共查询到20条相似文献，搜索用时 78 毫秒
1.
为了评估长牡蛎(Crassostrea gigas) 2个壳长性状(掌心形)快速生长选育群体(LY2-K4、LY2-K7)、1个壳高性状(速生型)快速生长选育群体(LY2-K11)和6个野生群体(QHD、LS、HD、ZH、WD、KTD)的遗传多样性和遗传结构, 用21对多态性丰富的微卫星引物对9个长牡蛎群体的269个个体进行了遗传分析。结果显示: 21个微卫星位点共检测出了460个等位基因(Na),平均等位基因数为21.905; 21个微卫星位点的多态信息含量(PIC)均大于0.5, 具有高度遗传多态性; 选育群体LY2-K11的遗传多样性最低(Na=13, I=2.128,He=0.831, PIC=0.825), 野生群体KTD的遗传多样性最高(Na=29,I=3.112, He=0.941, PIC=0. 938); 189个群体位点组合有66%偏离哈代-温伯格平衡, 表明这些群体存在一定程度的杂合子缺失; 9个群体间的遗传分化指数(Fst)为0.012~0.064, 处于较低的遗传分化水平; AMOVA分析显示遗传变异主要来自于个体内; PCoA分析结果与UPGMA聚类树一致, LY2-K11群体单独聚为一类, QHD和HD群体聚为一类, 其他6个群体聚为一类。综上所述, 长牡蛎3个选育群体和6个野生群体遗传多样性均较高, 遗传分化水平较低; 选育群体LY2-K11多样性略有下降, 选育过程中应保证亲本的数量及质量, 防止因近交衰退造成遗传多样性降低, 苗种抗逆性变差。该结果将为长牡蛎新品种的选育和野生种质资源的保护提供科学指导。 相似文献
2.
真江蓠是原产于西北太平洋的重要经济红藻。我们利用10对微卫星引物检测中国黄渤海地区真江蓠的群体遗传多样性和结构。10个微卫星位点在12个群体中共检测到65个等位基因，每个位点的等位基因（Na）为1~28，有效等位基因（Ne）为1.0~9.6。每个群体的平均等位基因（Na）、平均有效等位基因（Ne）、平均香浓指数（I）、平均观察杂合度（Ho）和平均预期杂合度（He）分别为2.4、1.6、0.419、0.133和0.227，显示较低的群体遗传多样性。中国黄渤海12个真江蓠群体间遗传分化较大（Fst=0.398 7），基因流有限（Nm=0.377 1），近交系数为正（Fis=0.391 3，Fit=0.634 0），表明可能存在近交和杂合子缺失现象。Structure和UPGMA系统进化分析一致将12个群体分为两个遗传组，并在黑石礁群体（HS）和石岛群体（SD）中发现明显的遗传混杂现象。AMOVA分析显示遗传变异主要来自于群体内（73.27%）。该研究可为黄渤海地区真江蓠自然资源保护和管理提供科学依据。 相似文献
3.
用10 对AFLP 选择性扩增引物, 对4 种壳色华贵栉孔扇贝(Chlamys nobilis)选育系的F1代群体(每种壳色30 个, 共120 个个体)进行了遗传多样性分析, 共扩增出414 个位点, 多态性位点352 个, 比例为85.02%; 紫顶枣褐、枣褐、紫白、橘黄4 种壳色群体多态性位点比例分别为72.83%、86.04%、83.47%、67.35%; Nei’s基因多样性指数(H)分别为0.3071、0.3494、0.3358、0.3077; Shannon’s 信息指数(I)分别为0.4607、0.5139、0.4987、0.4525。4 个群体间的平均遗传分化系数(Gst)为0.1739, 遗传杂合度(He)为0.3954, 遗传距离(D)变化范围在0.1194～0.1720 之间; 聚类分析表明, 4 种壳色选育系间的亲缘关系由近及远依次为紫白、枣褐、橘黄和紫顶枣褐壳色。研究表明, 四种壳色选育系均具有较高的遗传多样性, 各壳色群体间存在一定分化, 继续选育潜力大。 相似文献
4.
