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1.
近来的研究表明,一些所谓的环球或环极地分布的广布种实际上包含着一些局限性分布的隐存种,物种多样性可能被低估。本文采用形态学和DNA条形码技术相结合的方式,对印度洋和西北太平洋海域的龟螺属(Cavolinia)和小龟螺属(Diacavolinia)的种类进行了分类学研究和物种鉴定。结果表明,线粒体16S rRNA基因数据不支持小龟螺属形态种的划分,分布于西北太平洋的D. grayi、D. vanutrechti、D. pacifica、D. elegans、D. angulosa等多个形态种可能属同一个种,即长吻小龟螺(D. longirostris)。COI基因数据也不支持钩龟螺(C. uncinata)亚种和变形的划分。许多形态特征不能作为种或种下分类单元的区分依据。钩龟螺、球龟螺(C. globulosa)和长吻小龟螺在COI系统树中均形成2个地理支系,其内部可能存在隐存种。西北太平洋海域长吻小龟螺的核基因组中存在线粒体假基因,对DNA条形码分析产生严重干扰。  相似文献   

2.
南海长棘海星暴发已严重威胁到该海域珊瑚礁生态系统健康,乃至整个南海生物多样性。针对南海长棘海星拉丁学名混用、中文名不统一的现状,我们采集了中沙群岛济猛暗沙海域长棘海星样品,结合长棘海星此前物种分类和分布的研究结果,对南海长棘海星物种有效性进行探讨。结果表明:所有长棘海星序列明显分为4个类群,各类群间遗传距离范围为0.087 5~0.104 7,达到了种间差异水平。南海长棘海星与长棘海星的太平洋种聚类到一起,实为太阳长棘海星(Acanthaster solaris),与其余3个种存在明显的种间差异。太阳长棘海星中2个支系间的遗传距离为0.005 3,在COⅠ基因层面属于种内差异。南海长棘海星物种有效性的研究结果为后续开展其遗传特征与适应性机制、种群分布与扩散机制、种群暴发机制等内容的研究提供科学依据。  相似文献   

3.
长棘海星(Acanthaster planci)的暴发是导致我国南海乃至印度—太平洋海域珊瑚礁退化的主要原因之一。浮游幼体的密度是决定成体种群是否暴发的重要指标, 但是由于幼体肉眼不可见且不易分辨, 常规调查和显微镜观察均无法有效检测到自然海域的长棘海星幼体, 因此迫切需要开发一种高灵敏性且特异性的长棘海星幼体检测技术。本研究针对长棘海星幼体线粒体细胞色素氧化酶亚基I(mtCOI, mitochondrial cytochrome oxidase subunit I)基因序列, 建立了基于聚合酶链式反应(PCR, polymerase chain reaction)的长棘海星幼体特异性检测技术, 并对西沙七连屿珊瑚礁海域的长棘海星幼体进行了检测。结果表明, 设计筛选的4对特异性引物均可以扩增长棘海星ApmtCOI基因片段, 且与蓝指海星(Linckia laevigata)、面包海星(Culcita novaeguineae)、粒皮海星(Choriaster granulatus)和吕宋棘海星(Echinaster luzonicus)没有交叉反应。在退火温度为58.5℃时, 引物2aooniF/2aooniR的特异性最佳, 具有较高的灵敏度, 可检测到皮克级的长棘海星基因组DNA。利用该技术检测了西沙七连屿海域长棘海星幼体分布情况, 发现10月底西沙七连屿珊瑚礁海域能检测到长棘海星幼体, 且幼体分布并不均匀。因此, 该检测技术可作为今后长棘海星幼体种群监测的有效方法。  相似文献   

4.
多棘海盘车(Asterias amurensis)是海星纲的一个致灾物种,广泛分布于包括我国黄海、渤海海域、韩国、日本和俄罗斯海域在内的北太平洋海域,并作为入侵种分布于澳大利亚的塔斯马尼亚海域。多棘海盘车在多个海域发生过暴发性增殖导致的高密度、大规模聚集,对海洋生态系统和水产养殖造成严重的负面影响。自2006年以来在我国山东青岛海域多次发生大规模多棘海盘车聚集,对贝类养殖造成重大经济损失。日本、俄罗斯、澳大利亚等海域的多棘海盘车遗传多样性研究取得了显著进展,然而,迄今为止鲜有针对我国海域致灾物种多棘海盘车的分子生物学分析,阻碍了我国海域种群与全球种群间遗传进化关系的比较分析。研究重点分析了于2022年7月在胶州湾发生多棘海盘车暴发时采集的12个样本,系统组装了其线粒体基因组、核糖体基因簇以及多种通用分子标记。基于线粒体基因组和核糖体基因簇的系统发育分析表明多棘海盘车具有较高的种内遗传多样性。基于线粒体基因组的蛋白编码基因进行分化时间估算,多棘海盘车的种内遗传分化可能发生在1.7~4.2 Ma,表明多棘海盘车的扩布可能较早发生。与线粒体基因组相比,多棘海盘车核糖体基因簇序列在种内极为保守...  相似文献   

