线粒体DNA和人类进化

通过对线粒体DNA(mtDNA)全序列的限制性酶切和D-环高变区序列数据的分析,mtDNA较好地阐明了人类学中诸如现代人类起源、人群过去动态的估计以及单个人群的区域性微分化和人口历史学等问题。综述了近年来世界各人群mtDNA的研究进展、研究方法的改进、mtDNA与核基因标记结果的异同、mtDNA与语言的协同进化关系、古老DNA研究以及当前关于这种遗传标记本身遗传特性的争论。

云南保种山羊线粒体DNA限制性酶切研究

　采用碱变性法,提取来自云南省不同地区4个保种山羊的13个个体的线粒体DNA(mtDNA),并用ApaⅠ,AvaⅠ,BamHⅠ,BclⅠ,BcIⅠ，BglⅡ,ClaⅠ,DraⅠ, EcoRⅠ,EcoRⅤ,HaeⅠ,HindⅢ,KpnⅠ,PstⅠ,PvuⅡ,SacⅠ,SalⅠ,SmaⅠ,StuⅠ和XhoⅠ等20种限制性内切酶进行酶切分析。结果发现它们的线粒体DNA的分子量大 小约为15.8Kb；不同限制性内切酶的酶切位点分别为：DraⅠ有7个酶切位点，AvaⅢ有6个酶切位点，EcoRⅤ和StuⅠ共有5个酶切位点，HindⅡ和HaeⅡ有4个酶 切位点，BamHⅠ,BglⅡ,PstⅠ和PvuⅡ有3个酶切位点，ApaⅠ，ClaⅠ有两个酶切位点，其余有1个酶切位点。各保种山羊间未发现变异，说明云南的4个保种山 羊极可能来自于共同的母性祖先。

真核生物DNA甲基化作用与基因突变(英文)

迄今为止, 不少人认为5-甲基胞嘧啶的存在可能是基因突变的“热点”. 然而, 事实上5-甲基胞嘧啶作为一种稀有碱基, 本来就是许多真核生物 DNA 的正常组分. 它的存在也是真核生物DNA的特征之一. 作者几年来所作的理论研究表明, 5-甲基胞嘧啶不可能是基因突变的“热点”. 由胞嘧啶甲基化成为5-甲基胞嘧啶, 再经水解脱氨成为胸腺嘧啶的反应(C→m~(5)C→T)在正常生理条件下是不太可能发生的. 在真核生物DNA中, G—C碱基对转变为A—T碱基对的反应可能是由互变异构碱基配对或其它因素引起的。

云南龙陵黄山羊线粒体DNA限制性酶切分析

采用碱性变性法提取来自于龙陵县不同地区的18只黄山羊个体的线粒体DNA(mtDNA),并用Apa I、Ava I、BamH I、Bcl I、Bgl I、Bgl II、Cla I、Dra I、EcoR I、EcoR V、Hae I、Hind III、Kpn I、Pst I、Pvu II、Sac I、Sal I、Sma I、Stu I和Xba I等20种限制性内切酶进行酶切分析。 结果发现龙陵黄山羊线粒体DNA的分子量大小约为15.8Kb;不同酶的酶切位点分别为:Dra I有7个酶切位点,Ava II有6个酶切位点,EcoR V和Stu I共有5个酶切位点,Hind III和Hea II有4个酶切位点,BamH I、Bgl II、Pst I和Pvu II有3个酶切位点,Apa I、Cla I有2个酶切位点,其余有1个酶切位点。

Rapid and parallel chromosomal number reductions in muntjac deer inferred from mitochondrial DNA phylogeny

