瓦氏雅罗鱼达里湖群体和乌苏里江群体的遗传多样性和遗传结构分析

选用5个瓦氏雅罗鱼(Leuciscus waleckii Dybowski)微卫星标记和13个草鱼微卫星标记,对分别采自内蒙古境内的达里湖和乌苏里江抚远江段的各15尾野生瓦氏雅罗鱼个体进行STR-PCR分析。结果显示,18个微卫星标记共检测到111个等位基因,平均每个基因座扩增得到6.1667个等位基因,观测杂合度(H o)0.1000～0.9333,平均为0.5315;期望杂合度(H e)0.0966～0.9328,平均为0.6298;多态信息含量(PIC)0.0905～0.9113,平均为0.5774;乌苏里江群体的平均等位基因数和平均观测杂合度分别为5.5556和0.5778,达里湖群体的平均等位基因数和平均观测杂合度均低于乌苏里江群体的平均等位基因数和平均观测杂合度,分别为4.3889和0.4852。2个群体间的遗传距离(D c)为0.2550。个体聚类结果显示,达里湖雅罗鱼所有个体聚为一簇,乌苏里江雅罗鱼所有个体聚为一簇。群体间的遗传分化指数(F st)为0.0855,数值介于0.05～0.15,N m值为2.6749,表明这2个群体处于中等分化,存在一定程度的基因交流。对2个群体的基因型进行了Hardy-Weinberg平衡的卡方检验,结果表明两群体均在一定程度上偏离了平衡。     

Population structure of the climbing perch,Anabas testudineus,in the lower Mekong River basin

Abstract Genetic variation in the climbing perch Anabas testudineus (Bloch) was investigated by sequencing 1047 base pairs of the mitochondrial ND2 gene. A total of 367 fish samples were collected from the Mekong River. The samples were separated into two genetically differentiated intra‐specific groups, the Laotian and Cambodian group, showing a population structure roughly in accordance with geographical location. Genetic differentiation between groups was confirmed by high pairwise F‐statistic values (0.52–0.98). Molecular clock analysis indicated that both populations were separated approximately 240 000 years ago. Additionally, samples within both groups could be divided into several regional small populations. Their genetic variation might have been supported not only by environmental factors including physical barriers, but also by historical events such as migration routes and/or timing of invasions into the Mekong River. These results could be valuable in identifying management units for the conservation of the species and its resource.     

绥芬河三块鱼和珠星三块鱼种群的生化遗传变异及亲缘关系

采用淀粉凝胶电泳方法，对由日本海溯河洄游到中国境内绥芬河的三块鱼（Tribolodonbrandti）和珠星三块鱼（Tribolodon hakonensis）繁殖群体的生化遗传结构及变异进行比较研究。结果表明，在选取的12种同工酶中共检测出27个基因位点，三块鱼和珠星三块鱼的多态位点比例分别为22．22％和18．52％，平均杂合度分别为0．0670和0．0695；除了三块鱼的Gpi-1和珠星三块鱼的Est多态位点外，两种鱼的Ldh—1、α—Gpd-1、Sdh—1、Aat—1及三块鱼的Est多态位点上的基因型分布都显著地偏离Hardy—Weinberg平衡，表现出杂合子明显缺失或过剩现象；三块鱼和珠星三块鱼种群间相同基因位点上的等位基因分布频率出现显著的分化，遗传相似度和遗传距离分别为0．6912和0．3693。结论认为，三块鱼和珠星三块鱼的遗传多样性已达到种的差异水平。     

中华绒螯蟹长江、黄河和辽河水系野生和养殖群体的遗传多样性

中华绒螯蟹(Eriocheirsinensis)是中国最重要的淡水养殖蟹类,广泛分布于东亚地区,养殖区域主要集中在长江、黄河和辽河流域。本研究基于线粒体DNAD-loop区评估辽河野生群体(LW)和养殖群体(LC)、黄河野生群体(HW)和养殖群体(HC)及长江野生群体(YW)和养殖群体(YC)的遗传多样性和种群结构。结果显示:(1)用于本研究的D-loop基因片段长度为477 bp,共包含234个变异位点和131个简约信息位点, 6个群体的262个个体中共有110个单倍型,包括90个独有单倍型和20个共享单倍型;(2)6个种群的单倍型多样性指数(Hd)范围为0.88889～0.96522,核苷酸多样性指数(π)范围为0.00887～0.01602,养殖和野生群体遗传多样性水平依次为:HCYCLC及HWLWYW;(3)6个群体的遗传距离(Da)范围为0.0119～0.0173,不论是养殖群体还是野生群体,辽河群体和长江群体之间的遗传距离均最小,且6个群体间遗传分化指数FST为0.12938。对6个群体进行中性检验显示Tajima’s D和Fu’s Fs的值均为负值。综上,基于线粒体D-loop基因的研究结果表明,三水系养殖和野生群体均具有较高的遗传多样性,且辽河和长江水系中华绒螯蟹的亲缘关系相对较近,该研究为中华绒螯蟹的种质资源评估、保护和开发提供了参考。     