5.
采用线粒体DNA 16S rRNA和COⅠ基因序列对福建、浙江沿海分布的5个小孔蛸(Cistopus sp.)群体进行了遗传多样性研究。结果表明,序列总长度分别为497-501bp(16S rRNA)和652bp(COⅠ);小孔蛸5个群体的序列碱基组成均显示出较高的A+T含量(16S rRNA基因72.1%,COⅠ基因65.9%)。16S rRNA基因片段在种内和群体间个体差异均较小,5个群体共检测到8个变异位点(其中7个插入/缺失位点);COⅠ基因序列不存在插入/缺失位点,群体内个体间变异位点数为21个。系统进化树表明,宁德群体和象山群体与其它三个群体的亲缘关系较远,但存在基因交流。线粒体16S rRNA和COⅠ基因在群体间无显著多态性分布。  相似文献   

6.
北部湾海域球形棕囊藻遗传多样性分析   总被引:6,自引:3,他引:3  
南海北部湾海域近年来连年暴发球形棕囊藻赤潮,严重威胁近海生态安全,亟待探明赤潮成因。球形棕囊藻是一种广泛分布于温带至热带海域的有害藻华微藻,具有明显的种下遗传分化。为了解北部湾海域球形棕囊藻的遗传多样性及其对赤潮藻种来源的指示意义,本研究针对分离于北部湾海域赤潮发生期间的4株棕囊藻,以核糖体28S大亚基rRNA基因(28S rDNA)D1-D2区和转录间隔区(ITS区)为靶区构建克隆文库,通过测序分析了北部湾海域球形棕囊藻的遗传多样性。结果表明,从北部湾分离的4株棕囊藻均为球形棕囊藻,但不同年份分离的球形棕囊藻藻株之间存在明显的遗传差异。部分球形棕囊藻藻株(PG2015和PG2017)的不同克隆间也存在遗传差异,这种遗传差异在由单一藻细胞建立的克隆培养系中仍存在,表明遗传差异是来自细胞内多拷贝的基因序列,可能源自不同地理种群球形棕囊藻之间的基因交流。与ITS区相比,28S rDNA D1-D2区能更好地反映球形棕囊藻遗传多样性状况,具有作为分子标记指示球形棕囊藻地理种群的潜力,但仍需深入研究。研究结果深化了对北部湾球形棕囊藻遗传多样性的认识,有望为进一步解析北部湾海域球形棕囊藻赤潮原因种来源提供判据。  相似文献   

7.
印度洋-西太平洋海洋动物谱系地理演化格局   总被引:2,自引:1,他引:1  
印度洋和西太平洋海域,拥有大量浅海大陆架、边缘海和岛屿,孕育了全球最丰富的初级生产力和渔业资源,尤其是作为该区域陆源物质输入、两大洋能量汇聚中心和生物多样性中心的东印度三角,在全球海洋生物分布和进化中扮演了重要角色。本文结合物理海洋和化学海洋环境,通过线粒体基因和核基因等分子标记研究结果,归纳分析了印度洋和西太平洋区域海洋动物谱系生物地理演化格局及其可能的成因。具体结果如下:(1)雷州半岛-海南岛、冰期暴露的台湾海峡和长江冲淡水等沿岸海区,阻碍了海洋动物在海区间的扩散,南海、东海和黄、渤海广布类群,多由一个星状辐射谱系组成,种群经历最近的数量扩张和区域扩散,而仅分布于南海的物种,一般具有多个深度分歧的遗传谱系,种群呈现出数量平衡状态,同一广布物种的南海和东海种群,因区域海洋环境差异,种群数量动态演化历史不同;(2)黑潮影响区的沿岸广布类群,黑潮海流促进了顺流扩散、限制了跨海流基因交流;(3)东印度三角区,存在"华莱士线"、"赫胥黎线"和"印度洋-太平洋线"等生物地理边界,该区域海洋或咸淡水溯河洄游动物多呈现为分布在生物地理边界两侧的2个遗传谱系;(4)西太平洋,存在与目前东西向大洋环流垂直的南北向跨赤道扩散和基因流现象,可能受到目前南北向随季节反转的沿岸流和深层海流影响;(5)印度洋东西海岸共享物种,受印度洋西向赤道流影响,海洋动物多由东印度洋向西印度洋跨洋扩散;(6)西印度洋广布物种/类群,呈现了两种不同种群分化格局——遗传同质均一种群和深度分化的遗传谱系;(7)东、北印度洋和南海区域共享大量物种,可能是海盆间双向扩散的结果;(8)海洋生物谱系生物地理进化史信息,可以用于地质事件、海洋环流和古气候重建。  相似文献   