Muntjac deer (Muntiacinae, Cervidae) are of great interest in evolutionary studies because of their dramatic chromosome variations and recent discoveries of several new species. In this paper, we analyze the evolution of karyotypes of muntjac deer in the context of a phylogeny which is based on 1,844-bp mitochondrial DNA sequences of seven generally recognized species in the muntjac subfamily. The phylogenetic results support the hypothesis that karyotypic evolution in muntjac deer has proceeded via reduction in diploid number. However, the reduction in number is not always linear, i.e., not strictly following the order: 46-->14/13-->8/9-->6/7. For example, Muntiacus muntjak (2n = 6/7) shares a common ancestor with Muntiacus feae (2n = 13/14), which indicates that its karyotype was derived in parallel with M. feae's from an ancestral karyotype of 2n greater than or equal to 13/14. The newly discovered giant muntjac (Muntiacus vuquangensis) may represent another pa;allel reduction lineage from the ancestral 2n = 46 karyotype. Our phylogenetic results indicate that the giant muntjac is relatively closer to Muntiacus reevesi than to other muntjacs and may be placed in the genus Muntiacus. Analyses of sequence divergence reveal that the rate of change in chromosome number in muntjac deer is one of the fastest in vertebrates. Within the muntjac subfamily, the fastest evolutionary rate is found in the Fea's lineage, in which two species with different karyotypes diverged in around 0.5 Myr.

鱇(鱼良)白鱼线粒体DNA控制区结构和种群遗传多样性分析

用特异性引物对鱇(鱼良)白鱼(Anabarilius grahami)DNA进行PCR扩增,获得了鱇(鱼良)白鱼线粒体DNA控制区基冈全序列(930bp).控制区T、C、A和G碱基组成为29.8%、22.5%、33.0和14.7%.对照其他已报道的鱼类控制区结构,对鱇(鱼良)白鱼控制区结构进行了分析,识别了其终止序列区、中央保守区和保守序列区,找到了终止相关的序列TAS以及保守序列(CSB-F、CSB-D、CSB-1、CSB-2、CSB-3).同时运用DNA分析软件对鱇(鱼良)白鱼一个驯养种群(中国科学院昆明动物研究所珍稀鱼类繁育中心)及两个自然地理种群(江川县明星鱼洞、江川县牛摩村)进行了遗传多样性分析.结果显示:两个自然种群存在较强基因交流,未出现遗传分化;人工驯养种群遗传多样性最高,种群复壮程度较好.

滇池铜绿微囊藻(M．aeruginosa zosa Kutz)的分离培养与总DNA提取的改进

利用稀释法结台平板分离培养法将采自滇池水华中的铜绿微囊藻进行了成功的 分离纯化对比纯化培养前后，发现纯化后该藻的生长速度明显加快，密度大为提高，约为纯化前 的5倍用乙醇乙醚混合液剐该藻作预处理后，破坏了其胶质被．再经常规方法提取总DNA，其得 率提高3 4倍

DNA 拓扑异构酶Ⅱ的结构和作用原理

1976年美国国立卫生研究所的 Gellert 等从大肠杆菌中提取到解旋酶 (gyrase, 也叫细菌DNA 拓扑异构酶Ⅱ ,以下简称 TopoⅡ )以来, 对 TopoⅡ的作用机制一直存在争议. Tse (1980)报道, Topo Ⅱ能同时打断 DNA 的两条链,TopoⅡ的两个亚基键分别与断开的 DNA 的两个5'末端连接, 并互相错开4个碱基对，以便让另一股 DNA 双链通过。

基于部分线粒体细胞色素氧化酶亚基Ⅰ(mtCOI)DNA 序列的6种蝙蝠(翼手目:蝙蝠科)的分子系统进化关系

对贵州5种蝙蝠科蝙蝠的部分线粒体细胞色素氧化酶亚基Ⅰ DNA序列进行了测定,并结合从Genbank获得的爪哇伏翼的相应序列,以Pteropus dasymallus,P.scapulatus,Rousettus aegyptiacus为外群,运用贝叶斯法(Bayesian),最大似然法(Maximum Likelihood,ML)分析了这6种蝙蝠科蝙蝠的分子系统进化关系.结果表明:在贝叶斯,ML树中,这6种蝙蝠科的蝙蝠可分为3个分支:亚洲长翼蝠是第1个独立出来的分支;白腹管鼻蝠是继亚洲长翼蝠之后第2个分离出来的分支;第3个分支又分为两支,一支由大鼠耳蝠和小鼠耳蝠组成,另一支由南蝠和爪哇伏翼组成,支持将这4种蝙蝠同归于蝙蝠亚科的结论,从一定程度上否定了鼠耳蝠属和管鼻蝠亚科之间的姐妹类群关系,也不支持将鼠耳属提升为亚科.

