, Mylnikov, 1986. (Syn.: Apicomplexa Levine, 1970). Predators or parasites. Common basic structure: pellicular membranes, subpellicular microtubules, micropores, conoid, rhoptries and micronemes, tubular mitochondrial cristae. Class Perkinsea Levine, 1978. Predators or parasites, vegetative stages with two heterodynamic flagella. Subclass 1. Colpodellia nom. nov. (Syn.: Spiromonadia Krylov, Mylnikov, 1986). Predators, two heterodynamic flagella with string-like mastigonemes (if present), division is exclusively within a cyst, with 2-4 daughter cells being produced, extrusomes are trichocyst-like. Subclass 2. Perkinsia Levine, 1978. Parasites, zoospores with two heterodynamic flagella, mastigonemes (if present) bristle-like or string-like.     

Panel of X-linked single-nucleotide polymorphic markers for DNA identification (XSNPid) based on multiplex genotyping by multilocus PCR and MALDI-TOF mass spectrometry

Human genetic markers linked with the X chromosome (X-linked) are used in the field of population and medical genetics, as well as for DNA identification of individuals in forensic science and forensic medicine. We proposed an XSNPid panel that consists of 66 unlinked single nucleotide X chromosome markers and developed a protocol for their multiplex genotyping using multilocus PCR and MALDI-TOF mass spectrometry. The XSNPid panel is genotyped within two multiplexes (36 and 30 markers). The developed protocol provides an efficient genotype reading; the fraction of determined genotypes is 98.29%. The high level of gene diversity (0.461) for the X-linked SNPs included in the panel is characteristic of the Russian population. A total of 63 out of 66 markers that provide a high efficiency of genotyping and independent inheritance are suitable for DNA identification purposes. The XSNPid panel is characterized by a very high discriminating ability when studying the Russian population. The probability of genotype coincidence in two unrelated individuals is 9 × 10^–27 for women and 2 × 10^–18 for men. Also, the XSNPid panel has a greater multiplex capacity in addition to a higher discriminating ability compared to the other closest analogues of the X chromosome SNP sets, which makes it more cost effective and less time consuming. The XSNPid panel is a convenient tool, not only for individual DNA identification, but also for population genetic studies.     

广西环江县毛南族九个短串联重复序列基因座的遗传学分析

为了了解广西环江毛南族人群无关个体的九个短串联重复序列:vWA,D18S51,D5S818,FGA,D8S1179,D21S11,D7S820,D3S1358,D13S317基因座的遗传多态性分布情况;本文用枸橼酸钠抗凝法采集广西环江县毛南族200份无亲缘关系的健康个体的血样,Chelex-100方法提取DNA,应用AmpFlSTRIdentifilerTM荧光标记复合扩增技术对血样DNA的九个STR基因座进行扩增,用ABI 3100型遗传分析仪对扩增产物进行检测。结果显示九个STR位点的基因型分布均符合Hardy-Weinberg平衡定律,累积非父排除率达0.999996,累积个体识别能力达0.99999999996,多态信息总量为0.9999985。结论:广西环江县毛南族人群有自身的STR等位基因分布特征,所获数据可为法医学个体识别、亲子鉴定及群体的遗传学研究提供依据。     

Viols, sperme, spermatozoïdes, identification et paternité médicolégale

The 3 main objectives of DNA analysis in forensic cases are: first, to establish the genetic profile of an evidence sample (the present study deals with semen stains); second, to identify suspects by comparison with the evidence sample genotype; and third, to identify the biological father of a foetus or child by paternity testing. These tests are very strictly controlled in France. Clinicians must be aware of the technical specificities and requirements to avoid interfering with subsequent analysis and/or use of the data in court.     

