动物mtDNA控制区及保守与异质

本文通过文献综述,对动物线粒体DNA控制区进行了阐述.从线粒体控制区（control region）基因组的研究出发,重点介绍了动物线粒体控制区基因组结构特点.主要结论：由于碱基替换、插入和缺失以及重复序列数目的变异致使D-loop成为mtDNA中变异最多的区域,但突变和结构重排并不是发生在整个D-loop区域,而是在高变区;大多研究集中在mtDNA D-loop保守区和异质方面：对D-loop序列分析,能较好地阐明动物的起源,在动物亲缘关系鉴定、系统进化和物种形成方式的研究等领域具有广阔的研究和应用前景.     

动物线粒体DNA重组的研究进展

动物线粒体DNA作为遗传标记广泛用于从种内到高级阶元的许多生物学领域,这些应用是建立在线粒体DNA的严格母系遗传方式和不发生重组的基础上的。近年来的研究提出了一些能够证明动物mtDNA发生重组的直接和间接证据。动物mtDNA重组可能主要通过两条途径发生,一条途径是母系mtDNA与核基因组中mtDNA假基因间发生重组;另一条途径是通过父系渗漏引起的不同单倍型的双亲mtDNA间发生重组。父系渗漏是最可能的途径。如果动物界广泛存在线粒体DNA重组,将会对以mtDNA严格母系遗传为基础的许多应用领域产生重要影响。     

新西兰白兔线粒体基因组全序列的测定与分析

本研究旨在获得新西兰白兔(New Zealand white rabbit)线粒体DNA基因组全序列(mtDNA).根据GenBank已经公布的近缘物种穴兔mtDNA全基因组序列(GenBank登录号:AJ001588.1),设计12对可覆盖新西兰白兔mtDNA全序列的引物,通过PCR扩增、测序、拼接,获得新西兰白兔线粒体全序列,并分析其特点.新西兰白兔线粒体基因组全序列为17 418 bp,A+T含量高,为59.72％,蛋白编码基因数量为13个,rRNA基因数量为2个,tRNA基因数量为22个和1个非编码控制区(D-loop区),与其他兔属动物线粒体全基因组排列顺序一致.分析4种特殊的tRNA二级结构,发现tRNA-Ser(AGY)为二叶草型,缺失DHU臂,其余三种tRNA均为三叶草型.与其他哺乳动物线粒体基因组的D-loop区相比,新西兰白兔与格拉达野兔(Le-pus granatensis)核苷酸组成、编码偏好性和氨基酸组成较为相近.相比穴兔的线粒体基因组,新西兰白兔具有一定的保守性和异质性,该结果为其遗传种质资源保护和利用提供基础资料.     

动物线粒体基因组变异研究进展

动物mtDNA大多是共价闭合的环状双链分子,一般由2个非编码区和37个编码基因组成,不同动物线粒体基因组大小变异明显.孑遗疟虫(Plasmodium reichenowi)的线粒体基因组最小,仅为5966bp;领鞭毛虫(Monosiga brevicollis)的最大,达76568bp.动物线粒体基因组大小变异的原因主要有:控制区串联重复元件的变异;基因重复;基因重叠与基因间隔区大小的差异;基因缺失和增加.     

原生动物线粒体DNA的研究进展

目前已完成了多种原生动物mtDNA全序列的测定,对线粒体基因组有了较全面和深入的认识。本文总结了原生动物线粒体基因组结构、基因组成及基因表达等方面的研究进展,有助于进一步了解原始线粒体基因组的组成及其mtDNA进化,并为细胞的起源和真核生物进化的研究提供有价值的线索。     

基于新一代测序技术的mtDNA突变检测方法学的建立

目的:大量研究证实线粒体DNA(mtDNA)突变与肿瘤发生及进展密切相关,但使用传统测序方法难以高通量、高精确度的检测mtDNA突变,为此本研究建立了基于新一代测序技术的mtDNA突变检测方法.方法:提取肝癌患者癌、癌旁组织以及外周血细胞总DNA,利用PCR技术对线粒体基因组进行富集并对PCR产物进行平末端、粘性末端连接或对PCR引物进行氨基修饰,构建mtDNA测序文库.经Illumina HiSeq 2000平台测序后利用生物信息学方法与人类mtDNA参考序列进行比对,并进行测序数据分析.结果:通过对不同质量基因组DNA进行评估后,发现三对引物法适用于大部分DNA样本的mtDNA富集.进一步我们发现PCR引物的氨基修饰可显著提高测序数据覆盖均一性,降低测序成本.结论:本研究利用新一代测序技术通过对线粒体DNA富集方法以及测序覆盖度均一性进行优化,建立了一套灵敏、特异、高通量的mtDNA突变检测策略,为mtDNA突变与疾病研究提供了新方法.     