胞嘧啶甲基化对DNA精细结构的影响

DNA 中胞嘧啶甲基化及其在基因调控中的作用, 是一个很有兴趣的生物学问题. 该文以d(CGCGAATTCGCG)为对象用分子模建、能量优化、均方根偏离分析等方法, 从理论上探讨了胞嘧啶甲基化对 DNA 精细结构起伏的影响, 证实了甲基化作用主要引起5-甲基胞嘧啶所在局部位置的DNA精细结构发生变化, 而糖链部分发生的变化远大于碱基部分发生的变化。

两个家系猪的DNA指纹图谱遗传分析

用人源小卫星探针33.6和33.15获得了两个家系猪的DNA指纹图谱。通过对F1和F2代家系分析,证实DNA指纹图带以孟德尔方式遗传。在家系2(探针33.6)的1个后代中发现了一条新突变带。文中还对这两个探针检测到的位点数进行了估测。

Variation in mitochondrial DNA and phylogeny of six species of pikas (Ochotona)

Phylogenetic relationships of six species of Ochotona were investigated using mitochondrial DNA (mtDNA) restriction-site analysis. The phylogenetic tree constructed using PAUP was based on 62 phylogenetically informative sites with O. erythrotis designated as an outgroup. Two clades were evident. One contained O. curzoniae, O. huangensis, and O. thibetana. in the second, O. daurica was a sister taxon of O. cansus. The five species appear to come from different maternal lineages. The branching structure of the tree and sequence divergence confirm that huangensis and cansus are distinct species, and that mol-osa is a synonym of O. cansus rather than O. thibetana. Divergence time, estimated from genetic distances, indicates that the ancestors of the two maternal lineages diverged ca. 6.5 x 10(6) years ago. O. curzoniae diverged from O. huangensis, and O. daurica diverged from O. cansus, at about the same time (ca. 3.4 x 10(6) years ago). These data suggest a period of rapid radiation of the genus Ochotona in China, perhaps during the late Pliocene. These calculations correspond roughly to tectonic events and environmental changes in China throughout this period, and appear to be substantiated by the fossil record.

Comparative studies on parallel and antiparallel duplex and triplex DNA

Parallel strand models for base sequences d(A)(10). d(T)(10), d(AT)(5) . d(TA)(5), d(G(5)C(5)). d(C(5)G(5)), d(GC)(5) . d(CG)(5) and d(CTATAGGGAT). d(GATATCCCTA), where reverse Watson-Crick A-T pairing with two H-bonds and reverse Watson-Crick G-C pairing with one H-bond or with two H-bonds were adopted, and three models of d(T)(14). d(A)(14). d(T)(14) triple helix with different strand orientations were built up by molecular architecture and energy minimization. Comparisons of parallel duplex models with their corresponding B-DNA models and comparisons among the three triple helices showed: (i) conformational energies of parallel AT duplex models were a little lower, while for GC duplex models they were about 8% higher than that of their corresponding B-DNA models; (ii) the energy differences between parallel and B-type duplex models and among the three triple helices arose mainly from base stacking energies, especially for GC base pairing; (iii) the parallel duplexes with one H-bond G-C pairs were less stable than those with two H-bonds G-C pairs. The present paper includes a brief discussion about the effect of base stacking and base sequences on DNA conformations. (C) 1997 Academic Press Limited.

牛山湖浮游生物群落DNA指纹结构与物种组成的关系

利用RAPD及DGGE指纹技术揭示牛山湖5个采样点浮游生物群落的DNA多态性,并定性地探讨其与物种组成的关系。结果如下:(1)从40条随机引物中筛选出9条引物,共获得93条谱带,多态率为58%;各采样点所得谱带平均为67条,其中Ⅰ站最少,为61条,Ⅴ站最多,为74条;(2)PCR-DGGE指纹图谱共含102条谱带,其中原核生物56条,真核生物46条,谱带总数以Ⅲ站、Ⅳ站和Ⅴ站较多,Ⅰ站和Ⅱ站较少;(3)5个采样点共观察到62种/类浮游生物,其中Ⅰ站和Ⅱ站种类较少,Ⅲ站、Ⅳ站和Ⅴ站种类较多,分布概率在100