中国畲族、锡伯族、壮族和藏族Penta E位点的遗传多态性

应用复合PCR扩增技术和荧光毛细管DNA自动电泳分型的方法,使用国产试剂盒,检测Penta E位点在中国畲族、锡伯族、壮族和藏族中的基因频率分布情况。获得了4个民族各约100名无关个体的Penta E位点的等位片段及基因型频率,共发现20个等位片段,其频率分布在0.0048～0.2396之间。各民族的平均杂合度为0.8838,平均个体识别力0.9748,平均非父排除率0.7635,平均多态信息总量0.8950。研究表明Penta E位点属高杂合度、高识别能力的遗传标记,是法庭科学亲子鉴定和个体识别的理想位点。      

湖南土家族群体X染色体10个STR位点的遗传多态性及法医学应用价值评估

对198名湖南土家族健康无关个体抽取静脉血, 提取DNA, 经PCR扩增, 变性聚丙烯酰胺凝胶电泳, 银染进行等位基因分型; 软件SPSS13.0计算各位点基因型频率和等位基因频率, 进行Hardy-Weinberg平衡检验, 并检验基因分布差异有无统计学意义; Fstat软件计算基因多态性及固定指数; Powerstats软件计算各种法医学应用指标。在湖南土家族群体中, 共检出65个等位基因, 频率分布在0.0048～0.6170之间; 10个X-STR位点中DXS6789、DXS6799、HPRTB位点的多态性和分化程度较低; DXS7133、DXS7423位点的法医学应用价值较低; 位点比较中, 湖南土家族群体与德国、意大利群体的差异最明显。DXS6804、DXS7132、DXS7130、DXS8378、DXS6789、DXS6799、DXS7424、HPRTB等8个位点在湖南土家族群体的个体识别和女孩的亲权鉴定中有应用价值, 对疾病相关研究有实际意义; 差异性检验结果揭示高加索人种与蒙古人种间存在着较大的差异性。     

Comparison of VNTR allele frequencies and inclusion probabilities over six populations

There is considerable debate about the methodologies used to estimate VNTR (Variable Number of Tandem Repeats) multi-locus genotype frequencies or odds of inclusion in forensic cases. To compare two of the methods in use, allele frequency distributions among six populations were compared and the effect of population heterogeneity on VNTR multi-locus genotype frequency estimation was examined. Genotype frequencies estimated from single population data were one or two orders of magnitude smaller than those estimated by picking the highest allele frequency in a group of subpopulations to estimate genotype frequencies using a ceiling principle. The average change does not appear to be very sensitive to the set of subpopulations used; four locus frequencies still give inclusion odds of one in a million or less. We think that use of the ceiling principle solves both the statistical problem engendered by subpopulation heterogeneity and the legal problem of assuming that the prepetrator and suspect belong to the same subpopulation. The counterintuitive fact of human genetic polymorphism is that it is easier to identify an individual than it is to identify the subpopulation, ethnic group or race to which that individual belongs.     

用聚合酶链反应和生物素寡核苷酸探针分析HLA-DQα的基因型

 来自不同人的染色体DNA经聚合酶链反应(PCR)将其HLA-DQα基因的多态区242bp人工地扩增30个循环。用1/10扩增产物点在尼龙膜上。将四种不同的等位基因特异的寡核苷酸(ASOs)经Bio-11-duTP进行3'末端标记得生物素探针。以此探针对不同扩增标本做狭缝印迹杂交。结果表明用此种非放射性的方法能探测出人白细胞表面抗原DQα基因的微多态性,从而得到不同个体的基因型。ASO分型是对血清HLA分型的重要补充和发展,它在骨髓或器官移植以及法医的个人识别中有一定实用价值。     

Polymorphic distribution and forensic effectiveness study of eight miniSTR in Chinese Uyghur ethnic group

