4种昆虫基因组中的线粒体假基因

为了进一步了解昆虫核基因组中线粒体假基因(Numts)序列分布情况,避免Numts序列对基于线粒体DNA(mtDNA)进行系统发育关系研究结果的误导,利用Blast N对GenBank中已完成核基因组和mtDNA测序的4种昆虫核基因组中的Numts序列进行检索,结果表明:冈比亚按蚊Anopheles gambiae中没有Numts序列;黑腹果蝇Drosophila melanogaster中仅有少量Numts序列;赤拟谷盗Tribolium castaneum和意大利蜜蜂Apis melliera基因组中Numts序列超过100条,尤其是意大利蜜蜂中的Numts序列涵盖全部mtDNA.ND2,ND4,ND5,COⅠ与lrRNA向核内转移频率高于其他mtDNA基因片段,因此,在使用其进行系统发育关系研究时需加倍谨慎.     

DNA序列在植物系统进化研究中的应用

DNA序列分析已广泛应用于植物系统与进化学研究，根据不同的研究对象和问题选择相对应的DNA序列来进行研究显得十分重要。目前在植物系统与进化学中主要一些DNA的应用，主要是讨论叶绿体基因组（rbcL等）和核基因组（18S，ITS）中的特定DNA序列区段。研究表明，18S,rbcL等编码基因一般适用于较高分类阶元甚至整个种子植物谱系间的系统发育的探讨，而ITS极cpDNA的非编码区序列等因其较快的进化速率多用于较低分类阶元的系统关系研究。     

鱼类线粒体基因组研究进展

线粒体基因组(mitochondrial genome DNA,mtDNA)具有严格的母系遗传且能进行自我复制,并且在世代传递过程中不易发生重组、进化速率较快等优点.因此mtDNA广泛应用于系统进化、种群遗传、适应性进化等领域中.本文对鱼类mtDNA研究做了详细阐述,系统总结了近年来鱼类mtDNA结构与特征、线粒体的起源与演化、种群遗传、适应性进化、鱼类条形码物种识别等研究进展,以期对相关研究有一定参考价值.     

动物mtDNA的研究及在鱼类生态学中的应用

概述了动物线粒体的主要特征、动物线粒体DNA(mtDNA)的结构特点、多态和进化；以及线粒体DNA多态研究方法，最后介绍了动物mtDNA的多态性在研究鱼类群体遗传结构上的应用。     

基于相对熵原理构建生物进化系统树

根据相对熵原理定义了物种进化距离,把它应用到基于DNA序列分析的生物进化系统树构建的研究中.首先选用64种脊椎动物的线粒体DNA序列为材料,得到与传统的根据物种形态构建的系统树基本一致的树形;进而进行全基因组序列层次的物种进化的研究,选取长度约为线粒体DNA序列102倍的12种古生菌、真细菌全序列,最终也得到了合理的系统树.     

鸟类线粒体基因组及系统发育的研究进展

相对于核基因组而言,线粒体基因组具有结构简单、分子量小、基因排列紧密、严格母系遗传、进化速率较快和无组织特异性等特点。近年来,线粒体DNA已被作为重要的分子标记,应用于推断很多分类等级的系统发育关系。本文综述了脊椎动物线粒体基因组、鸟类线粒体基因组以及Mt DNA在鸟类系统发育研究中的应用等方面的研究现状,并对今后研究前景进行了展望。     

从微量血中快速制备线粒体DNA片段

目的　建立并鉴定用于从微量血中快速制备线粒体DNA片段的技术 .方法　采用微量血样品 ,改进提取线粒体DNA的方法 ;以不同的方法提取的血DNA为模板 ,同时扩增nDNA上的基因片段和mtDNA上的基因片段 ,PCR相对定量分析比较各种方法提取的mtDNA片段的纯度 ;结果　用华美公司生产的ReadyPCR(tm)微量全血DNA纯化系统和作者的方法都得到了mtDNA ,而用作者的方法获得的mtDNA的纯度较高 ;结论　由于线粒体DNA与核DNA存在有同源片段 ,ReadyPCR(tm)微量全血DNA纯化系统和常规酶解法提取DNA不适合用于对mtDNA的鉴定 ,作者的方法简便快捷地排除了核DNA的污染 ,非常适合于对mtDNA进行PCR分析 .     

