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1.
The genetic structure of the exotic ascidian Styela plicata (Tunicata) from Italian ports,with a re‐appraisal of its worldwide genetic pattern 
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下载免费PDF全文 Ferruccio Maltagliati Lisa Lupi Alberto Castelli Federica G. Pannacciulli 《Marine Ecology》2016,37(3):492-502
The pleated ascidian Styela plicata (Lesueur, 1823) is a solitary species commonly found in ports and marinas around the world. It has been recorded in the Mediterranean region since the mid‐19th century. In the present work, the species’ genetic diversity was analysed, employing a 613‐bp portion of the mitochondrial cytochrome c oxidase subunit I (COI) gene from 149 individuals collected in 14 ports along Italian coasts at spatial scales ranging from 1 to approximately 2200 km. Haplotype and nucleotide diversity values were h = 0–0.933 (total h = 0.789) and π = 0–0.145 (total π = 0.0094), respectively. A general southward trend of increasing within‐population genetic diversity was observed. Analysis of molecular variance revealed significant genetic structuring but no significant differences were detected among basins, and no isolation by distance was found. Our data were integrated with the COI sequences available from previous studies and re‐analysed in order to investigate the possible routes of introduction of this ascidian into the Mediterranean Sea. The presence of the two COI haplogroups detected in previous molecular investigations on S. plicata at intercontinental spatial scale was confirmed in the Mediterranean Sea. The results revealed multiple introductions of S. plicata, although some locations appear to have experienced rapid expansion from few founding individuals with reduced genetic diversity. However, continuous introductions would confound the pattern deriving from single founder events and make it difficult to estimate the time needed for gene diffusion into established populations. This mixing of effects creates difficulties in understanding the past and current dynamics of this introduction, and managing this alien invasive ascidian whose genetic structure is continuously shuffled by vessel‐mediated transport. 相似文献
2.
Comparative phylogeography and population genetic structure of three widespread mollusc species in the Mediterranean and near Atlantic 下载免费PDF全文
下载免费PDF全文 Although several studies have evaluated the genetic structure and phylogeographic patterns in many species of marine invertebrates, a general model that applies to all of them remains elusive. For example, some species present an admixture of populations with high gene flow, whereas others exhibit more complex patterns characterized by small‐scale unstructured genetic heterogeneity, even at a local scale. These differences are thought to be due to clear biological aspects such as direct versus indirect development, or the presence of lecithotrophic versus planktotrophic larvae, but few studies compare animals with similar distributions and life modes. Here, we explore the phylogeographic and genetic structure patterns in two chiton (Chiton olivaceus and Lepidopleurus cajetanus) and one abalone (Haliotis tuberculata) species co‐occurring in the same habitat. Samples were obtained from shallow rocky bottoms along the Iberian Peninsula (Atlantic and Mediterranean coasts), Italy, Croatia and Greece, and the mitochondrial markers COI and 16S rRNA gene were sequenced. Our data show evidence of admixture and population expansion in C. olivaceus and H. tuberculata, whereas L. cajetanus exhibited a ‘chaotic patchiness’ pattern defined by a high genetic variability with locality‐exclusive haplotypes, high genetic divergence, and a lack of geographic structure. Shared haplotypes were sampled in both coasts of Iberia (for H. tuberculata) and in the Western and Eastern Mediterranean (for C. olivaceus), potentially indicating high dispersal ability and a recent expansion. The processes underlying the fine‐scale structuring in L. cajetanus remain a mystery. These results are especially interesting because the reproductive mode of the two chitons is similar but differs from that of the abalone, with a veliger larva, while instead the genetic structure of C. olivaceus and H. tuberculata are similar, thus contrasting with predictions based on the life history of the three molluscs and showing that the genetic patterns of marine species may be shaped by many factors, including historical ones. 相似文献
3.
