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1.
对我国沿海5个自然群体长蛸的线粒体细胞色素氧化酶亚基I(COI)部分序列进行了测定和分析,经比对获得658bp核苷酸片段,其中碱基T、C、A和G的平均含量分别为37.02%、18.46%、30.15%和14.35%,AT的含量明显高于GC的含量。5个自然群体的长蛸中共发现18个变异位点,得到15个单倍型,包括4个共享单倍型,其中青岛群体的核苷酸差异数K以及平均核苷酸多样性指数Pi最高,烟台群体最低;群体间,青岛群体在群体间核苷酸差异数K、群体间平均每位点核苷酸替代数Dxy和群体间每位点净核苷酸替代数Da三个指标上都表现出比其它群体之间较高的水平,说明青岛群体具有最为丰富的遗传多样性。MEGA3.1软件计算5个群体间的Kimura2-paramter遗传距离,大连群体和青岛群体之间的遗传距离最远为0.0077,而大连群体与烟台群体之间的遗传距离最低,为0.0029。AMOVA分析表明,五群体间总遗传分化系数Fst=0.17410(P0.05),群体间遗传分化远小于群体内。NJ法和UPGMA法构建的分子进化树,5个地理群体的长蛸聚为两个族群,大连、烟台群体聚为一族群,青岛、连云港和舟山群体聚为另一族群。 相似文献
2.
以广东省珠海市外伶仃岛地区常见的4属5种石珊瑚为研究对象,对线粒体COI、16S rRNA和ITS三种基因片段数据进行分析,并计算了种间遗传距离。序列分析结果表明5种石珊瑚的COI、16S rRNA基因片段碱基AT含量大于GC含量,而ITS序列碱基AT含量小于GC含量;5种石珊瑚种间的三种基因平均遗传距离分别为0.043、0.134和0.763,所得遗传距离结果存在一定差异。将三种基因串联起来并利用邻位连接法(NJ)、最大似然法(ML)和最小进化法(ME)分别构建了分子系统树。在系统发育树中,科一级的系统进化关系与形态学分类一致,但蜂巢珊瑚科内的分子系统分类结果与形态学分类阐述的遗传进化关系略有差别,说明石珊瑚传统分类可能受骨骼可塑性的影响。研究结果为外伶仃岛石珊瑚的亲缘关系研究提供相关基础数据,并为该地区石珊瑚资源保护奠定理论基础。 相似文献
3.
环境样品的低生物量是微生物宏基因组学研究面临的首要挑战,通过基因组扩增技术来满足高通量测序对DNA样品量的需求是最常用的解决策略。MALBAC(Multiple Annealing and Looping Based Amplification Cycles)基因组扩增试剂盒最初为扩增和研究哺乳动物的单细胞基因组而研发。本文中,我们通过人工构建的微生物群落来检测该试剂盒在微生物宏基因组扩增方面的效率和应用可行性。结果表明,每个标准反应中,10 pg的DNA模板量足以满足MALBAC试剂盒对样品扩增的需要。每个标准反应DNA模板用量为10和100 pg时,所扩增DNA样品的基因组覆盖度与原始未扩增样品表现出高度的一致性,证明MALBAC试剂盒扩增效果的高度稳定性和一致性。常用的GenomePlex全基因组扩增试剂盒使我们可以在每个标准反应DNA模板量为100 pg的条件下扩增获得足够的DNA样品,但是结果表明该参照试剂盒无法有效的实现对群落中低丰度细菌菌株基因组的线性扩增。对于MALBAC试剂盒和参照试剂盒而言,在扩增高GC含量的微生物物种基因组DNA方面效率低下。我们的实验结果表明MALBAC试剂盒在高效扩增环境样品宏基因组DNA方面的可行性,但对该试剂盒在扩增环境样品中高GC含量微生物物种方面的适用性存在疑虑。 相似文献
4.
测定三疣梭子蟹(Portunus trituberculatus)9个个体COI基因部分序列467 bp,7个个体16S rRNA基因部分序列519 bp,同时测定样品蟹1个个体COI基因部分序列468 bp.结合GenBank中收集的梭子蟹科COJ,16S rRNA两个基因所有同源序列信息,使用Kimura双参数模型采用邻接法(NJ)、最大简约法(MP)构建梭子蟹科分子系统发育树;将样品蟹测得的COI基因序列和已知鲟属的其他蟹同源序列(429 bp)进行比对分析.结果分析表明:两个基因片段序列平均碱基AT数量分数都明显高于GC数量分数;梭子蟹属与美青蟹属关系最近,蟳属应为区别于梭子蟹属、美青蟹属、青蟹属的另一支,支持蟳属应划分在短桨蟹亚科的观点;根据遗传距离以及转换/颠换(R)值分析,判定出样品蟳为锐齿蟳.本试验运用线粒体基因片段探讨了梭子蟹类的系统发育关系以及样品蟹的种类鉴定,为线粒体基因片段在梭子蟹的物种鉴定和系统发育重建中的开发和利用提供重要参考. 相似文献
5.