我国东南沿海5个波纹巴非蛤(Paphia undulata)地理群体的形态差异分析 总被引：1，自引：0，他引：1
采用聚类分析、主成分分析和判别分析3种分析方法,对我国东南沿海5个野生波纹巴非蛤群体10个形态性状进行比较研究。聚类分析和主成分分析结果表明,广东东莞与福建厦门群体、广东湛江与海南海口群体的形态最为接近,广西北海群体的趋异程度最大。主成分分析构建了3个主成分,贡献率:主成分1为23.237%,主成分2为16.109%,主成分3为13.009%,累计贡献率为52.355%。判别分析结果表明,5群体间形态差异显著(P0.01)。建立了5群体的判别函数,判别准确率P1为47.1%—80.0%,P2为45.7%—80.0%,5群体的综合判别率为63.8%。Mantel检验结果表明欧氏距离与地理直线距离无明显相关性(r=0.0822,P=0.3820)。广西北海群体明显地与其它4个地方分开,可能已形成一个新的亚种。本研究可为我国巴非蛤种质资源保护及遗传育种提供依据。 相似文献
5.
凡纳滨对虾的主要选育目标分为两个方面: 一是培育具有较强抗病、抗逆性的“高抗系”(GK),二是培育具有快速生长特性的“快大系”(KD)。然而, 国内缺少针对这两个选育群体的遗传多样性特别是基因组近交水平的调查分析研究。基于液相芯片“黄海芯1号”(55 K SNP)的基因分型数据, 首次分析了GK (1 064尾个体)和KD (564尾个体)选育群体的遗传结构和遗传多样性, 调查了连续性纯合片段(ROH)的基因组分布特征, 并重点评估了两个群体的基因组近交水平。PCA及进化树分析表明GK及KD群体可明确分层, 亲缘关系热图表明KD群体内个体间的亲缘关系比GK群体更近。GK群体包括的家系数量更多, 导致其遗传多样性高于KD群体; 两群体间的Fst为0.09, 存在中等遗传分化。GK和KD群体每个ROH的平均长度分别为(1.70±0.34) Mb和(1.65±0.38) Mb, 每个样本ROH的平均数量分别为1.98±1.30和2.07±1.37。GK和KD群体0.8~1.25 Mb长度的ROH占比分别为11.41%和19.17%, 表明KD群体的选育历史比GK群体更长。两个群体>2.25 Mb长度的ROH片段占比分别为10.26和9.74%, 表明两个群体短期内未发生近亲交配。七种基因组近交系数评估结果表明, KD群体的近交水平高于GK群体。不依赖基础群体等位基因频率的FROH和FHOM方法可准确地评价育种群体的真实近交水平, 而FVR1、FYA1和FLH1等依赖基础群体等位基因频率的方法可以用来比较群体及个体间的相对近交水平。上述结果为准确地评估育种群体的近交水平和优化育种方案提供了重要参考依据。 相似文献
6.
波纹唇鱼mtDNA D-loop 序列变异分析 总被引：2，自引：1，他引：1
为研究波纹唇鱼(Cheilinus undulatus)线粒体D-loop 序列遗传多样性, 作者采用聚合酶链式反应和克隆技术对海波纹唇鱼群体(n=25)的mtDNA D-loop 序列进行克隆和测序, 获得长度大约为1 400 bp的产物。用ClustalX 软件进行排序比较, 将结果导入MEGA5.0, 结果显示出在这25 尾个体中, 共检测出66 个变异位点, 包括0 个碱基缺失, 4 个碱基插入, 59 转换位点, 2 颠换位点及1 个转换和颠换同时存在的位点。并用MEGA5.0 软件构建该群25 尾个体的NJ 和UPGMA 系统树。由DNASP 软件计算出该波纹唇鱼群体的多态位点数(S)为62, 核苷酸多样性(Pi)为0.00606, 平均核苷酸差异数为6.907。结果表明波纹唇鱼群体的mtDNA-loop 基因个体差异程度不明显。 相似文献
7.