8.
茎柔鱼广泛分布在东太平洋海域,分布海域广、群体结构复杂,赤道附近海域(120°W~110°W)群体与秘鲁外海(5°S~20°S)群体是否存在关联,目前尚不清楚。本文通过基因组高通量测序技术获得了12个多态性SSR位点,利用这12个位点,对茎柔鱼赤道海域群体与秘鲁外海群体进行遗传变异分析。结果表明,所有的SSR位点均为高度多态性位点(PIC为0.795~0.945),位点DG07与DG09极显著偏离Hardy-Weinberg平衡(P0.01)。赤道海域群体(Ho=0.725,Hc=0.897)与秘鲁外海群体(Ho=0.697;He=0.874)均显示出较高的遗传多样性水平,群体间存在显著的遗传分化(Fst=0.020 46,P0.01)。太平洋赤道海域近表层存在的复杂海流系统有可能阻碍群体间发生基因交流。建议将茎柔鱼赤道海域群体与秘鲁外海群体看作2个管理单元。  相似文献   

9.
基于线粒体COI基因序列的中国鲷科鱼类系统进化关系   总被引:1,自引:0,他引:1  
采用PCR特异性扩增了采集于中国沿海的鲷科5属11种鱼类的线粒体COI基因序列,并结合Gen Bank已有的同源序列,对中国鲷科6属12种鱼类的分子系统进化关系进行研究。结果表明,中国鲷科6属12种鱼类的COI基因序列的平均碱基组成为T 30.4%、C 27.7%、A 23.5%、G 18.4%;属间Kimura双参数平均遗传距离为9.5%—19.7%,种间平均遗传距离为2.2%—21.8%,其中四长棘鲷属、赤鲷属和犁齿鲷属间的遗传距离(8.2%—13.8%)接近于棘鲷属多数种间遗传距离(6.5%—12.2%);分子系统树显示中国鲷科鱼类分为两大类群,类群I包括四长棘鲷属、犁齿鲷属、赤鲷属、牙鲷属等红体色种类,类群Ⅱ含平鲷属、棘鲷属等银灰体色种类,其中棘鲷属的冲绳棘鲷和黄鳍棘鲷先聚为姐妹群,澳洲棘鲷、黑棘鲷、灰鳍棘鲷和台湾棘鲷聚为另一支。本文结合已有研究结果得出:中国鲷科鱼类属间是先按体色、后按牙齿分化的,四长棘鲷属、犁齿鲷属和赤鲷属有相当密切的亲缘关系;中国棘鲷属是一个有共同祖先的单系群,属内存在两个平行进化的分支,两分支的种间关系具有明显的分化。  相似文献   

10.
中国北方习见水母类的DNA 条形码分析   总被引:5,自引:0,他引:5  
本研究获得了中国北方近海习见水母类24个种共62条线粒体细胞色素C氧化酶亚基I(mtCOI)序列,结合GenBank中具DNA条形码关键词的mtCOI序列,共比较了水母类mtCOI片段207条,水母mtCOI种内遗传差异在0%-7.4%之间,均值为0.9%(SD=0.014),其中约93%的个体种内差异小于4%;近源种间遗传差异在5.4%(Sarsia)到44.9%(Lensia)之间,均值为25.1%(SD=0.118),97%以上的个体种间遗传差异大于10%。绝大多数(98.8%)水母种类种内遗传差异小于种间遗传差异,条形码间隙明显。本研究涉及的中国北方习见水母种内遗传差异均显著小于种间遗传差异,结果表明以mtCOI作为DNA条形码可以实现对中国北方习见水母种类鉴定。利用DNA条形码序列分析,梳理了中国近海一些常见水母的分类地位。此外,对4种保存液保存方法的比较研究表明,90%乙醇、DMSO、RNA Safer和DNA Conserver4种保存液无法同时保存形态学特征和DNA序列,但DNA Conserver的效果相对较好。  相似文献   