论生物基因组的起源和进化

通过分析核基因组、线粒体基因组和叶体基因组的大小与结构，发现这三种基因组教师阴“小基因组”和“大基因组”的形式及与之对应的结构特点，认为它们各自的祖先都是通过分别与“小基因组”和“大基因组”相应的两种途径进化成成为现象核（类核）基因组、线粒体基因组和叶绿体基因组，发展了生物基因组起源和进化的统一模式。     

茄子雄性不育株和可育株的胞质DNA和核DNA差异分析

以茄子(Solanum melongenaL)雄性不育株“正兴1号”(S)和可育株(F)的总DNA为模板,对60个随机引物进行了筛选,找到5个其RAPD(Random amplified polymorphic DNA,RAPD)扩增产物在茄子雄性不育系和对照材料间存在稳定差异的引物．将该5个引物同时扩增总DNA、核DNA和线粒体DNA(mitochondrial DNA,mtDNA)．以总DNA为模板时得到多态性片段9个,以核DNA为模板时得到5个,以mtDNA为模板时得到9个．以总DNA为模板时得到的9个扩增片段中,有5个在总DNA和mtDNA中同时出现,而在核中没有出现,即认为来自mtDNA,这5个片段中,有4个来自可育株,1个来自不育株,说明不育株和可育株在mtDNA上存在差异;有4个片段同时出现在以总DNA和核DNA为模板的扩增中,但在以mtDNA为模板的扩增中却没有出现,认为是来自核DNA,这4个片段中,有3个来自不育株,一个来自可育株,说明可育株和不育株在核DNA上也存在差异．结果初步表明：新发现的茄子雄性不育可能是核质相互作用所引起．     

蝗虫cyt b基因部分序列的多样性和分子系统学研究

利用蝗虫线粒体DNA(mtDNA)基因组中细胞色素b(cyt b)基因部分序列,研究其系统进化关系,所测序列与黑尾果蝇的同源序列一起经Clustal X1．8软件比对,选定46条片段均为432 位点的cyt b基因序列,其中变异位点共有137个;选定13条片段均为258个位点的cyt b基因序列,其中变异位点共有72个;选定27条片段均为640位点的cyt b基因序列,其中变异位点有235 个．利用MEGA 2．1软件,以黑尾果蝇为外群,用p-distance及k-2参数模型、N-J法和ME法构建系统进化树．对蝗虫的系统进化关系进行了研究,确定其分类地位,并对蝗虫进化关系进行初步探讨．     

Evolutionary genetics. Clonal inheritance of avian mitochondrial DNA.

We have taken a new approach to test the commonly accepted, but recently questioned, principle of clonal inheritance of vertebrate mitochondrial DNA (mtDNA) by relating its inheritance to a female-specific marker of nuclear DNA. Whereas this is impossible in organisms with male heterogamy (such as mammals), we show here that genealogies of mtDNA and the female-specific W chromosome of a bird species are completely concordant. Our results indicate that inheritance of mtDNA is free of detectable recombination effects over an evolutionary timescale.     

DNA ligase III is critical for mtDNA integrity but not Xrcc1-mediated nuclear DNA repair

DNA replication and repair in mammalian cells involves three distinct DNA ligases: ligase I (Lig1), ligase III (Lig3) and ligase IV (Lig4). Lig3 is considered a key ligase during base excision repair because its stability depends upon its nuclear binding partner Xrcc1, a critical factor for this DNA repair pathway. Lig3 is also present in the mitochondria, where its role in mitochondrial DNA (mtDNA) maintenance is independent of Xrcc1 (ref. 4). However, the biological role of Lig3 is unclear as inactivation of murine Lig3 results in early embryonic lethality. Here we report that Lig3 is essential for mtDNA integrity but dispensable for nuclear DNA repair. Inactivation of Lig3 in the mouse nervous system resulted in mtDNA loss leading to profound mitochondrial dysfunction, disruption of cellular homeostasis and incapacitating ataxia. Similarly, inactivation of Lig3 in cardiac muscle resulted in mitochondrial dysfunction and defective heart-pump function leading to heart failure. However, Lig3 inactivation did not result in nuclear DNA repair deficiency, indicating essential DNA repair functions of Xrcc1 can occur in the absence of Lig3. Instead, we found that Lig1 was critical for DNA repair, but acted in a cooperative manner with Lig3. Additionally, Lig3 deficiency did not recapitulate the hallmark features of neural Xrcc1 inactivation such as DNA damage-induced cerebellar interneuron loss, further underscoring functional separation of these DNA repair factors. Therefore, our data reveal that the critical biological role of Lig3 is to maintain mtDNA integrity and not Xrcc1-dependent DNA repair.     