蚕类昆虫线粒体DNA研究及其在起源与进化研究中的应用

线粒体DNA(mtDNA)属母系遗传,进化速率较核基因快且基因组结构相对简单,已作为理想的分子标记广泛应用于昆虫群体遗传学及分子系统学等研究。本文对蚕类昆虫线粒体DNA在分子水平上的最新研究进展进行了较详细的阐述,重点介绍了蚕类昆虫线粒体基因组的组成及特征、mtDNA克隆与多态性及在蚕类昆虫分子系统学研究中的应用等。     

鸮形目两种鸟类线粒体基因组全序列测定与比较研究

利用Long-PCR和Primer Walking结合克隆测序法对短耳鸮和长耳鸮线粒体基因组进行了全序列测定. 结果表明: 短耳鸮mtDNA序列全长为18858 bp, 长耳鸮mtDNA全长为18493 bp, 其中短耳鸮mtDNA是目前已知最长的鸟类线粒体基因组. 两种鸮类的基因组结构和基因排列顺序与家鸡相同, 无假控制区, 在ND3基因174位点都存在一个额外插入的胞苷酸(C). 控制区序列异常增大是造成这两种鸟类mtDNA增大的主要原因, 短耳鸮控制区长度为3288 bp, 长耳鸮为2926 bp, 这是目前已知的脊椎动物线粒体基因组中仅次于盲鳗的最大的控制区. 在其控制区3′端存在大量的串联重复序列, 分析发现这两种鸮类的重复序列和Mt5调控元件有较高的序列相似性, 且能形成多重的茎环二级结构, 这表明该重复序列可能具有一定的生理功能, 影响线粒体基因组的复制或转录表达, 从而使相应物种具有更大的选择优势, 以适应环境和生存竞争.     

一种改良的大豆线粒体DNA提取方法

以大豆(Glycine max (L.) Merrill)黄化苗为材料,通过优化提取线粒体DNA(mtDNA)时差速离心过程中的离心力和离心时间,以及纯化过程中设置不同的蔗糖密度梯度和裂解液浓度,结合高盐法去除蛋白质,改良大豆mtDNA的提取方法。结果表明,该方法提取的mtDNA浓度和纯度较高,无叶绿体和核基因组DNA的污染,可用于后续大豆线粒体基因组的相关研究。     

八种植物线粒体基因组结构特征分析与比较

比较来源于GenBank中发表的8种植物(烟草、拟南芥、甜菜、油菜、高粱、水稻、小麦和玉米)线粒体基因组( mtDNA).结果显示,它们共同的特点是编码30 - 40个蛋白,3个核糖体RNA,15 -30个tRNA,G+C含量在40％ -45％之间;各植物线粒体基因组的编码区约占mtDNA的10％ -20％.比较发现,虽然8种作物线粒体基因组大小存在较大差异,基因排列顺序不同,但它们都编码几乎相同的基因产物.     

Thermal habit, metabolic rate and the evolution of mitochondrial DNA

The hallmarks of animal mitochondrial DNA (mtDNA) are a rapid rate of sequence evolution, a small genome carrying the same set of homologous genes, maternal inheritance and lack of recombination. Over the past few years, a variety of different observations has challenged these accepted notions of mitochondrial biology. Notable examples include evidence for variable rates of mtDNA sequence evolution among taxa, evidence for large and variable mitochondrial genome sizes in certain groups, and a growing number of cases in metazoans of 'paternal leakage' in the inheritance of mtDNA. Several recent studies have uncovered different lines of evidence suggesting that an organism's thermal habit, or metabolic rate, can influence the evolution of mtDNA.     

Inheritance of organelle DNA sequences in a citrus-poncirus intergeneric cross

Many land plants deviate from the maternal pattern of organelle inheritance. In this study, heterologous mitochondrial and chloroplast probes were used to investigate the inheritance of organelle genomes in the progeny of an intergeneric cross. The seed parent was LB 1-18 (a hybrid of Citrus reticulata Blanco cv. Clementine x C. paradisi Macf. cv. Duncan) and the pollen parent was the cross-compatible species Poncirus trifoliata (L.) Raf. All 26 progeny examined exhibited maternal inheritance of plastid petA and petD loci. However, 17 of the 26 progeny exhibited an apparent biparental inheritance of mitochondrial atpA, cob, coxII, and coxIII restriction fragment length polymorphisms (RFLPs) and maternal inheritance of mitochondrial rrn26 and coxI RFLPs. The remaining nine progeny inherited only maternal mitochondrial DNA (mtDNA) configurations. Investigations of plant mitochondrial genome inheritance are complicated by the multipartite structure of this genome, nuclear gene control over mitochondrial genome organization, and transfer of mitochondrial sequences to the nucleus. In this study, paternal mtDNA configurations were not detected in purified mtDNA of progeny plants, but were present in progeny DNA preparations enriched for nuclear genome sequences. MtDNA sequences in the nuclear genome therefore produced an inheritance pattern that mimics biparental inheritance of mtDNA.     