采用12个多态性微卫星标记对方斑东风螺(Babylonia areolata)泰国选育系TF4~TF6连续3代选育群体的遗传多样性与遗传结构进行了分析。3个群体的多态信息含量分别为0.730、0.717和0.708,均高于0.5,表现出较高的多态性。平均等位基因数(A)、有效等位基因数(Ae)、观测杂合度(Ho)、期望杂合度(He)和Shannon’s信息指数(I)的变化范围分别为11.667~12.583、6.334~6.915、0.658~0.672、0.737~0.787和1.837~2.003,整体呈降低趋势,但差异并不显著(P>0.05)。分子方差分析结果显示,群体间的遗传变异仅占总变异的0.95%;群体间的遗传分化系数(Fst)介于0.00569~0.01324,处于低等分化水平(Fst<0.05)。主坐标分析和STRUCTURE分析结果显示,3个群体呈现出相似的遗传背景和遗传结构。以上研究结果表明,经过连续多代的人工选育,方斑东风螺选育群体保持着较高的遗传多样性水平,遗传变异和遗传分化水平较低,遗传结构趋于稳定,仍具有较高的遗传选育潜力。 相似文献
8.
采用55个随机引物对西施舌(Coelomactra antiquata)5个群体, 即长乐(CL)、启东(QD)、连云港(LYG)、胶南(JN)和北海(BH)群体进行RAPD 扩增。用PopGen(Version1.32)软件进行遗传多样性分析。结果共筛选出12个重复性好的引物, 得到88条清晰稳定的条带, 扩增片段在100 bp～3 000 bp之间, 其中引物S299扩增的600 bp片段为长乐群体特有。多态位点比例为62.07%～78.26%(JN、LYG、BH、QD、CL群体分别为78.26%、77.05%、72.58%、70.05%、62.07%), Shannon指数为0.210 5～0.312 3。群体间遗传距离为0.068 3～0.223 9,其中长乐群体与其余4个群体间的遗传距离为0.182 7～0.223 9, 4个非长乐群体的遗传距离为0.068 3～0.136 7。群体间遗传分化系数(Fst)为 0.313 01(P<0.05), 表明在整个遗传变异中群体间占31.30%。CL群体与QD, BH, JN, LYG群体间的遗传分化系数(Gst)分别为0.364 9,0.344 8, 0.325 0, 0.309 0;而非长乐群体之间的遗传分化系数为0.148 2～0.240 3;以上数据显示长乐群体遗传分化最大。聚类结果显示, 启东和胶南群体首先聚为一支, 然后与北海群体聚在一起, 再和连云港群体相聚; 而长乐群体则单独形成一支。 相似文献
9.
为比较中国不同海域口虾蛄(Oratosqilla oratoria)群体的遗传特性, 作者对采自皮口、绥中、青岛和广州4 个海域的口虾蛄群体的线粒体COI基因序列进行扩增和测序, 比较并分析了其遗传多样性和系统进化关系。获得585bp 的口虾蛄线粒体COI基因序列, 发现变异位点54 个, 占总位点数的9.2%。COI基因序列A+T 含量(64.8%)显著高于G+T 含量(35.2%), 符合节肢动物线粒体DNA 碱基组成的特点。转换与颠换的平均比值是7.84, 碱基替换未达到饱和。100 个样本的线粒体COI基因序列共定义35 个单倍型, 单倍型多样性(Hd)为0.9162, 平均核苷酸多样性(π)为0.0203。4 个群体均具有高的单倍型多样性和低的核苷酸多样性的特点, 说明4 个海域口虾蛄的遗传多样性均处于中等水平, 但广州海域的遗传多样性水平最高。AMOVA 分析表明, 来自于群体间的遗传差异(84.53%)明显高于来自群体内的差异(15.47%)。遗传分化系数(Fst)表明皮口、绥中、青岛3 个海域间几乎没有发生分化(Fst<0), 而广州海域口虾蛄遗传分化较大。从GenBank 上下载了19 条粤东海域口虾蛄的同源序列与本实验获得序列共同构建NJ 系统发育树, 结果显示皮口、绥中、青岛聚为一支, 广州和粤东(深圳和汕尾)聚为另一支。单倍型系统发育树和单倍型进化网络关系图均显示出广州海域口虾蛄群体较大的遗传分化。 相似文献
10.
