Germplasm of breeding Pseudosciaena crocea as revealed by microsatellite markers

The germplasm of breeding large yellow croaker （Pseudosciaena crocea Richardson） was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min - Yue stocks and two hybrid groups, as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity. The value of pair- wise differentiation coefficient（ FST ） was only 13. 1% between Daiqu and Min -Yue stocks, demonstrating the low level of differentiation and a close relationship. However, STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different populations of the same species with distinct genetic structures. Examinations of individual admixture showed that Min - Yue stock had been contaminated by alien individuals. Moreover, the genetic structures of the two hybrid groups resembled those of their parents, especially affected more by their female parents. Finally, the values of average observed heterozygosity between parents and their ascendants were compared and tested, as a result of no detectable differences （P 〉 0. 05）.     

黑脊倒刺鲤线粒体DNA多样性分析

黑脊倒刺喜巴（Spinibarbus caldwelli）是分布于中国南方各水系,具有重要经济价值鱼类。文中对来自赣江、九龙江、漓江等3水系的瑞金、长泰、桂林等3个黑脊倒刺喜巴种群共61个样品的线粒体DNA细胞色素b基因（mtDNA cyt b）进行PCR扩增和测序。对序列进行分析。结果发现,在全长（1141bp）cyt b共检测到45个变异位点,61个样品分属16个单倍型,与其它鲤科鱼类比较,黑脊倒刺钯的遗传多样性水平比较低。分子方差分析（AMOVA）及系统发育分析显示,瑞金和长求种群没有显著遗传差异,而它们与桂林种群存在显著遗传分化,提示黑脊倒刺啻巴可能存在多个地理种群。     

Genetic diversity analysis with ISSR PCR on green algae <Emphasis Type="Italic">Chlorella vulgaris</Emphasis> and <Emphasis Type="Italic">Chlorella pyrenoidosa</Emphasis>

In the present study, genetic polymorphism and diversity in unicellular clones of Chlorella vulgaris Beijerinck and Chlorella pyrenoidosa Chick were studied with Inter Simple Sequence Repeats PCR （ISSR PCR）. Samples including four clones of C. vulgaris and three clones of C. pyrenoidosa were purified by single-clone-choice method. For four C. vulgaris unicellular clones, the total number of the bands scored for 18 primers was 298; and the number of the polymorphic bands was 118, of which 39.6% were polymorphic. The size of PCR products ranged from 200 to 2 500 bp. The total number of bands scored for 18 primers, the number of polymorphic bands and the percentage of three C. pyrenoidosa unicellular clones was 194.83 and 30.8%, respectively. POPGENE analysis show that the average Nei genetic diversity （h^＊） and Shannon index of diversity （I^＊） in the four C. vulgaris unicellular clones was 0.2181 and 0.3208, respectively, which is slightly higher than those of the three C. pyrenoidosa unicellular clones （0.190 3 and 0.274 8）, which agreed with the percentage of polymorphic bands in the mixed samples of the two species. The results suggest that ISSR is a useful method to Chlorella for intra-species genetic analysis.     

Characterization of defensin gene from abalone Haliotis discus hannai and its deduced protein

Defensin is one of preserved ancient host defensive materials formed in biological evolution. As a regulator and effector molecule, it is very important in animals' acquired immune system. This paper reports the defensin gene from the mixed liver and kidney cDNA library of abalone Haliotis discus hannai Ino. Sequence analysis shows that the gene sequence of full-length cDNA encodes 42 mature peptides (including six Cys), molecular weight of 4 323 Da, and pI of 8.02. Amino acid sequence homology analysis shows that the peptides are highly similar (70% in common) to other insects defensin. Because of a typical insect-defensin structural character of mature peptide in the secondary structure, the polypeptide named Haliotis discus defensin (hd-def), a novel of antimicrobial peptides, belongs to insects defensin subfamily. The RT-PCR result of Haliotis discus defensin shows that the gene can be expressed only in the hepatopancreas by Gram-negative and positive bacteria stimulation, which is ascribed to inducible expression. Therefore, it is revealed that the Haliotis discus defensin gene expression was related to the antibacterial infection of Haliotis discus hannai Ino.     

基于Gibbs抽样的贝叶斯方法估计大菱鲆生长和耐高温性状的遗传参数

为了开展大菱鲆耐高温选育工作,对其进行耐高温性状及其相关生长性状的遗传评估是非常必要的。以来源于英国、法国、丹麦和挪威4个国家的不同群体构建大菱鲆选育家系,利用F₁的20个和F₂的22个耐高温选育家系进行耐高温实验,统计耐高温评估指标（UTT）和相应的实验鱼体重（每个家系选取40-50尾实验鱼）。基于Gibbs抽样的贝叶斯方法,采用包含母性效应和不包含母性效应的两种动物模型,对大菱鲆耐高温（UTT）和生长性状的遗传力以及这两个性状间的遗传相关和表型相关进行分析。结果表明,基于不包含母性效应的动物模型估计的体重和耐高温性状的遗传力以及这两个性状之间的表型相关和遗传相关分别为0.239±0.141,0.111±0.080,0.075±0.026和-0.019±0.011。基于包含母性效应的动物模型估计的这4个值分别为0.203±0.115,0.055±0.026,0.047±0.034和-0.024±0.028,体重和耐高温性状的母性效应分别为0.050±0.017和0.013±0.004。母性效应对这两个性状的遗传评估有一定的影响。本文的研究结论为制订合理的大菱鲆耐高温育种规划提供了理论依据。     