Patterns of Mating and Mitochondrial DNA Inheritance in the Agaric Basidiomycete Coprinus Cinereus

Patterns of mating and mitochondrial DNA (mtDNA) inheritance were investigated for the Basidiomycete, Coprinus cinereus in order to better understand the relationship of reproductive biology and mtDNA evolution in fungi. Results showed that the unique mating system of basidiomycetes can lead to the formation of mitochondrial mosaics (i.e., colonies composed of sectors differing in mtDNA). Mitochondria do not migrate along with nuclei during mating. Intracellular mixed or recombinant mtDNA molecules were not observed. Interestingly, it was found that mating asymmetry, caused by nonreciprocal nuclear migration, may be an important part of the reproductive biology of C. cinereus.     

人类线粒体DNA异质性研究进展及其法医学应用

线粒体DNA(mitochondrial DNA mtDNA)的异质性自从被发现以来,一直被遗传学、进化学、发育遗传学以及法医遗传学、分子生物学领域所重视。由于线粒体异质性的存在,使得很多涉及疾病、进化、系统发育线粒体基因组与核基因组的相互作用关系、线粒体DNA复制机制以及法医学运用线粒体DNA进行实际案件评估的问题变得复杂化。此外线粒体DNA异质性的发生原因以及对线粒体异质性的检测方法标准化问题还没有一个统一的答案。针对线粒体DNA异质性带来的种种问题,近年来国内外取得了不少研究进展。     

Cytonuclear coadaptation in Drosophila: disruption of cytochrome c oxidase activity in backcross genotypes

Abstract The cytochrome c oxidase enzyme (COX) is comprised of 10 nuclear-encoded subunits and three mito-chondrial-encoded subunits in close physical association in the inner mitochondrial membrane. COX passes electrons from cytochrome c to molecular oxygen and pumps protons into the inner mitochondrial space for ATP production. Selection on nuclear-mitochondrial interactions within species should lead to coadaptation of the proteins comprising this important enzyme. Under this model, there should be relatively little disruption of COX activity when mitochondrial genomes are crossed among strains within species. A more pronounced disruption of activity is expected when the mitochondrial genome is expressed in the nuclear background of a different species. We test these hypotheses in Drosophila using hybridization and backcrossing among lines of D. simulans and D. mauritiana. Disrupted cytonuclear genotypes were constructed using backcrosses between two lines of D. simulans (siI and si II ) that introduced each divergent mitochondrial DNA (mtDNA) into each nuclear background due to maternal inheritance of mtDNA. Similar crosses were used to introduce eachD. simulans mtDNA into the D. mauritiana maI nuclear background. Reconstituted cytonuclear control genotypes were constructed by backcrossing the initial F1 females to males of the maternal genotype. COX enzyme activities were compared among these disrupted and reconstituted backcross genotypes within and between species. The disruption effect on COX activity was restricted to males of interspecific genotypes. These data support the coadaptation hypothesis and are consistent with predictions that the evolution of modifiers of male mitochondrial dysfunction is hindered by the maternal inheritance of mtDNA. New sequence data for nuclear encoded subunits of COX identified amino acids that may play a role in the disruption effect.     

Human mitochondrial DNA diseases and Drosophila models

Mutations that disrupt the mitochondrial genome cause a number of human diseases whose phenotypic presentation varies widely among tissues and individuals. This variability owes in part to the unconventional genetics of mitochondrial DNA(mtDNA), which includes polyploidy, maternal inheritance and dependence on nuclear-encoded factors. The recent development of genetic tools for manipulating mitochondrial genome in Drosophila melanogaster renders this powerful model organism an attractive alternative to mammalian systems for understanding mtDNA-related diseases. In this review, we summarize mtDNA genetics and human mtDNA-related diseases. We highlight existing Drosophila models of mtDNA mutations and discuss their potential use in advancing our knowledge of mitochondrial biology and in modeling human mitochondrial disorders. We also discuss the potential and present challenges of gene therapy for the future treatment of mtDNA diseases.     