4个缢蛏群体遗传多样性和系统发生关系的微卫星分析 总被引：2，自引：0，他引：2
采用12个微卫星分子标记,对4个不同缢蛏(Sinonovacula Constricta)群体: 福建云霄群体、广东湛江群体、天津塘沽群体以及浙江乐清湾群体进行了遗传多样性和系统发生关系的分析。研究结果显示, 12个微卫星共有46个等位基因, 4个缢蛏群体的平均观测等位基因数(Ao)、平均观测杂合度(Ho)、平均期望杂合度(He)和平均多态信息含量(PIC)分别为3.25～3.50、0.59～0.74、0.55～0.58 和0.46～0.50。说明4个缢蛏群体遗传多样性处于中等多态。UPGMA聚类分析表明:乐清湾群体、天津塘沽群体间的遗传距离最小, 亲缘关系最近, 首先聚为一支, 福建云霄群体和广东湛江群体聚为另一支。群体的F-统计量(Fst)为0.07, 表明缢蛏群体分化很微弱。 相似文献
11.
经济海藻繁育、养殖及综合利用是海洋农牧业及工业的重要组成部分。20世纪经过几代人的努力，我国在海带、紫菜、裙带菜及龙须菜的繁育、养殖关键技术等方面成功取得突破，为这些海藻的产业化提供坚实的保障，为我国成为世界海藻大国奠定了基础。海藻养殖产业为人们提供了食品、藻胶及其它丰富的产品，这包括保健品、功能食品、化妆品及药物等。海藻养殖产业也对人类经济、社会的发展起到重要作用，通过吸收环境中的二氧化碳、氮和磷，为海洋生态环境的改善发挥了重要作用。本文对我国海藻繁育、养殖及综合开发的历程进行简要回顾，对当前我国、中国科学院海洋研究海藻研究与应用进行了总结，对海藻研究发展的未来进行了展望；适应海藻产业从量向质的方向转变，同时兼顾生态环境效益，为我国海藻研发及应用提供参考。 相似文献
12.
The aim of the present study was to investigate seasonal and spatial patterns of soil oxygen consumption, nitrification, denitrification and fluxes of dissolved inorganic nitrogen (DIN) in a tidal salt marsh of the Lagoon of Venice, Italy. In the salt marsh, intact soil cores including overlying water were collected monthly at high tide from April to October in salt marsh creeks and in areas covered by the dominant vegetation, Limonium serotinum. In May, cores were also collected in areas with vegetation dominated by Juncus maritimus and Halimione portulacoides. In laboratory incubations at in situ temperature in the dark, flux rates of oxygen and DIN were monitored in the overlying water of the intact cores. 15N-nitrate was added to the overlying water and nitrification and denitrification were measured using isotope-dilution and -pairing techniques. The results show that highest soil oxygen consumption coincided with the highest water temperature in June and July. The highest denitrification rates were recorded in spring and autumn coinciding with the highest nitrate concentrations. Soil oxygen consumption and nitrification rates differed between sampling sites, but denitrification rates were similar among the different vegetation types. The highest rates were recorded in areas covered with L. serotinum. Burrowing soil macrofauna enhanced oxygen consumption, nitrification and denitrification in April and May. The data presented in this study indicate high temporal as well as spatial variations in the flux of oxygen and DIN, and nitrogen transformations in the tidal salt marshes of the Venice lagoon during the growth season. The results identify the salt marshes of the Venice lagoon as being metabolically very active ecosystems with a high capacity to process nitrogen. 相似文献
13.
通过人工授精技术对牙鲆(Paralichthys olivaceus )和夏鲆( Paralichthys dentatus )进行了正反交及回交实验,并比较了正反交、回交子代的胚胎发育时序和仔稚幼鱼的生长.结果表明:孵化水温18.0±0.5℃下,初孵仔鱼破膜用时为:牙鲆41 h,正交鲆47 h,回交牙鲆42 h30 min,回交夏鲆44 h;16.5±0.5℃下,夏鲆61 h 40 min,反交鲆66 h.正交及两组回交子代在胚胎期均可正常发育.反交子代卵裂期出现异常,仅少数胚胎可以孵化.胚胎孵化后,在1~64日的培养过程中,反交鲆于3~4 d 内全部死亡,回交牙鲆发育至18日龄时全部死亡.正交鲆和回交夏鲆可正常发育,与牙鲆没有明显差别 相似文献
14.
