优势基因

1Niche construction can lead to stable coexistence of diverse genotypes in spatially structured population, which supports a stable polymorphism even without heterozygote superiority.(2)With habitat deterioration, niche construction accelerates the formation of steady polymorphism and hence impedes the harmful influences of environment on the population, which might embody a life-history strategy of organism under the unfavorable environment.(3)Niche construction results in the coexistence with alternative polymorphism through genotype-environment feedback and limited gene flow.(4)The niche-constructing organism is an active force to alter its environment and hence the direction of natural selection in order to better survival.(5)Spatial dynamics and distribution pattern of metapopulation are profoundly influenced by time-lagged niche construction.(6)Metapopulation size can reach a fixed level in the recency effect and equal weighting of time lag but is statistical stability in primacy effect, which implies the primacy effect is most remarkable.(7)The increment in the relative weightingof each generation\' niche construction and the length of time lag are significant factors for system destabilization.(8)Moderate capacity of positive niche construction benefits the metapopulation persistence.(9)The narrowing of niche breadth can decrease the metapopulation size and thereby increase the extinction risk.(10)The coupled function of time lag and niche construction make the system oscillation and generate the spiral wave, spiral-broken and circular wave in heterogeneous habitat.The spatial distributions of metapopulation and resource content are complementary due to a phase lag of their both frequencies.(12)Metapopulation persistence with niche construction depends not only on the balance between colonization and extinction, but also on the balance between the ability of niche construction and natural dissipation of habitat.(13)Metapopula-tion can survive under certain condition when the percent of suitable patches in habitat is lower than the ration of extinction to colonization.(14)Two thresholds exist in the process of transition of habitat quality dynamics from unsuitable to suitable, which include the intensity of niche construction and the initial condition of system.(15)Metapopulation size is positive correlated with the ability of positive niche construction, which means that organism or population who has strongly positive influences on their environment plays an important role to maintain the available habitat.

通过上述几个方面的研究，主要得出以下15条结论：(1)生态位构建可使空间结构种群，甚至是在没有杂合子优势的条件下，形成多种可能的稳定基因型分布模式；(2)随着环境的破坏与恶化，种群的生态位构建作用加速其较早形成稳定多态以阻碍环境对种群的不利影响，解释了有机体在不利环境下的一种生活史对策；(3)生态位构建作用通过基因型—环境反馈机制及有限的基因交流导致基因型多态的稳定共存；(4)有机体的生态位构建作用是一种积极的动力改变环境进而改变其自然选择的方向；(5)生态位构建的时滞作用对集合种群动态和空间分布产生深刻影响；(6)集合种群大小在时滞的崭新效应和等权重效应下达到一固定值，而在首位效应下达到统计稳定，表明首位效应的影响最显著；(7)首位效应下生态位构建相对权重的增量和时滞的长度是影响系统不稳定性动态的关键因素；(8)适中的生态位构建强度有利于集合种群的续存；(9)生态位宽度变窄会减少集合种群的数量从而增加其灭绝风险；(10)时滞和生态位构建的双重作用使系统产生周期振荡，并在异质性环境中产生稳定的螺旋波，破碎的螺旋波和环形波三种分布模式；(11)集合种群与资源含量的空间分布因为相滞而互补；(12)具有生态位构建的集合种群续存不仅取决于侵占率与灭绝率之间的平衡，而且依赖于生态位构建能力同其生境的自然消耗速率之间的妥协；(13)当生境中适合侵占的斑块比例小于其侵占率与灭绝率之比时，生态位构建作用促使集合种群在一定条件下续存：(14)生境斑块的状态从不适合到适合转变过程中存在生态位构建强度和系统初始条件这两个阈值；(15)集合种群的大小同正生态位构建能力正相关，意味着对环境具有较强正作用的有机体对维持有效生境起积极作用。

A clone from each genotype was randomly selected as representative for sequencing. The obtained 16S rDNA gene sequences had a similarity of 87%-100% with those in the GenBank (www. ncbi. nlm. nih. gov), and more than half of them had a similarity lower than 97%, being of new species. Based on phylogenetic analysis, the bacteria in the two soils were classified into 10 groups, with 5 groups in common. The dominant bacterial groups in the two soils differed obviously. In primeval forest soil, the dominant group was Proteobacteria, which had 39 genotypes, occupying 58.0% of all the clones; while in the soil of degraded ecosystem the dominant groups were Acidobacteria and Proteobacteria, which had 19 and 15 genotypes occupying 32.5% and 30.5% of all the clones, respectively. In the soil of degraded ecosystem, Proteobacteria group decreased while Acidobacteria group increased markedly, compared with those in primeval forest soil.