We obtained the allelic frequencies and forensic efficiency data for eight mini short tandem repeat loci including Penta E, D12S391, D6S1043, D2S1338, D19S433, CSF1PO, Penta D and D19S253 loci from a sample of 128 unrelated Uyghur individuals from China. The amplification products of the eight STR loci are <240 bp in size. A total of 94 alleles were observed and the corresponding allelic frequencies ranged from 0.0039 to 0.3438 in the present study. Observed genotype distributions for each locus do not show deviations from Hardy–Weinberg equilibrium expectations. The combined power of discrimination, combined power of exclusion and combined matching probability of the eight STR loci equaled to 0.999999999963373, 0.9997770 and 3.6627 × 10^?11, respectively. Because of the small fragment length of PCR products and the high degree of polymorphisms, the eight STR loci are highly beneficial for the forensic analysis of degraded DNA samples which are commonly observed in forensic cases. The STR data of the Uyghur group were compared with the previously published population STR data of other groups from different ethnic or areas, and significant differences were observed among these groups at some loci.     

Human Neutral Genetic Variation and Forensic STR Data

The forensic genetics field is generating extensive population data on polymorphism of short tandem repeats (STR) markers in globally distributed samples. In this study we explored and quantified the informative power of these datasets to address issues related to human evolution and diversity, by using two online resources: an allele frequency dataset representing 141 populations summing up to almost 26 thousand individuals; a genotype dataset consisting of 42 populations and more than 11 thousand individuals. We show that the genetic relationships between populations based on forensic STRs are best explained by geography, as observed when analysing other worldwide datasets generated specifically to study human diversity. However, the global level of genetic differentiation between populations (as measured by a fixation index) is about half the value estimated with those other datasets, which contain a much higher number of markers but much less individuals. We suggest that the main factor explaining this difference is an ascertainment bias in forensics data resulting from the choice of markers for individual identification. We show that this choice results in average low variance of heterozygosity across world regions, and hence in low differentiation among populations. Thus, the forensic genetic markers currently produced for the purpose of individual assignment and identification allow the detection of the patterns of neutral genetic structure that characterize the human population but they do underestimate the levels of this genetic structure compared to the datasets of STRs (or other kinds of markers) generated specifically to study the diversity of human populations.     

Detecting sample misidentifications in genetic association studies

Genetic association studies require that the genotype data from a given person can be correctly linked to the phenotype data from the same person. However, sample misidentification errors sometimes happen, whereby the link becomes invalid for some of the subjects in a study. This can have substantial consequences in terms of power to detect truly associated variants. In family-based studies, Mendelian inconsistencies can be used to detect sample misidentification. Genome-wide association studies (GWAS), however, typically use unrelated individuals, making error detection more problematic. Here we present a method for identifying potential sample misidentifications in GWAS and other genetic association studies building on ideas from forensic sciences. A widely used ad-hoc method for error detection is to check if the sex of an individual matches its X-linked genotype. We generalize this idea to less stringent associations between known genotypes and phenotypes, and show that if several known associations are combined, the power to detect misidentifications increases substantially. Individuals with an unlikely set of phenotypes given their genotypes are flagged as potential errors. We provide analytical and simulation results comparing the odds that the genotype and phenotype are both from the same individual for different numbers of available genotype-p henotype associations and for different information content of the associations. Our method has good sensitivity and specificity with as few as ten moderately informative genotype-phenotype associations. We apply the method to GWAS data from the Danish National Birth Cohort.     

Reconstructionist molecular biology

In the editorial inaugurating this journal, Levine (1989) pointed to a new reductionism in biology, which--unlike the old reductionism that led to specialization and isolation of areas concerned with different aspects of a complex biological problem--is providing a renewed sense of unity. This development is the result of widespread use of common experimental methodology and the emergence of signal transmission and differential gene expression as themes that are central to many areas of modern biology. I describe here a set of complementary developments in molecular biology that focus attention on the problems of complexity and organization. Simple examples are given that illustrate the difficulty of relating systemic behavior to the properties of the underlying molecular determinants, and the outlines of a general approach to this problem are presented. These developments, together with those highlighted by Levine, are leading us to a new, more integrative intellectual paradigm whose fruits will be the elucidation of fundamental issues concerning network function, design, and evolution that cannot be addressed by the current paradigm.