Ben Othmen Abdelwahe Abhary Mohame Deli Temim Ouanes Zouhour Alhuwaiti Nour Dimassi Najet Mansour Lamjed 《海洋学报(英文版)》2020,39(2):28-37
The present investigation focuses on population genetic structure analysis of the endangered giant clam species Tridacna maxima across part of the Red Sea,with the main aim of assessing the influence of postulated potential barriers to gene flow(i.e.,particular oceanographic features and marked environmental heterogeneity)on genetic connectivity among populations of this poorly dispersive bivalve species.For this purpose,a total of 44 specimens of T.maxima were collected from five sampling locations along the Saudi Arabian coast and examined for genetic variability at the considerably variable mitochondrial gene cytochrome c oxidase I(COI).Our results revealed lack of population subdivision and phylogeographic structure across the surveyed geographic spectrum,suggesting that neither the short pelagic larval dispersal nor the various postulated barriers to gene flow in the Red Sea can trigger the onset of marked genetic differentiation in T.maxima.Furthermore,the discerned shallow COI haplotype genealogy(exhibiting high haplotype diversity and low nucleotide diversity),associated with recent demographic and spatial expansion events,can be considered as residual effect of a recent evolutionary history of the species in the Red Sea. 相似文献
4.
Molecular data have shown that jellyfishes are more geographically restricted and evolutionarily divergent than previously thought. We examined genetic variation and divergence within the meroplanktonic barrel jellyfish Rhizostoma pulmo in the Mediterranean Sea; specific sampling areas were the northern Adriatic, western Mediterranean and Tunisian coast. A total of 19 sampling sites and 68 sequences of the mtDNA cytochrome c oxidase subunit I (COI) gene were used. Of the 68 COI sequences, 45 were newly collected specimens which originated from nine sampling sites along the Tunisian coast. A total of 24 haplotypes were obtained and the specimens sampled were characterised by relatively high levels of haplotype diversity (h = 0.866) and low levels of nucleotide diversity (π = 0.004). Haplotype network analysis showed the presence of three distinct phylogenetic lineages (populations), with separate geographic ranges in the northern Adriatic, western Mediterranean and Tunisian coast. The observed genetic differentiation between these three lineages was supported by the presence of significant genetic differentiation between the 19 populations (FST = 0.757, p < 0.001). The high level of genetic differentiation detected in the barrel jellyfish investigated could be attributed to either intrinsic and/or extrinsic barriers to genetic exchange between different populations that may have adapted to different environmental conditions. 相似文献
5.
采用16S rRNA基因测序技术,对我国东南沿海4个地理群体的厚壳贻贝遗传结构及遗传变异进行研究。通过对4个厚壳贻贝群体共83个个体的线粒体16S rRNA基因进行测序,获得1个长度为305bp的同源序列,共检测到150个多态位点,多态位点比例达49.18%。83个个体中共检测到28个单倍型,单倍型多样性指数(Hd)为0.810,核苷酸多样性指数(Pi)为0.09602,平均核苷酸差异数(K)达27.846。结果表明,我国东南沿海厚壳贻贝群体具有较高的遗传多样性水平。遗传结构检测结果表明,舟山群体、温州群体、宁德群体间的遗传距离小,遗传分化系数(Fst)为-0.0141—0.0059之间,群体内部无显著分化(P>0.05),而福州群体与其它群体间遗传距离较大,为0.215—0.217之间,遗传分化系数(Fst)也较大,为0.6217—0.6319之间,存在极显著的遗传分化(P<0.001)。 相似文献
6.
Rim Ladhar‐Chaabouni Amel Hamza‐Chaffai Yann Hardivillier Benoît Chénais Françoise Denis 《Marine Ecology》2010,31(2):355-363
The internal transcribed spacer 1 (ITS1) region of 29 individuals of Cerastoderma glaucum (from the Mediterranean Sea, the Atlantic and the North Sea) and 18 individuals of Cerastoderma edule (from the Atlantic and the North Sea) and the cytochrome c oxidase subunit I (COI) region of 43 individuals of C. glaucum (from the Mediterranean Sea, the Atlantic and the North Sea) and 9 individuals of C. edule (from the Atlantic and the North Sea) were PCR amplified and sequenced. The ITS1 sequences led us to describe 27 genetic haplotypes, while 21 genetic haplotypes were determined via the COI sequences. The ITS1 and the COI sequences revealed an important genetic variability within the Mediterranean population of C. glaucum, which contained two different phenotypes: orange foot and yellow foot. A genetic differentiation between the two phenotypes was revealed by the nucleotide diversity index (π) and is strengthened by the AMOVA analysis. This result leads us to suspect the presence of two different groups in the same population of C. glaucum. Nevertheless to be confirmed this hypothesis requires further studies using more locations and a larger number of sample sizes. 相似文献
7.