胶州湾浮游桡足类18S核糖体RNA基因(18S rDNA)扩增及序列变异初步研究 总被引：3，自引：0，他引：3
采用PCR扩增、文库构建、限制性片段长度多态性分析、序列分析和系统学分析等方法，初步研究了夏季胶州湾上层海水浮游桡足类核糖体小亚基RNA基因(18S rDNA)约1．5kb片段的序列变异。从浮游生物混合DNA中选择性扩增桡足类18S rDNA，建立桡足类18S rDNA变异类型文库，并从文库中随机挑选的30个克隆进行分析。结果表明，Vsp Ⅰ限制性内切酶能将这些克隆分成频率分别为0．17、0．23和0．6的3种操作分类单元(OTUs)，遗传多样性指数达到0．95。3条OTU代表克隆序列与甲壳纲桡足亚纲核苷酸差异数在75．4—97．8之间，而与其他亚纲的差异都高于100。3条OTU代表克隆序列均属于桡足亚纲，其中，AY437861和AY437862属于哲水蚤目。3条OTU代表克隆序列可分为2个高变异区和3个相对保守区，其GC％分别为47．37％、48．16％和48．57％。研究结果表明，混合DNA提取方法简单，设计的引物可选择性地扩增浮游桡足类18S rDNA，根据18S rDNA序列序列变异描述浮游桡足类多样性是可行的。研究结果也为在浮游桡足类分类中引入18S rDNA序列奠定了基础。 相似文献
6.
中国对虾微卫星DNA的筛选 总被引：35，自引：5，他引：35
于2000年2月以中国科学院海洋研究所水族楼暂养的中国虾对材料，采用常规方法从尾部肌肉中提取DNA，构建小片段部分基因组文章，采用人工设计合成的（CT）7，（AT）7重复征段作引物，利用RCR法对中国对虾小片段部分基因组文库进行筛,一实验首冼 对中国对虾中获得31个微卫星序列，分别分析于18个阳性重组克隆中，其中perfect共23个，占74％，imperfect2个，占7％，compound perfect1个，占3％，compound imperfect5个，占16％，结果还表明，在中国对虾基因组DNA中，（CT）n,(AT)n)形式的微卫星序列的含量非常丰富。 相似文献
7.
Peter Goldfarb J.Andy Spry Deborah Dunn David Livingstone Alan Wiseman G.Gordon Gibson 《Marine environmental research》1989,28(1-4)
In this study we have used cloned gene probes for human glutathione peroxidase (GPX), rat cytochrome P-450IVA1 and rat cytochrome P-450IIE1 to detect homologous sequences in RNA from the hepato-pancreas of Mytilus edulis. The presence of sequences hybridising to the GPX and P-450IVA1 probes, but not to the P-450IIE1 probe, confirms the ancient origin of the former genes and indicates that conserved-sequence DNA probes from higher organisms can be used to examine the structure and function of genes of environmental interest in marine organisms. 相似文献
8.
提供一个关于截断误差使简单系统复杂化的直接实验证据,以此证明存在混沌抗退化机理.分别构造了一个一维圆弧迭代系统和一个一维抛物线迭代系统,两者均有一个非双曲不动点,其迭代序列被证明是简单极限序列,数字计算实验显示这两个迭代系统都存在可以越过不动点的序列.采用计算"元胞"分析方法清晰地展示了截断误差导致非双曲不动点邻域拓扑变异:形成第I类阵发混沌通道,或产生纹波分岔. 相似文献
9.