Evidence for strong genetic structure in a regionally important, highly vagile cyprinid (Henicorhynchus lobatus) in the Mekong River Basin

Abstract –  For effective management of a freshwater species, it is necessary to have an understanding of the spatial scale of population differentiation. In many cases, common ecological methods such as mark-recapture are inappropriate for large freshwater systems. In this study, a molecular genetics approach was employed to determine the population structure of a small, but regionally very important, cyprinid species ( Henicorhynchus lobatus ) in the lower Mekong River Basin (MRB). A fragment of the mtDNA ATP ase 6 and 8 genes was sequenced for 136 individuals sampled from the main Mekong River channel, from two major tributaries of the Mekong River and from a site in an adjacent river drainage (Chao Phraya). An exact test and samova analysis revealed considerable differentiation among sites from the Mun River (a tributary of the Mekong River in Thailand) and all other samples from the MRB. Furthermore, the most upstream site in Lao PDR (BP) was significantly differentiated from sites further downstream. It is argued here that the former pattern is a result of historical drainage rearrangement and the latter a function of current ecological differences expressed as discrete migration pathways. The results of the study clearly show the existence of discrete population units for H. lobatus within the MRB that may require separate management strategies.     

浙闽沿海葡萄牙牡蛎群体遗传结构及种群历史分析

利用线粒体细胞色素氧化酶亚基因(mt COI)对浙闽沿岸5个葡萄牙牡蛎(Crassostrea angulata)自然群体的遗传结构及其种群历史进行分析。结果表明,葡萄牙牡蛎群体的遗传多样性处于较高水平,在183条序列中检测到44个多态性位点,共定义了39个单倍型;平均单倍型多样度和平均核苷酸多样度分别为0.8524和0.00406,平均核苷酸差异数在不同群体内差异较小。AMOVA分析显示,绝大多数的遗传变异都来自于群体内个体间(91.94%),组间和组内群体间均不存在明显的遗传分化。两两群体间的ΦST值较低(–0.01193~0.11486),但宁德群体与其他群体间出现了显著的低程度遗传差异。单倍型网络关系图整体上呈星状拓扑结构,不同地理来源的单倍型无明显分支。贝叶斯系统发生树上,各单倍型交错分布,没有表现出明显的地理分化。中性检验和错配分析均表明葡萄牙牡蛎群体经历了历史扩张,扩张时间在更新世末期的25万到21万年前。     

中国南海康氏马鲛线粒体COI序列遗传变异分析

在测定的采自广东饶平、阳江和广西东兴海域的62尾康氏马鲛( Scomberomorus commerson) 线粒体COI基因711 bp序列中,共检测到26个变异位点,18个单倍型,总体呈现出高单倍型多样性( Hd=0.8080.040)和低核苷酸多样性(=0.004 00.000 6)的特点。邻接树上出现了3个分支, 分支间Fst为0.811～0.833且P0.001,Nm为0.1～0.117;AMOVA分析显示分支间遗传变异占82.61%。表明3个分支间分化程度高,推测分歧时间为(89～22.67)万年前中更新世时期,可能原因是受到更新世冰期和间冰期交替的影响。但分支内与分支间都有不同地理来源的个体,没有出现明显的地理聚群;不同地理群体间Fst为-0.027～0.066,Nm均大于4或小于0;群体内个体间变异为96.34%。均表明群体间基因交流频繁,遗传分化程度并不高。3个分支中Clade A分支经历过种群快速扩张事件,可能是末次冰期期间康氏马鲛进入外海并受洋流及生存空间改变的影响。     