克隆获得缢蛏(Sinonovacula constricta)谷胱甘肽S-转移酶(Sc-GSTσ)和热休克蛋白90(Sc-HSP90)基因的cDNA全长，分析了它们的组织表达差异及其在氨氮胁迫下的表达特征。结果表明，Sc-GSTσ的全长cDNA为1 414 bp，含有639 bp的开放阅读框(Open Reading Frame，ORF)，编码212个氨基酸，Sc-GSTσ氨基酸序列与其他物种的GST氨基酸序列同源性为31.88%～43.40%；而Sc-HSP90的全长cDNA为2 752 bp，ORF为2 181 bp，编码726个氨基酸，其氨基酸序列与其他物种HSP90的氨基酸序列同源性为76.77%～87.05%。荧光定量PCR分析发现，Sc-GSTσ和Sc-HSP90在缢蛏各组织中均有表达，两者均在肝胰腺中表达量最高。氨氮胁迫后，Sc-GSTσ和Sc-HSP90 mRNA在肝胰腺中表达均显著上调(p<0.05)，表明氨氮胁迫引起机体的应激反应，2个基因可能参与机体解毒或防御过程。但胁迫后期表达量下降推测是机体的防御能力有限，不足以完全保护宿主免受应激诱导的细胞损伤。 相似文献
15.
为了探究经过15年种间竞争后的外来无瓣海桑(Sonneratia apetala)与乡土红树植物秋茄(Kandelia obovata)的群落现状与发展趋势,采用样方法对福建省厦门市同安湾典型红树林群落特征开展实地研究。结果表明:(1)无瓣海桑是无瓣海桑群落中的优势种,而秋茄仅在该群落北侧与无瓣海桑少量混交,秋茄+无瓣海桑群落为种植秋茄和无瓣海桑的茂密混交林;(2)调查幼苗天然更新情况中发现,在两个群落中秋茄均有幼苗自然生长,但均未发现无瓣海桑幼苗;(3)生长状况的调查发现,无瓣海桑长势较秋茄差,其倒伏数量和倒伏程度明显比秋茄严重;(4)无瓣海桑在秋茄+无瓣海桑群落中的生长状况优于在无瓣海桑群落,倒伏程度较轻。综上可见,无瓣海桑在福建省厦门市该研究样地及其周边更新成林和扩散困难,未有入侵秋茄群落的优势;无瓣海桑在风浪环境下,较秋茄更易出现倒伏和枯死等不可逆生长现象;红树林种植过程中采用"外来种+乡土种"的模式,可提高整个林分的抗风浪能力,但需注意种植布局规格的合理性,可避免外来速生快长种与乡土种紧邻混交产生较大的种间竞争,减小对乡土种生长的影响。 相似文献
16.
Vertical and horizontal distribution of meiofauna in mangrove sediments in Transkei, southern Africa
The depth-distribution profiles of meiofauna in four transects in the Mngazana River, Transkei were studied during summer 1980. Highest densities [±1000(100 cm3)−1] were encountered within the top 10 cm of the sediment. Nematodes dominated (80%) and the remainder was made up of ciliates, oligochaetes, gastrotrichs, and low numbers of polychaetes, copepods, kinorhynchs and various crustacean larvae. Among chemical parameters Eh correlated most consistantly with distribution, particularly at the lower tidal levels. Temperature and pH appeared to be of lesser importance. The maximum estimated depth of penetration was on average 72 cm at the HW levels; 32 at MW and 23 at LW. The mean dry biomass was estimated at 1073 mg m−2; 941 mg m−2 and 196 mg m−2 at these tidal levels respectively. The importance of preliminary studies designed to estimate the depth distribution of meiofauna is discussed. 相似文献
17.