Joana M da Silva Antonina dos Santos Marina R Cunha Filipe O Costa Simon Creer Gary R Carvalho 《Marine Ecology》2013,34(2):157-170
Despite the high number of species and ecological diversity of pandalid shrimps, there has been no previous attempt to resolve evolutionary relationships of several genera using molecular tools. Although mitochondrial DNA cytochrome oxidase I (COI) is widely used in barcoding studies to delimit species boundaries, additional insights into phylogenetic affinities can be obtained, especially when used in combination with data from additional genes. The knowledge of molecular diversity is essential to understand phylogenetic relationships and will help systematic clarifications. Based on partial fragments of the 16S and COI genes, we have focused specifically on addressing the systematic relationships of the economically and ecologically important shrimp genus Plesionika within a framework of five genera from within the Pandalidae. Our results showed that species within Plesionika are substantially divergent when compared with other genera, exhibiting the highest average nucleotide divergence, with 0.1123 and 0.0846 in COI and 16S genes, respectively. In addition, sequence divergence was found to vary greatly within the genus Plesionika (COI/16S): 0.0247/0.0016 between Plesionika antigai and Plesionika heterocarpus and 0.1616/0.098 between Plesionika heterocarpus and Plesionika edwardsii. We did not find amino acid sequence divergence between P. heterocarpus and P. antigai compared with P. heterocarpus and P. edwardsii (8.10%, K2P distance). Three species of Plesionika (P. antigai, P. heterocarpus and Plesionika scopifera) appear well separated from other Plesionika species in both maximum likelihood and Bayesian analyses. The present study confirms the utility of COI over 16S as a genetic marker to resolve relationships between different species of Plesionika from the Northeast Atlantic and Mediterranean Sea, in addition to species delimitation. The findings highlight the need to further review paraphyly within Plesionika in an attempt to recognize a concordance in the evolutionary history of Plesionika with major ecological and geological events. 相似文献
8.
由于近年来过度捕捞及滩涂开发,野生矛尾复虾虎鱼资源量急剧下降.因此,对我国矛尾复虾虎鱼开展遗传多样性研究,有利于掌握矛尾复虾虎鱼种质资源现状.本文基于线粒体COI序列对大连、如东、连云港、长江口和宁波的5个矛尾复虾虎鱼群体开展了遗传多样性研究.结果 表明,5个群体中共有17个单倍型,在427个位点中,共检测到15个变异位点,其中简约信息位点11个,单独位点4个.碱基A、T、G、C的平均含量分别为24.6％、29.6％、20.1％、25.7％.5个群体的单倍型多样性和核苷酸多样性分别为0652和000255.野生矛尾复虾虎鱼整体的遗传多样性水平为中等偏下,宁波群体的遗传多样性最高,如东群体最低.群体间遗传分化系数FST及遗传距离分析表明,宁波群体与其他群体遗传距离相对较远,并存在显著的遗传分化;AMOVA分析表明,群体内的遗传变异高于群体间变异(81.45％＞ 18.55％);中性检验结果显示,大连、连云港、长江群体在历史上可能经历过扩张.本研究为野生矛尾复虾虎鱼种质资源保护和合理开发利用提供了理论依据. 相似文献
9.
带鱼(Trichiurusjaponicus)是广泛分布于东亚大陆架海域的暖温性近底层经济鱼类,也是东海区最重要的海洋渔业捕捞对象。然而,目前的研究报道对东海近岸带鱼群体遗传变异特性认识不足,不利于其种群的遗传资源保护和管理。本研究利用线粒体控制区序列对东海近岸带鱼6个群体191个个体的遗传多样性、遗传分化和历史动态进行分析。在577 bp长的控制区序列中共检测到70个多态位点,定义了121个单倍型。群体总的单倍型多样性较高(0.9911),但总的核苷酸多样性较低(0.0092),群体间遗传多样性水平差异较小。单倍型遗传学关系、Fst值和分子方差分析结果均表明群体间的遗传分化不显著,存在广泛的基因交流。历史动态分析结果表明东海近岸带鱼群体在更新世中晚期可能经历了瓶颈效应和随后的群体快速扩张,这是导致群体遗传多样性较低的主要原因。带鱼较强的扩散能力、洄游行为、海洋环流以及近期的群体扩张可能是造成东海近岸带鱼缺乏显著的系统地理种群结构的原因。研究结果提示,在线粒体DNA水平上,东海近岸带鱼群体是一个随机交配的种群,在遗传资源管理上可作为一个单元进行管理。 相似文献
10.
