6个不同海域文蛤地理群体的亲缘关系分析

为探究中国辽东半岛海域(辽宁群体)、长江口及其两翼海域(江苏群体)、台湾海峡西部海域(福建群体)、珠江口及其两翼海域(广东群体)、北部湾海域(广西群体)以及日本伊势湾海域(三重群体)6个不同海域文蛤(Meretrix meretrix)地理群体的亲缘关系,采用18S rRNA基因、线粒体细胞色素氧化酶c亚基Ⅰ(COⅠ)及16S rRNA基因3种分子标记进行序列测定与分析。测序结果显示,3种基因序列长度分别在1 854、658、596 bp左右;18S rRNA基因碱基组成无偏异,序列较为保守;COⅠ与16S rRNA基因A+T平均含量明显大于G+C含量,符合线粒体基因组成特征。通过Meg Align软件比对6个地理群体文蛤,序列相似百分比分别为99.7%~100.0%(18S)、91.7%~99.8%(COⅠ)、90.2%~99.8%(16S),其中三重文蛤序列差异最大;以文蛤属的帘文蛤(Meretrix lyrata)作外群,采用MEGA 5.03软件中相邻连接法(NJ)构建系统发育树显示,我国沿海5个文蛤群体聚为一枝且与日本三重文蛤分开,自展值分别为67%(18S)、99%(COⅠ)、98%(16S);我国沿海5个文蛤群体中,辽宁、江苏、福建文蛤群体首先聚在一起,其次是广西文蛤群体,最后是广东文蛤群体。研究结果表明,辽宁、江苏、福建文蛤群体同源性较高,亲缘关系最近;广西文蛤群体、广东文蛤群体与我国其它文蛤群体间遗传差异较大,地理遗传分化明显;而日本三重文蛤与我国沿海文蛤可定为文蛤的2个地理亚种。     

日本沼虾淀山湖群体和两个杂交选育群体生长性能比较

为了评价日本沼虾淀山湖群体选育子代和杂交选育子代的生长性能,对淀山湖自繁群体和两个杂交选育群体进行了室内养殖对比试验。结果显示:与淀山湖青虾自繁子代(DS)F7相比,淀山湖♀×洞庭湖♂(SD)F1代的体质量日增长量较大,生长速度较快,淀山湖♀×长江♂(SC)F1代的体长日增长量较大,SD和SC群体表现出显著的杂交优势(P<0.05),两个杂交群体之间没有显著性差异。试验结果可为淀山湖日本沼虾的种质创新和良种选育提供一定的理论参考依据。     

翘嘴鲌四个育种群体的遗传差异分析

利用微卫星(SSR)标记对翘嘴鲌(Culter alburnus)4个育种群体(黑龙江水系群体、淮河水系群体、长江上游水系群体和长江下游水系群体)的遗传差异进行了分析。结果显示:4个育种群体均存在杂合子缺失现象,群体内近亲繁育程度较高,群体遗传多样性水平较低;群体间遗传差异的分子方差分析(AMOVA)显示,遗传变异主要来源于群体内个体间,群体间的变异为17.58%(FST=0.1758,P0.001);NJ聚类树显示,黑龙江水系群体与淮河水系群体的遗传关系最远,长江上游水系群体与长江下游水系群体的遗传关系最近;而STRUCTURE遗传聚类分析显示,4个育种群体各自单独聚为一类为其最佳遗传分组。综合分析结果表明,4个育种群体的遗传变异较小,遗传多样性水平均较低,在育种时,应进一步扩大亲本来源,增加亲本数量,充实育种群体的遗传多样性。     