Copper and iron concentrations in three brown algae, Ascophyllum nodosum, Fucus vesiculosus and Laminaria digitata (and additionally Mn in L. digitata) from the Irish west coast were determined using flame atomic absorption spectrophotometry. Metal concentrations in the three species were indicative of prevailing bioavailable metal concentrations in situ but varied greatly between functional tissue parts, between sites and over time. Cu concentrations in actively growing tips of A. nodosum decreased over a 4-month period during autumn/winter, while Fe concentrations increased. Both Fe and Cu concentrations in different thallus sections of A. nodosum and F. vesiculosus increased with increasing age of thallus part in a clean site, but there was no consistent trend for F. vesiculosus from an industrialized site. Within sites, concentrations of all Cu and Fe were similar in both fucoids, but concentrations at the industrialized site were about twice as high as at the pristine site. In L. digitata, all three metals were highest in holdfasts, but had distinctly different distribution patterns in stipes and blade sections, which were most likely related to growth pattern and tissue function. Fe was lowest in meristematic and young blade regions, suggesting small-scale Fe limitation in actively growing tissue. Mn concentrations were higher in distal blade sections than in stipes, and Cu concentrations were highest in meristematic and young thallus parts. 相似文献
18.
Four species in the genus Navicula were isolated using the serial dilution method. Based on scanning electron microscopy(SEM) and sequence comparisons of two segments of genes(small ribosomal subunit and large subunit of Rubisco), the species were identified as Navicula perminuta, N. pseudacceptata, N. vara, and N. rhynchocephala. Based on phylogenetic analysis and culture trials, there was a close relationship between N. perminuta and N. vara. Growth of these species was evaluated using measurements of optical density at 680 nm(OD680) under various environmental factors. Results showed that the optimum culture conditions were 25℃, 50–100 μmol photons m-2 s-1, pH 8.0, and salinities from 25 to 30. However, the favorable salinity for N. perminuta was surprisingly high at 35. Nutrient requirement analysis demonstrated that growth of Navicula depended on the availability of SiO32-. Their relative growth rates(RGR) peaked at the highest tested level(0.25 mmol/L). The optimal concentrations of NO3- and PO43- were 3.6 mmol/L and 0.18 mmol/L, respectively. Culture of these Navicula species for abalone or sea cucumber aquaculture should take these factors into consideration. 相似文献
19.
ＰｒｏｐａｇａｔｉｏｎａｎｄｇｒｏｗｔｈｏｆＰｏｎｎｏｔｈｅｒｅｓｐｈｏｌａｄｉｓｌｉｖｉｎｇｉｎｍａｎｔｌｅｃａｖｉｔｙｏｆＨｉａｔｕｌａａｃｕｔａＹａｎｇＹａｏｃｏｎｇ,ＬｉＦｕｘｕｅ１,ＣａｉＬｉｚｈｅ（ＲｅｃｅｉｖｅｄＡｐｒｉｌ２４,１９９７... 相似文献
20.
Conjugation of phenolic xenobiotics and metabolites through sulfation and glucuronidation is an important biotransformation pathway. Sulfotransferases (SULT) are generally considered non-inducible, while some UDP-glucuronosyltransferase (UGT) isoenzymes are co-induced with cytochrome P450-1A by Ah-receptor ligands. To test these assumptions for two fish species, we measured sulfation and glucuronidation of 9-hydroxybenzo[a]pyrene in 3-methylcholanthrene (3-MC) treated channel catfish (Ictalurus punctatus) and in mummichog (Fundulus heteroclitus) from the creosote contaminated Atlantic Wood site in the Elizabeth River, VA. The results show a significant induction of both UGT and SULT activity in 3-MC treated catfish, linked to the expected induction of EROD activity. In mummichog, significant induction of UGT was measured at the contaminated site over the reference site (King's Creek, VA), as well as extremely low SULT activities at both sites. Western blots, using a polyclonal antibody for catfish phenol-type SULT, confirmed the absence of phenol-type SULT in mummichog. Residual, though slightly inducible, SULT activity may be attributed to other SULT isoforms. 相似文献