斑节对虾3个野生群体遗传多样性的微卫星标记分析

为探究不同地理条件下斑节对虾天然群体的遗传多样性和遗传分化水平, 选用14对简单重复序列(simple sequence repeat, SSR)特异引物对广东湛江、海南三亚、海南琼海的斑节对虾天然群体共计90尾个体进行微卫星标记分析, 每对引物检测出的等位基因数为2~4不等, 平均2.7。3个群体(湛江、三亚、琼海)平均有效等位基因分别为1.9081、1.9715和2.0185, 平均多态信息含量分别为0.3864、0.3926和0.4078, 总的平均期望杂合度(0.4605 )明显高于观测杂合度(0.4046), 表明3个群体遗传多样性水平为中等, 且存在杂合度缺失的现象。种群分化指数和遗传距离分析表明, 在不同群体间已产生了遗传分化, 但是分化较小; 三亚群体和琼海群体之间的亲缘关系最近, 而与湛江群体的亲缘关系最远。分子方差分析表明, 群体间的遗传变异指数为8%, 群体内个体间的遗传变异指数为92%, 基因分化主要发生在群体内, 而不是群体之间。     

中国黄渤海真江蓠(Agarophyton vermiculophyllum)群体遗传多样性研究

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（N_a）为1~28,有效等位基因（N_e）为1.0~9.6。每个群体的平均等位基因（N_a）、平均有效等位基因（N_e）、平均香浓指数（I）、平均观察杂合度（H_o）和平均预期杂合度（H_e）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（F_st=0.398 7）,基因流有限（N_m=0.377 1）,近交系数为正（F_is=0.391 3,F_it=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。     

我国东南沿海坛紫菜遗传多样性研究

利用线粒体COX和叶绿体rbcL基因片段对我国东南沿海坛紫菜(Pyropia haitanensis Chang et Zheng)9个野生群体和2个养殖群体(共125个个体)进行遗传多样性分析。比对分析后得到408 bp的COX基因片断和488 bp的rbcL基因片断。联合分析的基因片断长度为896 bp,其中T、C、A、G的含量分别为34.9%、14.6%、34.2%和16.3%。检测到变异位点128个,其中单碱基变异位点19个,简约信息位点109个。群体的平均核苷酸多样性为0.035 9±0.028 4,单倍型多样性为0.817 0±0.024 0。125个个体共定义了31个单倍型,其中Hap1、Hap10和Hap16是核心单倍型,分别占全部样本的32.8%、12.8%和24.8%。群体遗传距离和地理距离相关性检测显示二者呈线性相关(R²=0.002 2,p=0.735 4),即遗传距离随地理距离的增大而增大,但未形成地理隔离。根据单倍型构建的ML树显示,坛紫菜群体之间没有明显的地理谱系结构,表明各个群体之间存在基因交流。     

五种紫菜同工酶标记的遗传分析

用垂直凝胶电泳来研究采自中国的（条斑紫菜×坛紫菜）杂交种、坛紫菜、条斑紫菜、少精紫菜、半叶紫菜的同工酶多态性。然后分析最小可能位点数和观察同位基因数、遗传差异性和采用平均连接聚类法。选取23种酶带中的六个酶（MDH,ME,LDH,GDH,IDH和G-6-PDH）进行分析。最小可能等位基因位点数显示五种紫菜在ME等位基因位点都只有一个。LDH和GDH等位基因位点半叶紫菜和少精紫菜和另外的三种紫菜不同,而在分析MDH时半叶紫菜比较独特。在IDH位点分析时少精紫菜和坛紫菜和其他三种不同,而条斑紫菜和坛紫菜和其他三种不同在G-6-PDH位点不一致。总的来看,最小可能等位基因位点数分析半叶紫菜是最分离的。遗传多样性结果分析表明当遗传相似度为0．7550时,五种紫菜中的遗传变异研究受到限制。条斑紫菜和坛紫菜的杂交种非常接近少精紫菜。当遗传相似度达到0．8937时,出乎意料的是条斑紫菜和坛紫菜遗传同一。性很低。条斑紫菜4个株系的平均遗传相似度仅为0．7428,差异比较大。在所有紫菜中半叶紫菜是最分化的分支,它与最小可能等位基因位点数分析一致。     

集优性状杂交刺参的健康生态养殖和示范推广

为提高我国刺参的健康生态养殖水平,文章分析韩国红刺参与中国刺参的杂交,通过优势性状的定向选择育种,获得具有集优性状的刺参新品系,兼具韩国红刺参和中国刺参的品质优势,充分发挥韩国红刺参耐高温、夏眠时间短、生长速度快和体壁厚实等优点。养殖实验和研究结果表明：刺参杂交组比刺参对照组的生长速度提高超过25%,成活率提高超过24%;温度和盐度对杂交刺参稚参生长发育的影响显著,稚参阶段的最适温度为20℃～25℃,最适盐度为28～30;刺参杂交组的夏眠时间延迟,内脏未完全消退。根据基础研究结果,应进一步熟化技术,以企业为载体,开展控温室内育苗工作。