ACE基因座外影响循环ACE水平的数量性状基因座

血管紧张素转换酶(ACE)基因16内含子上一段287 bp ALU序列的插入/缺失(I/D)变异与循环ACE水平密切相关.以I/D多态位点为危险标记的病例-对照研究广泛开展,但结果存在差异.ACE基因座外影响循环ACE水平的数量性状基因座(quantitative trait loci,QTL)的发现一定程度上对结果间的差异进行了解释.对决定循环ACE水平QTL的研究,利于对机体循环血压长期调控机制及心脑血管疾病发病机制认识的深入.     

脐血ACE基因多态性与胎膜早破的相关性研究

目的研究脐血血管紧张素转换酶(ACE)基因多态性与胎膜早破的相关性。方法收集2008年4月至2008年11月份在内蒙古妇幼保健院产科分娩的产妇脐带血,设胎膜早破组为实验组,正常足月分娩组为对照组,实验组94例,对照组118例,取脐静脉血3ml,经EDTA抗凝,分别提取基因组DNA,然后用ACE引物进行聚合酶链反应(PCR),对扩增产物进行电泳,测定ACE基因型,分别为DD、ID和II 3种基因型。数据统计分析应用SPSS13.0版统计软件进行统计学分析。结果实验组中ACE基因DD型和D等位基因分布频率明显高于对照组,与对照组比较,P<0.05差异显著。对照组ACE基因型以II型为主,与实验组比较,P<0.05差异显著。ID型在两组间分布频率比较P>0.05,差异无显著性。结论脐血ACE基因多态性与胎膜早破具有密切相关性。     

ACE及其基因多态性与脑血管疾病

ACE基因多态性与ACE血浆浓度有关，且通过不同的遗传机制在心脑血管疾病的发生发展中发挥作用。本文综述了ACE的基本概念及近年对其基因多态性与脑血管疾病相关性研究的进展。     

血管紧张素转换酶（ACE）的遗传多态性：其与血浆ACE水平和…

血管紧张素转换酶（ＡＣＥ）是一种锌金属肽酶（ｚｉｎｃ ｍｃｔａｌｌｏｐｅｔｉｄａｓｅ），在血管生理学中起重要作用，主要涉及肾素－血管紧张素和血管舒缓素－激肽，其底物为血管紧张素Ｉ和缓激肽。     

广东汉族人群血管紧张素转换酶基因（ACE）多态性研究

目的：探讨中国广东汉族群体血管紧张素转换酶基因（ＡＣＥ）第１６内含子中２８７ｂｐ片段的插入／缺失多态性分布。方法：应用ＰＣＲ扩增技术检测２４４名广东籍汉族人ＡＣＥ基因型。结果：广东汉族群体中ＡＣＥ基因插入纯合型Ｉ／Ｉ占４１％;插入和缺失杂合型Ｉ／Ｄ占４０％,缺失纯合型Ｄ／Ｄ占１９％;Ｉ与Ｄ等位基因出现频率分别为０．６２和０．３９。经Ｘ２检验男女之间无显著性差异（Ｐ＞０．０５）。本组资料Ｉ／Ｉ、Ｉ／Ｄ、Ｄ／Ｄ型三种基因频率与中国汉族人群ＡＣＥ基因多态性分布比较均无显著性差异（Ｐ＞０．０５）与日本人群比较发现日本人与广东汉族人Ｉ／Ｉ、Ｉ／Ｄ、Ｄ／Ｄ三种基因分布频率均无显著性差异（Ｐ＞０．０５）。与欧洲英、法、德三国人群比较发现国人的Ｄ／Ｄ发生频率低于上述三国。Ｉ／Ｉ型发生频率则明显高于欧洲三国。结论：本组资料对ＡＣＥ基因Ｉ／Ｄ多态性分析可能有助于从基因水平对防治ＡＣＥ酶相关疾病进行前瞻性研究具有多方面的应用价值。     

新疆吐尔扈特蒙古族人群血管紧张素转换酶（ACE）基因多态性分析

目的: 研究新疆地区吐尔扈特蒙古族人群血管紧张素转换酶(ACE)基因插入/缺失多态性分布情况.方法: 采用聚合酶链反应(PCR)分别检测 82例新疆地区吐尔扈特蒙古族正常人群样本的ACE I/D基因型, 分类计数进行统计学分析.结果: 新疆地区吐尔扈特蒙古族正常人的ACE基因3种基因型频率分别为: DD型 24.39%, ID型 26.83%, Ⅱ型 48.78%.D和I等位基因频率分别为37.80%和62.20%.结论: ACE基因多态性的分布与性别无关, 新疆地区吐尔扈特蒙古族人群ACE基因频率分布与日本人相近, 但DD型及D等位基因频率低于欧美人群.     