南海鸢乌贼的遗传差异:种群分化还是种间分化

利用线粒体ND2、COI和16SrDNA序列,对2012年9月至2015年9月采自南海的鸢乌贼(Sthenoteuthis oualaniensis)样本进行了种群遗传结构的分析。系统发育关系显示鸢乌贼中型群和微型群各自形成了单系群分支,而分支内没有形成与地理群体或季节群体对应的支系。分子方差分析同样表明,地理群体或季节群体之间不存在明显的遗传分化,而中型群和微型群之间具有极显著的遗传分化(F_ST=0.94092～0.9899, P<0.0001)。遗传多样性分析显示,鸢乌贼中型群和微型群均呈现出较高的单倍型多样性(0.9465和0.8545)和较低的核苷酸多样性(0.0051和0.0021),中型群的遗传多样性指数要高于微型群。基于ND2、COI和16SrDNA序列计算的中型群和微型群之间的遗传距离分别达到了14.0%、9.6%和8.8%,远大于类群内的遗传分化(平均<1%)。研究结果表明,南海鸢乌贼存在分布高度重合且有显著遗传分化的两个种群,即中型群和微型群。中型群和微型群之间的遗传差异达到了种间分化的水平,提示体型较大、具有背部发光器的中型群鸢乌贼(典型鸢乌贼)与体型较小、背部发光器缺失的微型群鸢乌贼可能是两个相互独立的种类。     

基于线粒体16SrRNA基因序列的长江下游重要水体脆弱象鼻溞群体遗传结构分析

为了解长江下游地区10个水体脆弱象鼻溞群体的遗传结构,研究测定了脆弱象鼻溞(Bosmina fatalis)线粒体16SrRNA基因序列,结果显示,100个样本中共有8个变异位点,定义了9个单倍型,单倍型多样性(Hd=0.284)和核苷酸多样性(Nd=0.000 76)均较低。AMOVA分子变异分析结果表明,脆弱象鼻溞遗传分化主要来自群体内,占93.33%,群体间的变异低,占6.67%。Fst值统计检验表明,各水体之间遗传分化不显著。系统发育树和中介网络图说明脆弱象鼻溞单倍型间关系较近,未形成明显谱系地理格局。中性检验和错配分布结果说明脆弱象鼻溞出现过群体扩张现象。     

Genetic connectivity and phylogeography of the night shark (Carcharhinus signatus) in the western Atlantic Ocean: Implications for conservation management

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珠江口水域秋季刺网的渔获组成及多样性分析

2014年9月使用3种不同结构（单片、双重、三重）和不同网目尺寸（40 mm、50 mm、60 mm）的刺网在珠江口水域进行了海上捕鱼试验,并从多样性和相异性两方面探讨了珠江口水域刺网渔业资源群落结构的差异。实验结果显示,3种刺网的渔获种类数、尾数和质量都随着网目尺寸的增大而减少;相对重要性指数（IRI）大于1 000的优势种有所差异,但深水金线鱼（Nemipterus bathybius）是共同优势种。针对珠江口渔获个体大小悬殊的特点,分别以个体数和生物量为基础计算了该水域的多样性指数,t检验结果显示这两者之间存在显著差异。采用欧氏距离法（Euclidian distance）计算,结果显示不同网目刺网渔业资源群落结构的差异性较高,而同一网目刺网差异性较低。从提高渔业资源群落结构的多样性和恢复其生态稳定性来看,控制网目尺寸是当前最主要和最有效的措施。     

基于微卫星标记的黄唇鱼遗传多样性研究

为了解安徽省内长江和淮河水系黄颡鱼 (Pelteobagrus fulvidraco) 遗传多样性和遗传结构,选用10个微卫星标记对9个自然群体共254尾黄颡鱼进行了遗传分析。共检测到等位基因数 (N_a) 245个,平均有效等位基因数 (N_e) 9.75个。各群体的平均N_a为5.20~14.80,平均N_e为2.64~8.93;平均观测杂合度 (H_o) 为0.496~0.671,平均期望杂合度 (H_e) 为0.557~0.818;平均多态信息含量 (PIC) 为0.500~0.790。AMOVA分析显示仅8.15%的遗传变异来自群体间,各群体间的遗传分化指数 (F_ST) 为0.006~0.236。基于Nei's遗传距离的UPGMA系统树和利用Structure软件的群体遗传结构分析均显示,9个群体可被划分4或5个谱系,其中石台 (秋浦河水系)、麻川河 (青弋江支流)、阜南 (淮河水系) 3个群体的个体遗传结构均比较独立,与其他群体亲缘关系较远;其他6个群体 (长江水系的望江、无为、龙窝湖、泾县群体和淮河水系的凤台、瓦埠湖) 的较为复杂,可能存在谱系间的混杂。结果表明,研究区域内黄颡鱼野生资源遗传多样性较高,地理群体间存在遗传分化且部分群体可能经历了瓶颈效应。