Population genetic structure and historical demography of Chinese horseshoe crab (T. tridentatus) along southeast coast of China were inferred from the sequence data of mitochondrial cytochrome c oxidase subunit I (COI) fragment. The sequence analysis for 964 bp COI fragment was conducted in 28 individuals collected from five localities: Ninghai in Zhejiang Province, Meizhou and Zhangpu in Fujian Province, Beihai of Guangxi Zhuang Autonomous Region and Danzhou of Hainan Province. Sequence variation was relatively low with a total of seven transitions observed. In all localities, Haplotype H3 was the dominant type observed among eight haplotypes defined previously, and was at the center of radiation in Median-Joining network. The prolonged star-like network suggests a signature of population expansions. The level of diversity was low in total, with haplotype diversity (Hd) being equal to 0.765 and nucleotide diversity (π) being equal to 0.001 18, respectively. The genetic structure analysis revealed the significant genetic difference between Ninghai and Danzhou populations. Both mismatch distribution analysis and Fu's Fs test provided consistent inference of historic population expansion. The low genetic diversity of horseshoe crab observed along China coast indicated that urgent measures should be taken to protect this rare marine animal. 相似文献
11.
中国沿海不同地区泥蚶(Tegillarca granosa)的遗传多样性分析 总被引：1，自引：0，他引：1
以采自海南海口、广西防城港、广西北海、广东湛江、福建漳州、山东荣成、山东威海7个地理群体62个泥蚶个体为材料,获取592bp线粒体COI基因片段序列,并进行遗传多样性及分化分析。多态性遗传参数统计显示:62个个体共检测出103个多态性位点,定义了26个单倍型;总群体单倍型多样性指数为0.834,核苷酸多样性指数为0.01665,平均核苷酸差异数为9.85772。7个群体均显示出较丰富的遗传多样性,群体内遗传距离及群体内遗传多样性参数显示中国沿海泥蚶遗传多样性由北向南呈升高趋势,而群体内遗传分化系数也呈现升高的趋势。基于26个单倍型COI序列构建的NJ树和UPGMA树以及基于群体间遗传距离构建的UPGMA树显示,荣成群体和威海群体亲缘关系较近,聚成一小支,而后与漳州群体相聚,然而南方类群并没有聚为独立的一支。 相似文献
12.
为了研究我国南部沿海近亲拟相手蟹(Parasesarma affine)的群体遗传结构,本研究对12个地理群体共222个个体的线粒体DNA的细胞色素氧化酶亚基Ⅰ (COⅠ)基因片段进行了分析。结果表明,612 bp的COⅠ基因片段检测到34个变异位点,共定义了40个单倍型,其中Hap2为12个群体的共享单倍型,占个体总数的69.81%。总群体的单倍型多样性水平Hd为0.508 9,核苷酸多样性水平Pi为0.001 126,表现出中等水平的Hd和低水平的Pi。单倍型邻接发育树和单倍型中介网络图没有形成明显的地理系谱结构。近亲拟相手蟹群体内的遗传距离为0.000 36～0.001 73,群体间的遗传距离为0.000 48～0.001 72。群体间的遗传分化系数(Fst)和分子方差分析(AMOVA)结果表明,近亲拟相手蟹群体遗传分化水平低,其变异主要来自群体内。中性检验和核苷酸不配对分布结果提示,近亲拟相手蟹近期经历了群体扩张事件,扩张时间大约发生于5.1万年前的更新世晚期。研究表明,较长的幼虫浮游期以及海洋环境中缺少影响群体扩散的屏障可能是近亲拟相手蟹各地理群体间能进行广泛的基因交流,从而表现出较低的遗传分化水平的重要原因,更新世的剧烈气候变迁亦可能对其群体的遗传结构和分布格局产生影响。研究结果为近亲拟相手蟹自然资源的保护及合理开发利用提供了一定理论依据。 相似文献
13.