非胰岛素依赖型糖尿病患者ACE基因多态性与大、微血管病变关系的研究

目的探讨ACE基因插入／缺失多态性与非胰岛素依赖型糖尿病(non-insulin-dependent diabetes mellitus, NIDDM)患者并发大、微血管病变的关系。方法采用聚合酶链反应技术检测了176例NIDDM患者和50名健康个体ACE基因内含子16插入／缺失多态性。结果对照组与NIDDM组ACE基因型及等位基因频率分布相似(P＞0.05);NIDDM患者DD型亚组冠心病、脑梗塞的频率分别为54%和31%,明显高于II型亚组的22%(P＜0.01)和14%(P＜0.05);NIDDM患者DD型糖尿病肾病的发生率为51%,明显高于II型的31%(P＜0.05)。糖尿病视网膜病变、周围神经病变及任何证据的微血管病变均按II、DI、DD顺序递增(P＞0.05)。结论 ACE基因的D等位基因可增高NIDDM患者并发大、微血管病变的危险性。     

血管紧张素I转换酶基因插入/缺失多态性与人体速度耐力的关联研究

探讨人体血管紧张素I转换酶基因插入/缺失多态性与速度耐力之间的关联性。聚合酶链反应扩增技术检测受试者基因型;测定受试者800 m跑成绩和血乳酸浓度,并对成绩进行逐步聚类分析,将受试者分为高速度耐力组和低速度耐力组。结果发现:高速度耐力组和低速度耐力组组间血管紧张素I转换酶基因型分布及等位基因分布皆无显著性差异(P>0.05);血乳酸浓度无论是安静状态、800 m跑后,还是800 m跑后与安静状态的差值,各基因型组间皆无显著性差异(P>0.05)。人体血管紧张素I转换酶基因插入/缺失多态性与速度耐力无关。     

小儿肾病综合征血管紧张素I转换酶基因多态性研究

目的：探讨ACE基因第16内含子插入／缺失多态性与肾病综合征、血清ACE活性的关系。方法：采用聚合酶链式反应（PCR）检测82例肾病综合征患儿和38例正常儿童ACE基因并同时用酶偶联法测血清ACE活性。结果：①82例肾病综合征患儿中ACE基因Ⅱ型，ID型和DD型频率分别为47．6％（39／82），24．4％（20／82）和28％（23／82）。对照组分别为47．3％（18／38），23．7％（9／38）和29％（11／38），肾病综合征患儿和正常儿童之间ACE基因I／D多态性频率差异无显著性意义（P＞0．05）。②38例正常儿童和82例肾病综合征患儿血清ACE活性比较差异无显著性意义（P＞0．05），ACE各基因型中血清ACE活性差异有显著性意义（P＜0．01），DD型＞ID型＞Ⅱ型。结论：①小儿肾病综合征ACE基因Ⅱ型，ID型和DD型频率分布和正常儿童差异无显著性意义（P＞0．05）。②ACE基因多态性与血清ACE活性密切相关。     

我国人群血管紧张素转换酶基因多态性分布及研究中几个问题

本文介绍了 ACE基因的生物学特性、ACE基因多态性及我国人群 ACE基因分布特点 ,并对 ACE基因与疾病发病机制关系的研究提出了尚需解决的问题。     

Some Properties of a Variance Components Model for Fine-Mapping Quantitative Trait Loci

Identifying etiological variants for multifactorial traits by allelic association holds promise when many markers are available in close proximity. However, evidence for or against association at any particular marker does not provide any direct information about the influence of causal variants or the frequency of the etiologic allele(s). Recently, a variance components model of linkage and association was developed for quantitative traits which is sufficiently flexible to provide some insights into these issues. We show that this combined linkage/association model provides an estimate of the additive genetic variance of a trait that is attributable to disequilibrium between the marker and QTL. We use this estimate to construct approximate boundaries of the minimum level of disequilibrium between an observed marker and unobserved QTL and to delimit the permissible range of allele frequencies at the QTL based on available data at nearby markers. This information may facilitate fine-mapping studies of complex traits that aim to localize QTLs by assessment of association with many markers in a candidate region of interest.     