系统地理学的研究及其在鱼类上的应用

介绍了系统地理学的研究内容、理论、方法,重点介绍了AVISE的5种物种分布模式、中性溯祖理论、mtDNA多态性分析的优越性以及TEMPLETON的巢式支系法。还从地理隔离、种群扩散、基因交流、区系划分、分子钟估算等方面阐述了系统地理学在鱼类的应用研究现况和应用前景。最后提出了系统地理学在鱼类应用时要注意的事项:1)要选择合适的基因DNA片段进行分析;2)mtDNA标记最好要与核DNA标记及形态学、细胞学、生化学标记结合使用;3)要提高分子钟估算的精确度。     

线粒体病的分子生物学机制

线粒体病是一种少见的能量代谢病,病情复杂多样,从单一组织损伤或无明显临床症状到多系统发病乃致患者早期死亡,在临床上容易误诊或漏诊,甚至延误治疗.由于线粒体的结构与功能受核基闪组(nDNA)与线粒体基冈组(mtDNA)双重调控,其中大多数线粒体酶、结构蛋白和各种蛋白因子由nDNA编码,因而多数原发性线粒体病是nDNA突变...     

Evidence from mitochondrial DNA that African honey bees spread as continuous maternal lineages

African honey bees have populated much of South and Central America and will soon enter the United States. The mechanism by which they have spread is controversial. Africanization may be largely the result of paternal gene flow into extant European populations or, alternatively, of maternal migration of feral swarms that have maintained an African genetic integrity. We have been using both mitochondrial and nuclear DNA restriction fragment length polymorphisms to follow the population dynamics between European and African bees. In earlier reports, we suggested that if African honey bees had distinctive mitochondrial (mt) DNA, then it could potentially distinguish the relative contributions of swarming and mating to the Africanization process. Because mtDNA is maternally inherited, it would not be transmitted by mating drones and only transported by queens accompanying swarms. Furthermore, the presence of African mtDNA would reflect unbroken maternal lineages from the original bees introduced from Africa. The value of mtDNA for population studies in general has been reviewed recently. Here we report that 19 feral swarms, randomly caught in Mexico, all carried African mtDNA. Thus, the migrating force of the African honey bee in the American tropics consists of continuous African maternal lineages spreading as swarms. The mating of African drones to European queens seems to contribute little to African bee migration.     

中国猛禽类线粒体DNA遗传多态性研究进展

鸟类线粒体ＤＮＡ的研究在种群生物学和进化生物学研究方面越来越显示出重要的作用,特别是在遗传多态性和基因流研究方面更具特殊意义。简要回顾了鸟类线粒体ＤＮＡ的研究历史,并分析了中国猛离线粒体ＤＮＡ遗传多态性的研究现状及进展,要点：１．猛禽类线粒体基因组大小存在遗传多态性,２：猛禽类线粒体ＤＮＡ的进化速率与哺乳类相同,３;种间或种内存在丰富的遗传变异;４．不同地理种群存在ｍｔＤＮＡ克隆群的连续性。     

Deletions of muscle mitochondrial DNA in patients with mitochondrial myopathies

In vitro studies of muscle mitochondrial metabolism in patients with mitochondrial myopathy have identified a variety of functional defects of the mitochondrial respiratory chain, predominantly affecting complex I (NADH-CoQ reductase) or complex III (ubiquinol-cytochrome c reductase) in adult cases. These two enzymes consist of approximately 36 subunits, eight of which are encoded by mitochondrial DNA (mtDNA). The increased incidence of maternal, as opposed to paternal, transmission in familial mitochondrial myopathy suggests that these disorders may be caused by mutations of mtDNA. Multiple restriction endonuclease analysis of leukocyte mtDNA from patients with the disease, and their relatives, showed no differences in cleavage patterns between affected and unaffected individuals in any single maternal line. When muscle mtDNA was studied, nine of 25 patients were found to have two populations of muscle mtDNA, one of which had deletions of up to 7 kilobases in length. These observations demonstrate that mtDNA heteroplasmy can occur in man and that human disease may be associated with defects of the mitochondrial genome.