     

Population genetic divergence of bonnethead sharks Sphyrna tiburo in the western North Atlantic: Implications for conservation

1. Sharks are a priority for conservation because numerous species, including small-sized coastal species, are being heavily exploited by commercial and recreational fisheries. Understanding the genetic population structure of sharks is key to effective management, maximizing their evolutionary potential in a rapidly changing environment and preventing population declines.
2. Limited dispersal is an important factor promoting population divergence for several coastal shark species. The genetic variation in 14 microsatellite loci and 21,006 single nucleotide polymorphisms genotyped using restriction-site-associated DNA sequencing was analysed to assess the genetic structure of the bonnethead shark, Sphyrna tiburo, in the western North Atlantic.
3. Genetic differences were identified among three well-defined regions: the western Florida coast, the south-eastern US Atlantic coast, and the southern Gulf of Mexico. Results support previous studies based on mitochondrial DNA sequences in defining differences among these regions and suggest limitations of bonnethead sharks in routinely performing long-distance migrations.
4. The limited connectivity among regions explains the pattern of genetic divergence but also reported divergence at the species/subspecies level. These genetically discrete bonnethead populations have independent evolutionary histories that may include local adaptations to specific areas.
5. Bonnethead sharks are currently managed as two stocks in the USA owing to recent genetic, tagging, and life history studies; however, no stock assessments or management plans exist for Mexico. These results not only serve to reinforce US management strategies and provide critical data about the extent of gene flow and sex dispersal among populations, but also begin the process of effective management in the waters of Mexico to ensure the long-term productivity and resilience of this species. With an absence of gene flow between populations from US waters and the southern Gulf of Mexico, there is a need for management plans based upon independent biological and population dynamics data since limited or no opportunities for populations to interchange individuals may occur to re-establish population viability.

     

Genetic structure,origin, and connectivity between nesting and foraging areas of hawksbill turtles of the Yucatan Peninsula: A study for conservation and management

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Genetic population structure of <Emphasis Type="Italic">Nibea albiflora</Emphasis> in Yellow Sea and East China Sea

ABSTRACT:   The population genetic structure and level of gene flow of Nibea albiflora from the Yellow Sea and the East China Sea were examined with a 479-bp segment of a mtDNA control region. In total, 65 samples were collected from three locations and 37 haplotypes were obtained. Mean haplotype diversity and nucleotide diversity for the three populations ranged from 0.9130 ± 0.0308 (Zhoushan) to 0.9926 ± 0.0230 (Xiamen), and from 0.0073 ± 0.0043 (Qingdao) to 0.0099 ± 0.0057 (Xiamen). Analysis of molecular variance and pairwise F _ST revealed little genetic structure between the Yellow Sea and the East China Sea in N. albiflora . But based on the exact test of differentiation, the null hypothesis that N. albiflora within the Yellow Sea and the East China Sea constitutes a panmictic mtDNA gene pool was rejected. This might be caused by the broad spawning areas but not by the Yangtze River outflow. Mismatch distribution revealed that N. albiflora has undergone population expansion, possibly before the last 85 000–170 000 years. The existence of high gene flow between stocks in the studied area was supported by our results. Annual migrations, larval drift in the ocean currents, and recent range expansion could be the reasons for little genetic structure in the studied area.     