凡纳滨对虾全基因组SSR标记开发及不同养殖群体的遗传多样性

为了探究SSR标记对凡纳滨对虾养殖群体的遗传多样性和群体遗传结构的影响,为凡纳滨对虾种质资源的遗传改良提供基础信息。实验利用MISA软件对凡纳滨对虾全基因组SSR位点进行搜索,通过聚丙烯酰胺凝胶电泳获得多态性高的SSR标记,基于POPGENE 1.32、PIC-CALC和Mega 6.0软件分析6个不同来源的凡纳滨对虾养殖群体的遗传多样性和群体结构特征。在凡纳滨对虾全基因组数据中共鉴定出10 453 975个微卫星,约占基因组序列总长度的18.56%,其中,二碱基微卫星最丰富,占总数的82.15%。利用具有多态性的14个SSR标记分析3个国内群体[桂海1号(CG)、海兴农2号(CH)和山东养殖群体(CT)],及3个国外群体[厄瓜多尔1号(FO)、厄瓜多尔2号(FT)和墨西哥群体(FM)]的遗传特征。结果显示,14个SSR标记在6个群体中共检测到208个等位基因变异,等位基因数、观测杂合度、期望杂合度和多态性信息含量的范围分别为6～25、0.112～0.994、0.234～0.925和0.226～0.918;遗传多样性丰富程度为CH>FO>FM>CT>FT>...     

文蛤转录组中微卫星位点生物信息分析#br#

采用生物信息学方法分析了文蛤(Meretrix meretrix)转录组中微卫星序列(简单重复序列,simple sequence repeat)的分布规律。结果表明:在文蛤转录组SSR中,单碱基重复序列的数量最多,有3001个;其次为三碱基和四碱基重复序列,分别为2254和2200个;二碱基重复序列1052个;五碱基重复序列332个;六碱基重复序列最少,仅13个。文蛤转录组SSR共包含26种重复基元,其中优势基元为单碱基重复A/T有2809个,其次为三碱基重复AAC/TTG有907个,四碱基和二碱基重复中的AAAC/TTTG和AT/TA分别有588和561个,说明文蛤转录组微卫星位点的分布对A/T具有偏好性。文蛤完整SSR的平均长度为18.34 bp,长度分布在12~20 bp,约占41%。研究结果将为研究文蛤SSR标记开发、群体遗传多样性、遗传连锁图谱、种质资源鉴定和分子遗传育种等后续研究提供基础数据。     

4 个斧文蛤群体微卫星标记的遗传多样性分析

为研究斧文蛤(Meretrix lamarckii)不同地理群体(浙江苍南群体、福建长乐群体、福建宁德群体以及广东汕头群体)的遗传结构和系统发生关系,采用13对微卫星分子标记,对4个不同地理群体进行了分析。结果显示,13对引物共检测出63个等位基因,每个位点等位基因数(Na)2~7个,平均每个位点观测等位基因数(Na)为4.87;有效等位基因数(Ne)为1.927~2.591;平均观测杂合度(Ho)为0.437~0.562;平均期望杂合度(He)为0.446~0.549;平均多态信息含量(PIC)为0.383~0.490;Hardy-Weinberg平衡检验表明,4个群体的大部分微卫星位点都偏离平衡状态(P0.05);UPMGA聚类分析表明,浙江苍南群体与福建宁德群体聚为一支,福建长乐群体和广东汕头群体聚为一支;群体间遗传变异指数Fst为0.230 9,表明4个斧文蛤群体间的遗传变异为23.09%。研究表明,斧文蛤4个不同地理群体遗传多样性处于中等多态水平;4个群体的遗传距离与它们实际的地理分布情况基本一致;4个地理群体间的变异较大,遗传分化水平较高。该研究为斧文蛤种质资源的有效保存、管理和恢复提供了理论依据。     

浙江和广西两种文蛤的分子鉴定及形态特征分析

以文蛤如东群体(RD)和北海群体(BH)为对照群,利用线粒体COⅠ基因序列分析技术对苍南文蛤(CN)和北海白壳文蛤(BW)进行了分子鉴定。结果表明,苍南文蛤和斧文蛤的碱基组成非常相似,通过文蛤属贝类基因序列同源性比对和分子系统聚类分析发现,苍南文蛤CN1、CN2与斧文蛤的同源性分别达到100.0%、99.2%,在依据遗传距离构建的系统进化树上,2个苍南文蛤也与斧文蛤单独聚为一支,据此将苍南文蛤确定为斧文蛤,此结果将斧文蛤的分布区域向北扩展到了浙江南部沿海,修正了现有文献中记载的仅在我国南海诸省分布的说法;而白壳文蛤与其它6种文蛤的基因序列同源性都不高(79.6%~85.3%),在系统进化树上单独分出一支,明显是独立于这些文蛤之外的新种。斧文蛤、白壳文蛤与文蛤群体COⅠ基因的遗传多样性分析显示,文蛤BH群体的变异位点数、单倍型数和核苷酸多样性指数均最大,斧文蛤其次,而白壳文蛤10条基因序列完全相同,未发生任何核苷酸位点变异,说明其遗传多样性很低。应用方差分析和Tukey多重比较,分析了斧文蛤、白壳文蛤与文蛤群体的形态差异,发现斧文蛤的壳长明显大于壳高,且SMW/TW、IW/TW 2个参数与文蛤、白壳文蛤群体差异显著(P<0.05);而白壳文蛤的壳宽指数大、壳型相对膨胀,SW/SL和SW/SH值均最大,与文蛤和斧文蛤群体差异显著(P<0.05)。本研究结果可为文蛤属贝类种间鉴别、种质资源保护及系统进化研究提供基础资料。     