对2 组光倒刺鲃(Spinibarbus hollandi)杂交子一代(长江♀×北江♂子一代, 北江♀×长江♂子 一代)及其亲本(北江♀、♂, 长江♀、♂)的线粒体COI 基因序列进行了分析。在18 个样品中共检测到 8 个单倍型和35 个核苷酸多态位点。通过序列差异分析和遗传距离比较发现, 核苷酸序列同源性在 98.1%-99.9%之间, 遗传分化不明显。杂交子一代的5 个单倍型与其母本的2 个单倍型的核苷酸同 源性在99.4%-99.8%之间。而与父本的同源性分别为98.5%、98.2%、98.2%、98.4%、98.1%.实验 结果表明两种杂交子一代的线粒体 COI 基因严格遵循母性遗传规律。 相似文献
14.
密斑马面鲀Thamnaconustessellatus是在我国南海海域较为常见的一种马面鲀属鱼类。本研究基于线粒体DNA控制区序列对南沙群岛密斑马面鲀3个群体的遗传结构及其遗传多样性进行了分析。研究结果显示,密斑马面鲀的控制区序列变异程度较大,86尾个体序列的变异位点数为38个,共定义了28个单倍型;3个密斑马面鲀群体的单倍型多样度和核苷酸多样度均较高,且相差不大;密斑马面鲀群体间未检测到显著的群体遗传结构,分子方差分析表明,99.67%的遗传差异来自于群体内,群体间遗传差异仅为0.33%。贝叶斯树和最大似然树均显示出密斑马面鲀单倍型间松散的分布,未检测到显著的谱系结构。群体历史动态分析结果表明密斑马面鲀的群体经历了更新世的群体扩张事件。 相似文献
15.
对我国沿海地区10个菲律宾蛤仔野生群体线粒体16S r RNA和COI基因部分序列进行测序,分别得到了长度为473bp和632bp的片段。结果表明,16S r RNA 193条序列A+T平均含量为66.6%,共检测到21个变异位点,193个个体具有22种单倍型;COI基因183条序列A+T平均含量为64.8%,共检测到126个变异位点,183个个体具有67种单倍型。基于群体间遗传距离利用Mega5.1软件构建10个群体的NJ树,聚类结果表明,大连群体和荣成群体聚为一支,其余8个群体聚为一支。AMOVA分析表明,大连群体和荣成群体间分化不显著,而荣成、大连群体与其余8个群体间的分化达到极显著水平(P0.01),说明我国沿海的菲律宾蛤仔野生群体存在一定的遗传分化。 相似文献
16.
Planktonic copepod Calanus sinicus is the dominant meso-zooplankton in the Northwest Pacific Ocean. To better understand its population dynamics and phylogeographic patterns, 243 C. sinicus individuals were collected from seven locations across the shelf waters of China and its population genetics was studied by mitochondrial DNA cytochrome oxidase I(mtCOI) sequences analyses. Thirty-nine different sequences, or haplotypes, were detected with moderate haplotype diversity(h=0.749) and low nucleotide diversity(π=0.003) for all populations. The evolutionary divergence between geographic populations varied from 0.24% to 0.37%, indicative of very limited genetic differentiation. Visualized minimum spanning network(MSN) and phylogenetic analysis of all the detected haplotypes did not reveal any clear phylogeographic pattern. Furthermore, AMOVA data showed no significant spatial population differentiation existed among the individuals collected across China shelf waters. Pairwise FST values showed that population collected from northwest of the East China Sea(ECS) displayed a low difference to other populations. Mismatch distribution analyses and neutrality tests indicated that C. sinicus might undergo a demographic/population expansion. No significant population genetic structuring was detected, indicating an extensive gene flow among the C. sinicus populations. Our results provide molecular evidence for the hypothesis that C. sinicus in the northwestern South China Sea in winter is transported from the East China Sea and the Yellow Sea by the China Coastal Current during the northeast monsoon period. 相似文献
17.