中国绥芬河三块鱼不同群体的种属划分及起源

为进一步明确中国绥芬河三块鱼属(Tribolodon)鱼类的分类地位及其起源,本研究依据表型和洄游产卵时间,将珠星三块鱼(Tribolodon hakonensis)、三块鱼(T.brandtii)及二者疑似杂交种与日本珠星三块鱼共53尾样本的COI基因序列进行了分析和比较。COI有效序列长度为637 bp,共检测到8种单倍型,其中三块鱼独享4种、珠星三块鱼独享3种、日本珠星三块鱼独享1种;疑似杂交种虽与三块鱼共享2种单倍型,却有80%的个体的单倍型与珠星三块鱼主效单倍型一致。系统进化分析显示,珠星三块鱼与珠星三块鱼南方型(sourthern forms of T.hakonensis)聚为一支,日本珠星三块鱼与珠星三块鱼北方型(northern forms of T.hakonensis)聚为一支,三块鱼(T.brandtii)单独聚为一支,由此可以确定日本海大彼得湾经俄罗斯滨海区溯河到中国河区产卵的三块鱼实为珠星三块鱼南方型和三块鱼。遗传距离结果显示,珠星三块鱼南方型和北方型的遗传距离为0.023,符合COI类群间的划分依据(0.02),支持将它们划分为两个有效种或亚种更妥当。依据COI分析结果,推测珠星三块鱼南方型和三块鱼存在杂交的可能性,提出了三块鱼野生种质资源保护和合理利用的相关建议。     

Population genetic structure of common bottlenose dolphins (Tursiops truncatus) in the Adriatic Sea and contiguous regions: implications for international conservation

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赤水河浮游植物群落结构特征及其与水环境因子的关系

于2007-2010年在长江上游珍稀、特有鱼类国家级自然保护区赤水河段进行浮游植物和水质监测调查研究, 浮游植物调查结果显示, 共鉴定出浮游植物8门517种(属), 贡献率最大为硅藻门(Bacillariophyta), 占藻类总数比例平均为67.97%。繁殖期浮游植物密度和生物量平均值范围分别为11.95×10⁴~ 28.31×10⁴ cell·L^-1和0.36~0.94 mg·L^-1; 育肥期密度和生物量平均值范围分别为10.32×10⁴~33.73×10⁴ cell·L^-1和0.25~0.60 mg·L^-1; 越冬期密度和生物量平均值范围分别为11.53×10⁴~26.38×10⁴ cell·L^-1和0.39~0.76 mg·L^-1。群落Shannon-Wiener多样性指数(H'') 、Margalef丰富度指数(d)、Pielou均匀度指数(J)平均值分别为4.42、6.93、0.84, 土城采样断面水体为轻度污染, 其他采样断面水体均无污染。物种—环境典型对应分析(CCA)分析显示, 繁殖期群落结构主要影响因子为硝酸盐氮( -N)、亚硝酸盐氮(-N)、总氮(TN)等含氮营养盐类, 育肥期为镁离子(Mg²⁺), 越冬期为水温(WT)、pH、溶氧(DO)、钙离子(Ca²⁺)。本研究通过分析这一国家级自然保护区赤水河段的浮游植物群落结构特征, 并探讨赤水河段浮游植物群落结构及其环境因子的关系, 旨在为保护区赤水河段的水生态环境管理与水生生物资源保护措施的制定提供基础参考依据。     

西藏雅鲁藏布江双须叶须鱼的年龄结构与生长特征

根据2008–2009年、2012年以及2013年采自雅鲁藏布江水系的956尾样本对双须叶须鱼(Ptychobarbus dipogon)的年龄结构和生长特征进行研究。雌性渔获物体长范围为146~569 mm,雄性渔获物体长范围为167~506 mm,性别未辨渔获物体长范围为78~297 mm;耳石上的年轮形成于每年的3–6月份;估算的雌性群体年龄范围为3~24龄,雄性群体年龄范围为3~13龄,性别未辨群体年龄范围为2~6龄。体长(Ls)–体重(W)方程分别为:W=2.494×10–5Ls2.877(雌性),W=2.790×10–5Ls2.856(雄性);拟合出来的von Bertalanffy生长方程为:Lt=606.9[1–e–0.114(t+0.163)],Wt=2538.4[1–e–0.114(t+0.163)]2.88(雌鱼);Lt=496.3[1–e–0.162(t–0.018)],Wt=1391.1[1–e–0.162(t–0.018)]2.86(雄鱼)。估算的雌鱼和雄鱼的拐点年龄分别为9.1龄和6.5龄,对应的体长和体重分别为396.0 mm、743.6 g和322.5 mm、406.3 g。研究表明,双须叶须鱼种群结构趋向低龄化,可能受全球气候变化、生物入侵和过度捕捞等因素的影响。针对这些影响因素,本研究提出了相应的渔业管理措施。