墨西哥湾扇贝和扇贝“渤海红”及其杂交子代的遗传分析

利用SSR (Simple Sequence Repeats)分子标记技术，对扇贝“渤海红”、墨西哥湾扇贝(Argopecten irradians concentricus)及其杂交子代3个群体共90个个体的遗传多样性进行分析。结果显示，8个SSR位点共扩增出67个等位基因，各位点等位基因数范围为4~14个，平均等位基因数为8.5个。扇贝“渤海红”有效等位基因数(Ne)、平均观测杂合度(Ho)和多态信息含量(PIC)最高，分别为2.3947、0.504和0.462；3个群体的遗传分化指数(Fst)、基因流(Nm)和固定系数(Fis)分别为0.1398、1.5387和0.3698。对亲代与杂交子代间的遗传分化分析表明，杂交子代与扇贝“渤海红”的遗传距离最小(0.1188)，遗传相似度最大(0.888)，杂交子代的遗传结构更偏向亲本扇贝“渤海红”。研究结果可为扇贝“渤海红”和墨西哥湾扇贝群体种质资源评估和杂交新品种的选育提供理论参考。     

文蛤属2种贝类多变量形态分析及日本文蛤的物种有效性

为探讨日本文蛤与中国文蛤属2种贝类的形态差异及日本文蛤的物种有效性,采用多变量形态度量,结合传统分类方法,获得日本文蛤和中国大陆文蛤属2种贝类8个形态比例性状,并做单因素方差分析、聚类分析、主成分分析、判别分析及Mantel检验。结果表明,(1) 单因子方差分析显示,日本文蛤与中国大陆文蛤属2种贝类,在8个比例性状中存在着5~8个显著差异(P<0.05);(2) 聚类分析表明,6个文蛤地理种群距离相近,且呈现南北分别聚为一类,而日本文蛤与长乐丽文蛤相近;(3) 主成分分析构建了3个主成分,其贡献率分别为34.88%、18.61%、16.89%,累积贡献率为70.38%,三维主成分散布图进一步表明日本文蛤与丽文蛤均独立于文蛤不同地理种群重叠区之外;(4) 判别分析构建了8个判别函数,判别准确率P₁为39.09%~100%,P₂为47.06%~100%,日本文蛤与中国大陆文蛤属2种贝类的综合判别率为70.60%,其中日本文蛤判别准确率为100%,丽文蛤判别准确率高于91.67%;(5) Mantel检验结果表明,各种群间的地理距离与欧氏距离之间存在显著相关性(r=0.623 7, P<0.01)。研究认为,日本文蛤属于丽文蛤,与长乐丽文蛤属于同一种不同地理种群;根据MAYR等提出的75%规则,8个比例性状中有5个性状大于1.28,两个丽文蛤群体已达到亚种水平。     