《Marine and Petroleum Geology》2003,20(2):111-128
Some global estimates suggest that gas hydrates represent the largest reservoir of fossil fuel. However, only a few studies of the resource and economic potential of individual gas hydrate accumulations exist. Here we estimate the volume of hydrate-bound gas at GC (Green Canyon) blocks 184/185, GC 234/235, GB (Garden Banks) 388, MC (Mississippi Canyon) 798/842, GC 204, MC 852/853, and AT (Atwater Valley) 425/426 sites in the Gulf of Mexico at water depths ∼500–2000 m. The structural accumulations may contain from 4.7×108 to 1.3×1011 m3 of gas at standard temperature and pressure. The resources in individual gas hydrate accumulations are comparable (by volume) with the reserves in very small to major conventional gas fields. Various geologic, technologic, and economic factors affect the economic potential of studied accumulations. The MC 852/853 appears to be characterized by the most favorable combination of these factors, and thus is suggested to have the highest economic potential. The economic potential of gas hydrate accumulations at GC 204, GB 388, and AT 425/426 sites is ranked as ‘average’. Gas hydrate accumulations at GC 234/235, GC 184/185, and MC 798/842 sites contain only small volumes of hydrate-bound gas, and likely have no economic potential. Future gas hydrate research should focus on the detailed study of large structural gas hydrate accumulations from which gas may be profitably recovered (e.g. the MC 852/853 site). 相似文献
10.
骨条藻(Skeletonema)隶属于硅藻门(Bacillariophyta),是一种分布广泛的广温广盐性藻类,也是我国沿海常见的赤潮生物之一。为确定北部湾涠洲岛5株骨条藻的分类地位,采用PCR克隆了这5株骨条藻核糖体的大亚基基因(LSU)和内转录间隔区(ITS)序列。通过与GenBank数据库中骨条藻属的LSU、ITS序列进行比对,得出的结果一致:5株涠洲岛骨条藻均为热带骨条藻(Skeletonema tropicum)。本研究运用分子标记法,首次确定了北部湾涠洲岛海域存在有热带骨条藻,结果可为涠洲岛与广西北部湾海域浮游植物多样性、赤潮生物组成及赤潮的预警与有效防治提供科学依据。 相似文献
11.
测定了褶痕相手蟹(Sesarma plicata)和红螯相手蟹(S.haematocheir)线粒体细胞色素氧化酶I亚基(COI)基因片段的序列,其长度均为658bp,A,T,G,C的平均含量分别为28.6%,37.5%,17.0%,16.9%和29.5%,39.0%,16.2%,15.3%。2种蟹共出现5种单倍型,褶痕相手蟹2种,红螯相手蟹3种。两种间有75个(11.4%)多态性核苷酸位点,其中转换42个,颠换33个;种间差异远大于种内个体间差异。2种相手蟹的AT含量明显高于GC含量,这与其它海产甲壳动物COI基因研究结果相似。 相似文献
12.
王福来 《海洋学报(英文版)》2010,29(9)
A specific uniform map is constructed as a homeomorphism mapping chaotic time series into [0,1] to obtain sequences of standard uniform distribution. With the uniform map, a chaotic orbit and a sequence orbit obtained are topologically equivalent to each other so the map can preserve the most dynamic properties of chaotic systems such as permutation entropy. Based on the uniform map, a universal algorithm to generate pseudo random numbers is proposed and the pseudo random series is tested to follow the standard 0-1 random distribution both theoretically and experimentally. The algorithm is not complex, which does not impose high requirement on computer hard ware and thus computation speed is fast. The method not only extends the parameter spaces but also avoids the drawback of small function space caused by constraints on chaotic maps used to generate pseudo random numbers. The algorithm can be applied to any chaotic system and can produce pseudo random sequence of high quality, thus can be a good universal pseudo random number generator. 相似文献
13.
High-resolution shallow seismic-reflection profiles obtained from the western Mersin Bay have revealed the existence of the two distinct depositional sequences (C and B) lying on a narrow and relatively steeply-sloping continental shelf which mainly receives its sediments from the ephemeral rivers. The upper Holocene sedimentary sequence (C) is characterized by stratified (simple to complex) to chaotic reflection configurations produced by the development of a prograding wedge of terrigenous sediment. Particular occurrences of slope- and front-fill facies and the lack of a sharp boundary, which has, however, been observed on the western shelf of this bay, between the Early Holocene and latest Pleistocene deposits are related to possible movement of underlying deposits due to local gravity mass movements or synsedimentary tectonics due to adjustment of the underlying evaporites in adjacent basin. The maximum thickness of the topmost sequence C is associated with the Tarsus–Seyhan delta, which lies to the northeast of the area and is prograding along the shelf. Other variations in thickness (5–40 m) of this topmost sequence are related to the variable sediment discharge along the coast, and the distance from the coast. It is at a maximum (40 m) in the nearshore area just west of the Lamas river mouth and at a minimum (5–15 m) in the offshore area.