Identification of Quantitative Trait Loci and Candidate Genes Influencing Ethanol Sensitivity in Honey Bees

Invertebrate models have greatly furthered our understanding of ethanol sensitivity and alcohol addiction. The honey bee (Apis mellifera), a widely used behavioral model, is valuable for comparative studies. A quantitative trait locus (QTL) mapping experiment was designed to identify QTL and genes influencing ethanol vapor sensitivity. A backcross mating between ethanol-sensitive and resistant lines resulted in worker offspring that were tested for sensitivity to the sedative effects of alcohol. A linkage map was constructed with over 500 amplified fragment length polymorphism (AFLP) and sequence-tagged site (STS) markers. Four QTL were identified from three linkage groups with log of odds ratio (LOD) scores of 2.28, 2.26, 2.23, and 2.02. DNA from markers within and near QTL were cloned and sequenced, and this data was utilized to integrate our map with the physical honey bee genome. Many candidate genes were identified that influence synaptic transmission, neuronal growth, and detoxification. Others affect lipid synthesis, apoptosis, alcohol metabolism, cAMP signaling, and electron transport. These results are relevant because they present the first search for QTL that affect resistance to acute ethanol exposure in an invertebrate, could be useful for comparative genomic purposes, and lend credence to the use of honey bees as biomedical models of alcohol metabolism and sensitivity. Edited by Yong-Kyu Kim.     

Mapping Quantitative Trait Loci for Open-Field Behavior in Mice

By performing a whole genome screen in an F₂ intercross of two strains of mice (A/J and C57BL/6J), which differ markedly in their behavioral response to a brightly lit open field (O-F), we have mapped several quantitative trait loci (QTL) for this complex behavioral phenotype. QTL on chromosomes 1 and 10 were identified that affect both initial ambulation in the O-F (initial response to novelty ambulation) (lod of 7.1 and 8.8, respectively) and vertical rearings (lod of 4.5 and 8.5, respectively). For habituated O-F behavior, QTL were identified on chromosomes 3 and 10 for ambulation (lod of 4.1 and 14.7, respectively) and on chromosomes 1, 10, and 19 for vertical rearings (lod of 5.8, 6.0, and 4.7, respectively). The QTL on chromosome 1 (near D1Mit1 16; 101 cM) was specific for initial O-F ambulation behavior, whereas the QTL on chromosome 10 (near D10Mit237; 74 cM) affected both initial and habituated rearing behavior. Additional suggestive QTL (lod, >2.8) were mapped to chromosomes 1, 8, 11, 15, and 19. The QTL on chromosomes 1, 10, and 19 individually explain from 3.2 to 12.7%. Collectively, the multiple independent QTL explain from 16.3 to 24.1% of the F₂ population's phe-notypic variance, depending on the trait. These identified QTL should prove useful for dissecting the genetic and behavioral dimensions of O-F behavior, fostering an understanding of individual differences.     

Mapping Multiple Quantitative Trait Loci for Ordinal Traits

Many complex traits in humans and other organisms show ordinal phenotypic variation but do not follow a simple Mendelian pattern of inheritance. These ordinal traits are presumably determined by many factors, including genetic and environmental components. Several statistical approaches to mapping quantitative trait loci (QTL) for such traits have been developed based on a single-QTL model. However, statistical methods for mapping multiple QTL are not well studied as continuous traits. In this paper, we propose a Bayesian method implemented via the Markov chain Monte Carlo (MCMC) algorithm to map multiple QTL for ordinal traits in experimental crosses. We model the ordinal traits under the multiple threshold model, which assumes a latent continuous variable underlying the ordinal phenotypes. The ordinal phenotype and the latent continuous variable are linked through some fixed but unknown thresholds. We adopt a standardized threshold model, which has several attractive features. An efficient sampling scheme is developed to jointly generate the threshold values and the values of latent variable. With the simulated latent variable, the posterior distributions of other unknowns, for example, the number, locations, genetic effects, and genotypes of QTL, can be computed using existing algorithms for normally distributed traits. To this end, we provide a unified approach to mapping multiple QTL for continuous, binary, and ordinal traits. Utility and flexibility of the method are demonstrated using simulated data.     

Interaction Between Two Quantitative Trait Loci Affects Fetal Haemoglobin Expression

The biological mechanisms controlling complex quantitative traits are likely to be affected by interactions between genetic factors, sometimes referred to as epistasis. The identification of interacting loci through genetic analyse faces many challenges, and few examples of replicated findings of interaction exist for humans and model system organisms. The replication of an interaction, or the non‐independence, of two quantitative trait loci (QTL) affecting the developmental switch from the expression of fetal to adult haemoglobin is reported here. Fetal haemoglobin expression in adults is a highly heritable, yet complex, phenotype. Using a sample of 874 dizygotic twin pairs of European descent, we found linkage to a QTL on chromosome 8 to be conditional on the twin pairs' genotypes at a polymorphism in the β‐globin complex; an interaction originally identified in a large Asian Indian kindred. The β‐globin polymorphism has been previously shown to be associated with fetal haemoglobin levels in adults. This study reports the first known replication of a genetic interaction between QTLs influencing a complex human trait.     