利用线粒体DNA细胞色素氧化酶亚基(COI)基因序列片段对江浙闵沿海地区缢蛏三个野生群体(江苏射阳-WS、浙江象山-WX,福建霞浦-WP)和三个养殖群体(江苏射阳-CS、浙江象山-CX、福建焦城-CJ)的遗传结构进行初步分析.以特异引物进行PCR扩增,经纯化、测序、同源序列比对获得长度为556bp的核苷酸序列,其中A+T含量为66.2%,显著高于G+C含量.在缢蛏六群体98个个体中共检测到了56个单倍型和66个核苷酸多态位点,多态位点比例为11.7%.野生群体的平均核苷酸差异数和核苷酸多样性指数略高于养殖群体,但是野生群体和养殖群体的单倍型多态性指数均大于0.9,其单倍型较为丰富.此外,六群体均有各自特有的单倍型,但只有射阳野生群体与其他群体无共享单倍型,具有鉴定该群体的特异碱基序列.遗传距离和聚类结果显示,养殖群体与象山野生群体和霞浦野生群体间亲缘关系较近. 相似文献
18.
本研究利用形态学方法和基于线粒体细胞色素氧化酶亚基Ⅰ(COⅠ)的遗传学方法分析了中国沿海青蚶(Barbatia virescens)6个地理群体的形态差异、遗传多样性、遗传结构及其种群历史动态。单因素方差分析(ANOVA)和Tukey检验表明,青蚶不同地理种群间表现出显著形态差异(P0.05)。经PCR扩增测序获得长度为587bp的COⅠ基因片段,112个个体共检测到18个多态性位点、17个单倍型,每个群体均有特有单倍型。青蚶群体的遗传多样性水平较低,总群体的平均单倍型多样度为0.5472,平均核苷酸多样度为0.000974。AMOVA分析表明,群体内个体间的遗传分化是青蚶群体遗传变异的主要原因,占87.40%。阳江群体与其他群体之间存在显著的低程度的遗传分化,而其他群体间的遗传分化不显著。单倍型网络关系图呈典型的星状拓扑结构,没有表现出显著的地理谱系结构。单倍型邻接树结果也没有明显分支,未呈现出地域性差异。中性检验和核苷酸不配对分析结果揭示青蚶种群历史上经历了群体扩事件,扩张时间约为26万年前。研究结果为青蚶资源的保护和可持续利用提供了基础资料。 相似文献
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六个青蟹群体的线粒体16S rRNA和COI基因部分序列差异 总被引：6，自引：1，他引：5
对从广东阳江,广东吴川,广东珠海,福建东山,海南海口,海南三亚等六地区采集的六个青蟹群体进行分子遗传差异的研究。针对16S rRNA和COI序列进行群体间比对,聚类分析以及单倍型研究,其中各群体16S rRNA和COI序列相似度分别为99.69%,98.99%,平均遗传距离为0.033和0.018。聚类分析将全部个体的16S rRNA与Scylla paramamosain归为一类,将COI序列全部混杂,无按地理位置聚类现象。单倍型研究共发现33种单倍型,其中三亚群体单倍型分布最散,且在最为集中的A型中无三亚样本。研究结果表明东山等六地青蟹群体分子遗传背景基本相似。 相似文献
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基于线粒体COI 基因的毛蚶群体遗传多样性 总被引：1，自引：0，他引：1
采用PCR技术,扩增了大连、乳山、烟台、舟山4个毛蚶(Scapharca subcrenata)地理群体共38个个体的线粒体COI基因部分序列,并分析了4个毛蚶群体的遗传多样性和系统发育关系。研究结果显示:38个毛蚶COI部分序列经处理得到长度均为625bp的基因片段,共分为30种单倍型;基于COI部分序列的分析结果,毛蚶4个地理群体总的变异位点为301个,多样性指数Pi为0.15048,平均核苷酸差异数为92.242,单倍型多样性指数S为241。聚类分析显示毛蚶大连群体、乳山群体和烟台群体具有高度的遗传多样性,3个群体交叉聚在一起,没有明显的群体分化;舟山群体单独聚为一支,与其他3个群体分化明显。研究表明,线粒体COI基因不能单独做为毛蚶大连、乳山和烟台群体的遗传标记,但可以作为毛蚶舟山群体的有效群体遗传标记,为线粒体COI基因在群体遗传学的应用提供了基础资料。 相似文献