基于线粒体Cyt b基因的虾夷扇贝群体遗传结构分析

本研究利用线粒体细胞色素b(Cyt b)基因标记对虾夷扇贝(Patinopecten yessoensis)6个群体(长岛底播增殖群、海洋岛底播增殖群、獐子岛底播增殖群、旅顺自然群、"獐子红"人工选育群以及日本青森陆奥湾群)进行种质状况评估,研究结果表明,6个群体120个个体的Cyt b基因序列共检测到20种单倍型,其中"獐子红"人工选育群单倍型最少,日本群体单倍型最为丰富,两者单倍型多样性指数分别为0.10000和0.88400。分子方差分析(AMOVA)发现,日本群体与中国群体间变异百分比为15.34%,明显高于作为一个基因池时群体间遗传变异水平;就中国组群而言,其83.41%的遗传变异来自于群体内部,组内群体间的变异只占1.52%,说明中国群体个体间的遗传变异远大于群体间的遗传变异。F_(st)分析显示,中国群体与日本群体之间发生了中等水平的遗传分化(0.07455~0.17895,Fst0.05)。以遗传距离矩阵构建群体间分子系统树(UPGMA树),拓扑结构图显示中国5个群体先聚为一支,再与日本群体聚为一支。由此可见,中国养殖区的虾夷扇贝与日本原产地群体间已出现明显的遗传分化,且虾夷扇贝中国群体的遗传多样性处于较低水平。本研究结果可为虾夷扇贝的种质资源保护与可持续开发利用提供理论依据。     

缢蛏选育系F5的生长优势比较及育种效应分析

以6个缢蛏(Sinonovacula constricta)自然群体(浙江象山群体、浙江乐清群体、福建霞浦群体、福建长乐群体、江苏射阳群体和上海崇明群体)为材料,构建基础群体F_0,采用群体选育方法进行多代连续选育(选择强度2.063),比较了选育系F_5与对照群体的生长差异,并估计F_5的选择反应、现实遗传力和遗传获得。结果表明,F_5的卵径及受精率与对照组无显著差异(P0.05),但F_5的变态率、存活率及后期壳长生长明显优于对照组(P0.05);7~360日龄F_5壳长的选择反应、现实遗传力与遗传获得的变化范围分别为0.30~0.78,0.14~0.37和4.83%~42.18%,平均为(0.49±0.06),(0.23±0.08)和(26.49±11.73)%。研究结果表明,对缢蛏的连续多代选育是有效的,可以明显提高其存活能力和主要经济性状。     

Low genetic diversity of cultivated spotted hard clam (Meretrix petechialis) in Taiwan

The aquaculture of spotted hard clams, Meretrix petechialis, is a well‐developed industry in Taiwan. Spats have been produced for decades through artificial propagation using broodstocks selected from neighbouring culture farms on the basis of size and maturity, and the produced spats are resold to these culture farms. Although mass mortality occurs frequently in this practice, the effect of inbreeding depression has never been evaluated. Therefore, genetic diversity of 173 spotted hard clams from museums, two culture farms and three purchased populations was examined in this study. Phylogenetic analyses, based on either COI or cyt b fragments, indicated a division into lineages A and B among the samples. Cultured clams, except for one clustered with M. lusoria, museum specimens, and purchased samples from Hsinchu were all grouped into lineage A. The remaining two purchased populations were placed in both lineages. Compared with cultured clams from the Chinese coast in a previous study, our results exhibited a much lower haplotype (0.354 vs. 0.900) and nucleotide diversity (0.00113 vs. 0.00543). However, whether the loss of genetic variation is a consequence of inbreeding or the founder effect in the initial small broodstocks is unclear. The introduction of broodstocks from northern Vietnam and southern China may facilitate the management of genetic diversity. Environmental factors that potentially cause mass mortality require further investigation.     

Loss of genetic variability in the captive stocks of tambaqui,Colossoma macropomum (Cuvier, 1818), at breeding centres in Brazil,and their divergence from wild populations

The loss of variability in farmed populations and the risks of interactions with wild populations support the need for the genetic monitoring of species farmed throughout the world. In Brazil, the tambaqui is the most widely farmed native fish species. Despite this, there are no data on the pedigree of the farmed stocks, and the potential for interactions with wild populations in the Amazon basin has raised concerns with regard to the genetic variability of these stocks. The present study analysed sequences of the mitochondrial Control Region and 12 microsatellites to characterize the genetic variability of seven historically important commercial tambaqui breeding centres located in four different regions of Brazil, and compared these sequences with those obtained from individuals collected from a wild population. High levels of genetic diversity were found in the wild population, whereas genetic diversity was reduced in both markers in most captive populations, except for the broodstock located near the Amazon River. High F_ST and D_EST indices were recorded between the wild population and most of the captive stocks analysed. The drastic reduction in genetic diversity found in most captive stocks and the difference between these stocks and the wild population may have been the result of the small size of the founding populations and the absence of breeding management. The renewal of the broodstocks and the application of breeding management techniques are recommended. In the Amazon region, in addition, the use of broodstocks that are genetically very different from local wild populations should be avoided.     