11.
Barriers to dispersal are recognized to play an important role in the differentiation of populations and ultimately in speciation. In the southeast Pacific, on the northern coast of Peru, a transition zone between the Peruvian and Panamic marine biogeographic provinces exists. Here, the convergence between two contrasting surface currents could generate a barrier effect for the larval dispersal of meroplanktonic invertebrates, which could in turn generate differentiated populations or genetic lineages on both sides of the transition zone. To address this, we studied to Echinolittorina paytensis, an abundant rocky intertidal periwinkle that spans both biogeographic provinces. A total of 95 individuals from Ecuador (2°19′S) to central Peru (7°31′S), covering the Panamic Province, the Peruvian Province, and the transition zone between, were collected. The mitochondrial markers cytochrome c oxidase I and 16SrRNA were sequenced in order to investigate phylogeography and genetic structuring. In general, no genetic structuring was found across the transition zone, suggesting this biogeographic boundary would not be acting as a barrier in this species. Factors such as a high larval dispersal capability and the occurrence of El Niño–Southern Oscillation events such as El Niño are discussed.  相似文献   

12.
The study investigated the global and regional phylogeography of the yellowtail kingfish Seriola lalandi by examining genetic diversity and population genetic structure of this species at inter-and intra-ocean level and on a regional scale. DNA fragments of two mitochondrial genes, cytochrome b (Cytb) and cytochrome c oxidase subunit I (COI) and one nuclear gene, recombination activating gene 1 (RAG1), were sequenced to investigate the global-scale phylogeography of this species. The population genetic structure within the South Pacific, as well as along the South African coastline, was examined further using six microsatellite markers. Three distinct clades were identified for S. lalandi, which correspond with previously described subspecies of the North-East Pacific, North-West Pacific and the Southern Hemisphere. Within the latter, additional divergence was observed between the South Pacific and the South-East Atlantic regions. Divergence estimates were indicative of a Pacific origin for S. lalandi populations, because of Pleistocene vicariant events. Microsatellite analyses revealed overall significant genetic differentiation between South African and South Pacific samples. This corroborates recent findings on the global phylogeography of the species. No population differentiation was observed within South Africa, indicating high levels of gene flow.  相似文献   

13.
Small crustaceans are diverse and abundant in seagrass habitats and provide many ecological services. Further information is needed about their long‐ and short‐term response to habitat fragmentation and loss. Shrimp specimens were sampled from coastal seagrasses: latitudes 9°–27° S (Torres Strait to Moreton Bay, Queensland, Australia) and longitudes 141°–153° E (Weipa to Moreton Bay, Queensland, Australia). The seagrass shrimp Phycomenes zostericola (Caridea: Decapoda) underwent phylogeographic analysis using mitochondrial and nuclear sequence data. Lineage relationships were investigated and two deeply divergent sympatric lineages of P. zostericola were discovered in northern samples. The two lineages display vastly different demographic histories in spite of similar overall phylogeographic patterns. The two lineages appear to be in secondary contact with each other, detailing independent histories of sea level change, long distance colonisation and habitat fragmentation. Their regional structure is evidence that the potential for dispersal is only realised under specific environmental conditions. Nuclear data, used to determine reproductive status between lineages, instead displayed a non‐random latitudinal geographic distribution suggesting directional selection, possibly in response to ocean temperatures. The differences between the two deeply divergent lineages highlight the importance of understanding variability among cryptic taxa and their response to habitat change.  相似文献   

14.
外来囊藻(Colpomeniaperegrina)是一种在潮间带分布广泛的褐藻,它能附着在牡蛎壳上进行跨海区扩散,因而是研究生物多样性变动和生物地理格局形成的良好模型。外来囊藻在中国沿海虽有分布,但关于其种群遗传多样性和分化研究的报道尚为空白。本研究采集了中国近海13个外来囊藻种群样本。通过扩增301条线粒体cox3序列,发现了26个单倍型;通过重建单倍型网络图和基于最大似然法与贝叶斯法重建系统进化树,发现外来囊藻种内遗传多样性较高, 13个种群划分为3个遗传世系,其中浙江南麂列岛的7个种群组成遗传世系A,辽宁和山东的样本则分化为遗传世系B和C。中国近海外来囊藻的这种种群遗传结构可能源于更新世末次盛冰期黄渤海、东海边缘海的环境变化和海平面的大幅下降。遗传世系A具有的较高单倍型多样性,其原因可能是南麂列岛独特的地理位置和潮间带环境的共同作用。  相似文献   