ACE基因I/D多态性在心血管疾病中的研究进展

血管紧张素转化酶（ACE）是肾素-血管紧张素-醛固酮系统（RAAS）的关键酶，在心血管疾病发生发展中起重要作用。近年来有多个研究探讨ACE基因插入/缺失（insertion/ deletion,I/D）多态性与心血管疾病之间的关系，然研究结果尚存争议。本文主要就ACE基因I/D的多态性及其与心血管疾病关系的研究进展做一综述。     

Quantitative Trait Loci Associated with Reversal Learning and Latent Inhibition in Honeybees (Apis mellifera)

A study was conducted to identify quantitative trait loci (QTLs) that affect learning in honeybees. Two F₁ supersister queens were produced from a cross between two established lines that had been selected for differences in the speed at which they reverse a learned discrimination between odors. Different families of haploid drones from two of these F₁ queens were evaluated for two kinds of learning performance—reversal learning and latent inhibition—which previously showed correlated selection responses. Random amplified polymorphic DNA markers were scored from recombinant, haploid drone progeny that showed extreme manifestations of learning performance. Composite interval mapping procedures identified two QTLs for reversal learning (lrn2 and lrn3: LOD, 2.45 and 2.75, respectively) and one major QTL for latent inhibition (lrn1: LOD, 6.15). The QTL for latent inhibition did not map to either of the linkage groups that were associated with reversal learning. Identification of specific genes responsible for these kinds of QTL associations will open up new windows for better understanding of genes involved in learning and memory.     

Cardiac and renal distribution of ACE and ACE-2 in rats with heart failure

Congestive heart failure is often associated with impaired kidney function. Over-activation of the renin–angiotensin–aldosterone system (RAAS) contributes to avid salt and water retention in heart failure. While the expression of angiotensin converting enzyme (ACE), a key enzyme in the synthesis of angiotensin II (Ang II), is well established, the expression of angiotensin converting enzyme-2 (ACE-2), an enzyme responsible for angiotensin 1–7 generation, is largely unknown. This issue is of a special interest since angiotensin 1–7 counteracts many of the proliferative and hypertensive effects of angiotensin II. Therefore, the present study was designed to investigate the expression of both enzymes in the kidney and heart of rats with heart failure. Heart failure (CHF) was induced in male Sprague Dawley rats (n = 9) by the creation of a surgical aorto-caval fistula. Sham-operated rats served as controls (n = 8). Two weeks after surgery, the animals were sacrificed and their hearts and kidneys were harvested for assessment of cardiac remodeling and ACE and ACE-2 immunoreactivity by immunohistochemical staining. ACE immunostaining was significantly increased in the kidneys (4.34 ± 0.39% vs. 2.96 ± 0.40%, P < 0.05) and hearts (4.57 ± 0.54% vs. 2.19 ± 0.37%, P < 0.01) of CHF rats as compared with their sham controls. In a similar manner, ACE-2 immunoreactivity was also elevated in the kidneys (4.65 ± 1.17% vs. 1.75 ± 0.29%, P < 0.05) and hearts (5.48 ± 1.11% vs. 1.13 ± 0.26%, P < 0.01) of CHF rats as compared with their healthy controls. This study showed that both ACE and ACE-2 are overexpressed in the cardiac and renal tissues of animals with heart failure as compared with their sham controls. The increased expression of the beneficial ACE-2 in heart failure may serve as a compensatory response to the over-activity of the deleterious isoform, namely, angiotensin converting enzyme 1(ACE-1).     

Identification of Quantitative Trait Loci Influencing Alcohol Consumption in the High Alcohol Drinking and Low Alcohol Drinking Rat Lines

Selective breeding has been employed to develop high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rat lines from the heterogeneous N/Nih rat. Within-family selection and a rotational breeding design were used to discourage inbreeding (Li et al, 1993). To identify quantitative trait loci (QTLs) contributing to alcohol consumption, reciprocal HAD and LAD matings in conjunction with F1 intercrosses were used to create 459 F2 progeny. Using selective genotyping of 151 F2 progeny with extreme alcohol consumption scores and a novel least squares method developed by Haley et al (1994), five chromosomal regions (1,5,10,12, and 16) were identified with lod scores greater than 2.0. Genotyping of the entire sample of 459 F2 progeny produced maximum lod scores of 3.5 on chromosome 5, 2.4 on chromosome 10, 4.7 on chromosome 12 and 2.9 on chromosome 16. The evidence of linkage to chromosome 1 diminished substantially to a maximum lod score of 0.5 when all F2 progeny were genotyped. This study is the first genome-wide study for QTLs underlying alcohol consumption that has employed noninbred lines. Further localization of these QTLs will likely provide insight and candidate genes for the study of human alcoholism.