福建沿海文蛤产地和暂养地贝类素毒化状况

采集福建沿海文蛤产地，暂养地的文蛤，结合分析其所生长的个体情况，检测其DSP和PSP，结果表明：福建沿海文蛤产地和暂养地未出现的DSP，PSP毒化状况。     

Genetic characterizations of Mactra veneriformis (Bivalve) along the Chinese coast using ISSR-PCR markers

The genetic structure of seven different populations of the surf clam Mactra veneriformes along the coast of China was investigated by Inter-Simple Sequence Repeats (ISSR) fingerprinting of 210 individual clams. Of the 240 ISSR loci tested, 235 (97.9%) were polymorphic. We found a clear tendency for higher F_ST values and lower gene flow levels between the populations with increasing geographical separation. The seven different geographic populations can be divided into three subgroups: Liaoning, Qingdao/Lianyungang, and Ningbo based on the UPGMA dendrogram of Nei's genetic distance. These results indicated that isolation of geographic distance played an important role in population differentiation.     

Influence of Congeneric Aquaculture on Hard Clam (Mercenaria spp.) Population Genetic Structure

Throughout their range, hard clams of the genus Mercenaria support important commercial fisheries, and hard clam aquaculture is rapidly developing in several regions, including Florida, USA. Commercial hard clam aquaculture in Florida waters originated in the Indian River Lagoon during the late 1970s, but by the early 1990s the focus of the industry had shifted to Cedar Key on the west coast of the state. There, the species Mercenaria campechiensis predominates the natural hard clam population, whereas Mercenaria mercenaria is predominant in the local aquaculture industry. The two species hybridize extensively. The present study was conducted to estimate the genetic implications of M. mercenaria aquaculture on the natural population of M. campechiensis that occupies Cedar Key waters. We sampled a variety of marine and estuarine habitats surrounding Cedar Key and collected 257 hard clams for analysis of species-specific diagnostic allozyme loci, age, and the presence and stage of gonadal neoplasia. Results indicate that the composition of the hard clam population has changed since the advent of aquaculture (i.e., post-aquaculture). Members of the species M. mercenaria were practically nonexistent prior to the 1993 initiation of aquaculture in the area but increased significantly in abundance post-aquaculture, as did hybrid hard clams. There was no significant difference in the abundance of M. campechiensis pre- versus post-aquaculture. All genotype classes had a high incidence (>80%) of gonadal neoplasia, although it is not clear if this high incidence is a reflection of the introduction of aquaculture into the area or if neoplasia was a common feature of the population prior to 1993. Regardless, this finding is not consistent with previous reports that neoplasia is more common in hybrid hard clams. Overall, the results of this study provide clear evidence that culture of M. mercenaria can influence the genotype composition of naturally occurring congeneric populations in the vicinity of the culture operation. The long-term implications of that influence remain to be seen.     

Genetic population structure of the Pacific bluefin tuna Thunnus orientalis and the yellowfin tuna Thunnus albacares in the North Pacific Ocean

The genetic population structure of the Pacific bluefin tuna (PBF) Thunnus orientalis and the yellowfin tuna (YFT) T. albacares in the North Pacific Ocean was investigated. The polymorphism of microsatellite (SSR) loci and sequences of mitochondrial DNA control region (mtCR) were analyzed for 71 samples of PBF from Japan and Mexico and 45 samples of YFT from Japan and Panama. In the SSR analyses, both single-locus (?0.010 to 0.008 in PBF and ?0.023 to 0.020 in YFT) and global multilocus (0.003 in PBF and ?0.002 in YFT) F _ST values among the geographic populations were low and not significant in these species. In the mtCR analyses, neither the neighbor-joining tree nor the minimum spanning network showed genetic differentiation among the geographic populations in each species. The pairwise F _ST values among the geographic populations of them (?0.005 in PBF and ?0.020 to ?0.014 in YFT) were low and not significant. Our SSR and mtCR data suggested that genetic differentiations were not evident among the eastern and western populations in the North Pacific Ocean either in PBF or in YFT. Mismatch distributions, demographic parameters, and neutrality tests suggested that sudden population expansion of PBF and YFT in the North Pacific Ocean occurred 628,000–731,000 and 450,000–525,000 years ago, respectively.     