Fate of maternal mtDNA following 60Co inactivation of maternal nuclear DNA in unfertilized salmonid eggs.

The effects of gamma irradiation on nuclear DNA and mitochondrial DNA (mtDNA) were examined by exposing unfertilized salmonid eggs to a 60Co source. Brown trout (Salmo trutta) eggs exposed to 60Co were fertilized with sperm from brook trout (Salvelinus fontinalis), and brook trout eggs exposed to 60Co were fertilized with sperm from splake males (S. namaycush x S. fontinalis). In both types of matings only paternal allozymes were found in embryos, confirming the inactivation of the nuclear genome in the eggs. Analysis of mtDNA in these same embryos showed exclusively maternal mtDNA. The absence of paternal mtDNA among any of the embryos supports the predominance of maternal inheritance of mtDNA in vertebrates and suggests that mtDNAs are more resistant to cobalt inactivation than nuclear DNAs based on structure or numerical superiority to maternal nuclear DNA. Inactivation of maternal nuclear DNA, fertilization, and an induced return to the diploid state provide a means for producing an inbred organism having the nuclear genome of the paternal parent (androgenetic) and the mitochondrial genome of the female.     

Cause or casualty: The role of mitochondrial DNA in aging and age-associated disease

The mitochondrial genome (mtDNA) represents a tiny fraction of the whole genome, comprising just 16.6?kilobases encoding 37 genes involved in oxidative phosphorylation and the mitochondrial translation machinery. Despite its small size, much interest has developed in recent years regarding the role of mtDNA as a determinant of both aging and age-associated diseases. A number of studies have presented compelling evidence for key roles of mtDNA in age-related pathology, although many are correlative rather than demonstrating cause. In this review we will evaluate the evidence supporting and opposing a role for mtDNA in age-associated functional declines and diseases. We provide an overview of mtDNA biology, damage and repair as well as the influence of mitochondrial haplogroups, epigenetics and maternal inheritance in aging and longevity.     

Association between mitochondrial DNA and morphological evolution in Canada geese

Summary Variation within and between eight subspecies of Canada geese was assessed by restriction fragment analysis of mitochondrial DNA (mtDNA), electrophoresis of proteins encoded by nuclear DNA, and the morphometric analysis of skeletons. Estimates of mtDNA sequence divergence between Canada goose subspecies ranged from 0.04 to 2.54%. Pairwise comparisons of the three data matrices revealed that only mtDNA variation and body size are significantly correlated. Subspecies with northern breeding grounds are small-bodied and display small variations of one mtDNA clone, whereas those breeding further south are largebodied and show small differences in another mtDNA clone. Canada geese exhibit strong geographic differentiation with respect to mtDNA sequence, but weak structuring in protein-encoding nuclear DNA. This finding can be explained by a lower level of gene flow for the mitochondrial genome than for the nuclear genome, which in turn emanates from the maternal inheritance of mtDNA and male-biased dispersal in Canada geese. Despite male-mediated flow of nuclear genes, strong morphometric differentiation persists among Canada geese subspecies.     

The incomplete natural history of mitochondria

Mitochondrial DNA (mtDNA) has been used to study molecular ecology and phylogeography for 25 years. Much important information has been gained in this way, but it is time to reflect on the biology of the mitochondrion itself and consider opportunities for evolutionary studies of the organelle itself and its ecology, biochemistry and physiology. This review has four sections. First, we review aspects of the natural history of mitochondria and their DNA to show that it is a unique molecule with specific characteristics that differ from nuclear DNA. We do not attempt to cover the plethora of differences between mitochondrial and nuclear DNA; rather we spotlight differences that can cause significant bias when inferring demographic properties of populations and/or the evolutionary history of species. We focus on recombination, effective population size and mutation rate. Second, we explore some of the difficulties in interpreting phylogeographical data from mtDNA data alone and suggest a broader use of multiple nuclear markers. We argue that mtDNA is not a sufficient marker for phylogeographical studies if the focus of the investigation is the species and not the organelle. We focus on the potential bias caused by introgression. Third, we show that it is not safe to assume a priori that mtDNA evolves as a strictly neutral marker because both direct and indirect selection influence mitochondria. We outline some of the statistical tests of neutrality that can, and should, be applied to mtDNA sequence data prior to making any global statements concerning the history of the organism. We conclude with a critical examination of the neglected biology of mitochondria and point out several surprising gaps in the state of our knowledge about this important organelle. Here we limelight mitochondrial ecology, sexually antagonistic selection, life-history evolution including ageing and disease, and the evolution of mitochondrial inheritance.