The lower depositional pre-Holocene sequence (B) is characterized by continuous to wavy reflection configurations and how some cyclicity, suggesting coarse, heterogeneous sediments deposited under high energy conditions (fan-deltas) of Plio-Pleistocene age.
The combined interpretation of seismic reflection profiles with the available bore-hole data reveals the existence of a widespread Miocene acoustic basement (A) off the Susanoğlu–Tırtar coasts and Karapınar–Gilindirez rivers mouths. Unusual features in some profiles suggest the escape of coastal freshwater into the accumulating sediment. 相似文献
14.
Gerald McMahon L.Julie Huber John J Stegeman Gerald N Wogan 《Marine environmental research》1988,24(1-4)
It has been shown that a high incidence of hepatomas are present in winter flounder (Pseudopleuronectes americanus) obtained from Boston Harbor. It has been suggested that this may be a consequence of locally high levels of polycyclic aromatic hydrocarbons found in the sediment. The purpose of this study was to determine whether transforming DNA sequences (oncogenes) could be identified in liver neoplasms isolated from feral fish and to study their relationship to their corresponding proto-oncogenes. The ultimate aim of this study is to characterize novel mutations in oncogenes derived from these hepatomas to correlate these genetic changes with chemical exposure history. Genomic DNA was isolated from liver neoplasms and transfected into NIH3T3 mouse fibroblasts to assay for the formation of transformed foci. DNA was prepared from transformed foci and analyzed by Southern blot hybridization to viral DNA probes specific for c-Ki-ras and c-Ha-ras DNA sequences. A c-Ki-ras oncogene was identified in a transformant derived from one of the two tumors assayed. Comparison of c-Ki-ras DNA sequences of tumor and tumor-derived transformants indicate that the activated oncogene in the transformant is of flounder origin. We are currently analyzing the flounder oncogene for activating point mutations by primer-directed enzymatic amplification and direct sequence analysis. 相似文献
15.
Intrastratal deformation of marine strata is ordinarily recorded in high-resolution seismic reflection profiles as acoustically transparent or chaotic intervals marked by hyperbolic echoes. Intrastratal deformation is easily confused with buried slump or slide deposits formed initially at the sea floor. Correct identification of intrastratal deformation depends on the presence of a warped continuously reflective layer overlying a chaotic/transparent layer. Decollement is the key criterion for identification in seismic reflection profiles. Other criteria include intrusive structures or faults rooted in a chaotic/transparent layer and thickening and thinning of a chaotic/transparent layer with transitions to reflective intervals. 相似文献
16.
对长达70.20m的东海浅钻EY02-1进行了岩石磁学和古地磁分析,证明沉积物的载磁矿物主要为低矫顽力的磁铁矿,磁性地层揭示了发生于9.62~8.58m的磁极性事件,结合钻孔上部的AMS14C测年证明它为全新世初期的哥德堡磁极性漂移,线性外推的时间是距今12681~10206Ma,为全新世开始时地磁场是否发生过短期的磁极性漂移提供了新证据;与东海高分辨率的浅地层地震剖面以及典型钻孔(中法联合东海地震调查和DZQ4钻孔)对比还揭示,在中更新世地层中也出现过两次磁倾角变化。在钻孔中下部54.00~50.94m(2271—2151号样品)出现一段磁倾角变小甚至变成负值,但是由于该段沉积物以粗颗粒的砂为主并且负向样品并不连续,依据研究的标准不作为反磁极性事件。第二个比较连续的负向样品段出现在最底部70.20~64.31m。虽然研究区域内不乏揭示中更新统地层的地震剖面,但至今没有足够长的钻孔在时间上予以佐证。根据东海地震相对比和沉积物中海侵和海退旋回的不同特征以及布容期以来报道的反磁极性事件发生的时间来推测下部地层的时代归属。由于钻孔最底部的沉积主要是粗颗粒的粉砂质砂和细砂,同时钻孔也穿透了倒数第二冰期的杂乱地震相地层和其下的平行透明海相层,所以推测下部的倒转可能为发生在MIS8晚期的CR0反磁极性事件(距今265~255ka)。 相似文献
17.