河蚬微卫星引物筛选及洪泽湖野生群体遗传结构分析

利用磁珠富集法筛选了河蚬10对中高度多态性的微卫星引物,并分析了洪泽湖河蚬4个野生群体的遗传结构.结果表明,每个群体至少有4个位点经Bonferroni校正后显示杂合不足,显著偏离了Hardy -Weinberg平衡(P＜0.013)；4个群体平均期望杂合度均大于0.752,显示出较高的遗传多样性水平,蒋坝、临淮群体遗传多样性高于高良涧和老子山群体；突变-漂移平衡分析结果显示,4个群体在IAM模型下偏离了突变-漂移平衡,高良涧群体在TPM模型下偏离了突变-漂移平衡,且表现杂合过剩,说明少数群体即将或曾经经历瓶颈效应,群体数量已出现波动；群体间AMOVA分析表明,洪泽湖河蚬群体间遗传分化程度较低(FST=0.017 7＜0.05),仅有1.77％的变异来自群体间,并没有形成显著的遗传结构,在种质资源保护和管理上可视作一个单元,这为河蚬种质资源保护和合理开发利用提供了理论指导.     

基于SSR和ISSR标记对江苏大竹蛏野生群体和人工增殖群体的联合分析

为探索人工增殖活动对本地大竹蛏(Solen grandis)种质资源带来的影响,采用SSR及ISSR分子标记手段对江苏大竹蛏野生群体与人工增殖群体的遗传多样性及遗传结构进行了联合分析。筛选的14对SSR引物扩增获得多态性位点150个(PPB=93.16%),Nei's基因多样性指数和平均Shannon信息指数分别为0.134 2和0.253 5;筛选的10条ISSR引物获得多态性位点85个(PPB=91.93%),Nei's基因多样性指数和平均Shannon信息指数分别为0.131 0和0.230 2。两种方法分析得到野生群体的遗传多样性参数均显著高于人工增殖群体,但两群体间并未产生明显的遗传分化。实验结果表明,江苏沿海大竹蛏群体的遗传多样性水平较高,人工增殖群体的遗传多样性虽有所下降,但并未导致该地区大竹蛏种质资源遗传结构的显著改变。因此人工增养殖活动仍然能够作为补充大竹蛏资源的主要手段,但应探索采用高效生态的增养殖模式,对大竹蛏的种质资源进行合理的开发与利用。     

Cu2+对文蛤红壳色选育系及自然群体抗氧化能力的影响

Cu²⁺作为海洋重金属污染的主要污染物之一,具有来源广、易残留、易食物链富集等特点,是海洋贝类养殖业潜在的生态危机和经济危机。为查明江苏文蛤自然群体及红壳色选育系对重金属Cu²⁺耐受能力,设置不同质量浓度Cu²⁺对文蛤红壳色选育系和自然群体进行胁迫试验,研究Cu²⁺对文蛤超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性以及Cu/Zn-SOD基因相对表达量的影响。试验结果显示:(1)在相同质量浓度Cu²⁺条件下,红壳色选育系与自然群体存活率差异不显著(P>0.05)。(2)随着Cu²⁺质量浓度增大,两组文蛤的超氧化物歧化酶和过氧化氢酶活性变化共同表现出相应质量浓度—效应关系,超氧化物歧化酶活性变化呈线性上升趋势,而过氧化氢酶活性变化呈先抑制后诱导的趋势,两种酶活性变化差异显著(P<0.05)。(3)Cu/Zn-SOD基因表达变化与超氧化物歧化酶活性变化一致,与Cu²⁺质量浓度呈正相关。(4)红壳色选育系响应Cu²⁺抗氧化性要优于自然群体。本试验结果将对文蛤抗逆性选育及新品种开发提供科学参考。