15.
Size distributions of Neocalanus cristatus, N. flemingeri and N. plumchrus were investigated in the eastern and the western subarctic gyres and three marginal seas of the North Pacific during the diapause period to examine the geographical variation in body size of Neocalanus species and to clarify the origin of the large biennial N. flemingeri which has been observed in the Oyashio region. There were significant among region variations in body sizes for all three species of Neocalanus. Generally, the body sizes of the copepods were larger in the marginal seas and marginal areas of the open ocean. In the open ocean, the body sizes increased westward. These patterns of variation in the body sizes roughly correlated with local food availability. Distribution of biennial N. flemingeri was restricted to the Sea of Japan, the Okhotsk Sea and the Oyashio region. The large-sized biennial N. flemingeri were abundantly observed in the Okhotsk Sea, and the medium-sized biennial individuals were observed in the Sea of Japan. These facts strongly suggest that the large biennial N. flemingeri in the Oyashio region are advected from the Okhotsk Sea.  相似文献   

16.
17.
Penaeus semisulcatus, the green tiger prawn, is an ecologically and economically important penaeid shrimp in the Indo‐West Pacific region, especially in rice‐shrimp farming and capture fisheries in Bangladesh and Sri Lanka, respectively. Genetic variation and phylogeography of samples of this species from Bangladesh and Sri Lanka were studied utilizing different mitochondrial DNA markers, i.e. cytochrome oxidase subunit 1 (CO1), control region (CR) and 16S rRNA genes. No evidence of population structure was observed in Bangladesh, but distinct variations were found among the Sri Lankan samples (ΦST = 0.04, p = .002; FST = 0.07, p = .001), with the western sample differing from the northwestern and southern samples. The Bangladesh population had lower genetic diversity than two of the three Sri Lanka populations. The phylogeography of P. semisulcatus revealed two distinct mitochondrial DNA (mtDNA) lineages, one in the Western Pacific Ocean and second in the Indian Ocean. The Bangladesh samples showed highest levels of similarity with samples from Sri Lanka, India and Malaysia, with the Bangladesh and Sri Lanka populations sharing the most common recent ancestry. Among the Indian Ocean samples, high levels of variation were observed in the samples from Iran, indicating admixture of two distinct mtDNA lineages, one shared by the populations from the Bay of Bengal and the other possibly originating from Eastern Africa. The genetic and phylogeographic information obtained in this study will be useful in appropriate planning for management and conservation of shrimp fisheries in Bangladesh and Sri Lanka, and in the Indo‐West Pacific region.  相似文献   

18.
Populations of the copepod species Calanus finmarchicus often dominate the springtime biomass and secondary production of shelf ecosystems throughout the North Atlantic Ocean. Recently, it has been hypothesised that interannual to interdecadal fluctuations observed in such populations are driven primarily by climate-associated changes in ocean circulation. Here, we compare evidence from the North Sea and Gulf of Maine/Western Scotian Shelf (GoM/WSS) linking fluctuations in C. finmarchicus abundance to changes in ocean circulation associated with the North Atlantic Oscillation (NAO). A particularly striking contrast emerges from this Trans-Atlantic comparison: whereas the North Sea C. finmarchicus population exhibits a negative correlation with the NAO index, the GoM/WSS population exhibits a more complex, positive association with the index. The physical processes underlying these contrasting population responses are discussed in the context of regional- to basin-scale circulation changes associated with the NAO.  相似文献   

19.
We report on the extraordinary findings of several endemic species of North Pacific deepwater fish and squid on the continental slope of the Falkland Islands in the Southwest Atlantic, namely the giant rattail grenadier Albatrossia pectoralis (Macrouridae), pelagic eelpout Lycodapus endemoscotus (Zoarcidae) and squid Gonatopsis octopedatus (Gonatidae). These deepwater dwellers might have moved more than 15,000 km from their common species ranges with Pacific Deep Water along the western slopes of both Americas and through the Drake Passage. Our findings provide further evidence of the possible role of deepwater currents in the dispersal of bathypelagic and benthopelagic animals from one polar region to another across various climatic zones of the world ocean.  相似文献   

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