Paul Weimer 《Geo-Marine Letters》1989,9(4):185-272
The Mississippi Fan is a large, mud-dominated submarine fan over 4 km thick, deposited in the deep Gulf of Mexico during the
late Pliocene and Pleistocene. Analysis of 19,000 km of multifold seismic data defined 17 seismic sequences, each characterized
by channel, levee, and associated overbank deposits, as well as mass transport deposits. At the base of nine sequences are
a series of seismic facies consisting of mounded, hummocky, chaotic, and subparallel reflections, which constitute 10–20%
of the sediments in each the sequences. These facies are externally mounded and occur in two general regions of the fan: (1)
in the upper and middle fan they are elongate in shape and mimic the channel's distribution; (2) in the middle fan to lower
fan they are characterized by a fan-shaped distribution, increasing in width downfan. These facies are interpreted to have
formed as disorganized slides, debris flows, and turbidites (informally called “mass transport complexes”).
Overlying this basal interval, characteristic of all sequences, are well-developed channel-levee systems that constitute 80–90%
of the fan's sediments. Channels consist of high amplitude, subparallel reflections, whereas the flanking levee sediments
appear as subparallel reflections that have high amplitudes at the base changing upward to low amplitude. The vertical change
in amplitude may reflect a decrease in grain size and bed thicknesses. Overbank sediments are characterized by interbedded
subparallel to hummocky and mounded reflections, suggesting both turbidites from the channel, as well as slides and debris
flows derived both locally and from the slope updip. 相似文献
18.
中国沿海常见蜑螺科贝类的DNA条形码 总被引：1，自引：0，他引：1
DNA条形码不仅为物种鉴定提供了有效方法,而且也有助于分类学和生物多样性研究。本研究旨在探讨将COI和16S rRNA基因序列应用于中国沿海蜑螺科贝类物种鉴定的可行性,获得了该科3属7种贝类61个个体的COI和16S rRNA基因序列。基于COI基因序列的种内遗传距离为0.00—1.29%,平均为0.67%;属内种间遗传距离为4.62%—19.25%,平均为13.02%;基于16S rRNA基因序列的种内遗传距离为0.00%—0.48%,平均为0.23%;属内种间遗传距离为2.47%—8.48%,平均为6.37%。两种基因序列在所研究的蜑螺中,种内遗传差异均小于种间遗传差异,存在明显的条形码间隙,所有物种在系统发生树上都表现为独立的单系群。结果表明,线粒体COI和16S rRNA基因序列可以作为DNA条形码标准基因对蜑螺科贝类进行有效地物种鉴定。 相似文献
19.
南海中部地震反射波特征及其地质解释 总被引：8，自引：2，他引：6
20世纪70年代以来,在南海中部海区开展了各种地震调查,为研究盖层和基底发育、断裂和岩浆活动、海盆成生演化提供了重要依据。在对南海中部海区4112km48道反射地震资料解释的基础上,识别出了T1,T2,T4,T6,Tg等五个反射界面;识别出了I～V五套地震反射层组,推测时代分别为上新世-第四纪、中新世晚期、中新世早-中期、渐新世和前渐新世。层组I～Ⅱ全区广布。在陆坡、岛坡区,层组Ⅲ以下层组主要见于断陷中;在深海盆,层组Ⅲ分布仍较广,除了在深海盆北段见到层组Ⅳ外,在西南次海盆剖面两缘也见到该层组。在东部次海盆剖面中还不同程度见到了双程反射时间为8.4～8.7s的莫霍面反射,埋深为10～12km,地壳厚度为6～8km.西南次海盆水深和新生界基底埋深均比深海盆北段除外的东部次海盆深,分别为4000-4300和5200～5500m.根据年龄和基底深度关系经验公式,计算西南次海盆基底年龄为距今51～39Ma.地震反射层组解释和年龄一基底深度关系计算表明,西南次海盆形成并非晚于东部次海盆,而是同时或早于东部次海盆。 相似文献
20.
根据已知的β-胡萝卜素酮化酶(β-carotene ketolase,BKT)的cDNA序列设计引物,利用长距离PCR扩增获得了bkt基因的cDNA完整编码片段及基因组DNA片段,并对这些片断进行了序列测定。cDNA和基因组DNA比对结果表明该基因至少包括5个内含子,它们的剪切位点皆符合GU-AG规律。在比对结果中同时还发现一个19bp的短序列重复,该重复序列在bkt的cDNA和基因组DNA上都发生了多次重复,推测在BKT的表达调控中可能具有一定功能。另外,在序列比对过程中还发现本实验所获得的cDNA和基因组DNA序列与前人报道的cDNA序列之间都存在多处单碱基差异和19bp的短序列差异。 相似文献