从每种基因型中随机选择一个克隆子作为代表进行测序分析，所有序列与GenBank数据库中序列的同源性为87%~100%，且两样地中均有超过一半的基因型序列与数据库中已知序列同源性低于97%，属于分类在"种"地位上的新发现细菌；通过系统发育研究将两样地的细菌分为10大类群，两样地共同拥有5大类群，但两样地的细菌优势类群明显不同，原生土壤为Proteobacteria，含39种基因型，占总克隆子数的58.0%，退化生态系统土壤为Acidobacteria和Proteobacteria，分别含19种和15种基因型，占总克隆子数的32.5%和30.5%；与原生土壤细菌类群相比，退化生态系统土壤Proteobacteria类群明显减少，Acidobacteria类群明显增加。

Sex-linkage model reveals that hybrid vigor rate is a complex function related withdominance of gene effects of hybrid,additivity and dominance of the parent genes,and ef-fects of sex-linked genes.Owing to interaction of genes and environment,hybrid vigor ratevaries with seasons.

性连锁模型揭示，杂种优势率是一个与杂交种的显性效应、亲本的加性效应、显性效应、性连锁效应等基因效应有关的复杂函数，由于基因与环境的互作，造成杂种优势率在不同季节表现不一致。

After thecomplete genome extraction of the strain was performed, the genomic DNA was partiallydigested by restriction enzyme Sau3AⅠ, the DNA fragments from 1 to 5Kb was clonedinto prokaryote expression vector pET-28a-c, and transformed host bacteria. The resultsshowed that we succeeded in constructing the gene expression library of haemophilusparasuis serovar 5, which is fundamental for the study of advanced gene screening. Inaddition, primer design was performed based on haemophilus influenzae in this study. In addition, PCR was performed by using genomic DNA of haemophilus parasuisserovar 5 as the template. The results demonstrated that we obtained two neo-gene:23SrRNA gene(conserved gene belonging to the large-subunit of ribosome) and adenylatecyclase gene(encodes adenylate cyclase and participates in converting adenyl nucleosidetriphosphate to cyclic adenosine3",5"-monophosphate). Furthermore, the phylogeneticanalyses between the species was performed, and neighbor-joining tree was constructedbased on comparison of 23S rRNA gene sequences, so it was illuminated betweenHaemophilus parasuis and other species in molecular evolution relationship.

选择我国流行优势菌株副猪嗜血杆菌血清5型地方株为研究对象，提取细菌基因组DNA，用限制性内切酶Sau3AⅠ对基因组DNA进行部分酶切，回收大小为1～5Kb的DNA片段，将其连接入原核表达载体pET-28a-c，最后转化宿主菌，结果成功地构建了基因表达文库，为后续的基因筛选工作奠定基础；另外，本研究选择嗜血杆菌属的流感嗜血杆菌为参考对象进行引物的设计，以副猪嗜血杆菌血清5型地方菌株的基因组DNA为模板，进行PCR扩增反应，结果表明成功地获得两个新基因：23S rRNA基因(存在于核糖体大亚基中的保守性基因)和腺苷酸环化酶基因(负责将腺嘌呤核苷三磷酸转变为环腺苷酸)，并进一步做了不同物种之间的分子系统发育分析，构建了基于23S rRNA基因的邻接法系统发育树，阐明了副猪嗜血杆菌与其它菌种的分子进化关系。

On the basis of DDRT-PCR technique we found that:Total of 331 differential displayed cDNA bands from 1161 were displayed in the 4x4 diallel cross combinations with 30 pairs of primers, which shows the differences of gene expression between hybrids and their parental lines were very obvious in quantity and quality.

采用mRNA差异显示技术和荧光定量反转录PCR技术，从随机mRNA差异显示和候选功能基因mRNA表达定量分析两个方面，研究了32周龄杂种鸡及其亲本纯种的基因差异表达及其与繁殖性状杂种优势的关系，探讨了鸡繁殖性状杂种优势形成的因素及其分子遗传机理。

The main results are as followings:1 Molecular mechanism analysis of the rice heterosis by functional genomics method.1.1 In five gene chips, 845 genes that are discrepantly expressed were found.

研究结果如下： 1 运用基因芯片对水稻杂种优势分子机理的解析： 1.1 5张基因芯片检测出845个差异表达基因，涉及多种植物功能，表明杂种优势的表现与多种代谢途径相关。

The experiment obtains clone pig HUMMLC2B gene (GenBank logs onto date: DQ533994), use PCR-RFLP technology, analysed HUMMLC2B gene the 1st embedded child medium Msp Ⅰ is enzymatic cut much condition (T613C) is in distributinging; analysed the much condition sex in 7 breed pig 5 many condition sex and 36 long white pigs, groups 104 pigs and grow to be mixed in vain 5, the result makes clear, the scale that waits for a gene and B to wait for a gene frequency except the A in long white pig in detected swinery is 1 ∶ 2 outside, of the others all take absolutely advantage for a gene such as B, and a gene such as A is pure close individual detect in long white pig only.

实验获得克隆猪HUMMLC2B基因(GenBank登录号：DQ533994)，并采用PCR-RFLP技术，分析了HUMMLC2B基因第1内含子中的MspⅠ酶切多态(T613C)在7个品种猪中的多态性分布；分析了多态性和36头长白猪、5个群体104头猪以及长白和5个群体之和的140头猪胴体性状和肉质性状间的相关，结果表明，在检测的猪群中除长白猪中A等位基因和B等位基因频率的比例为1∶2外，其余的均为B等位基因占绝对优势，且A等位基因纯合个体只在长白猪中检测到。

Under the condition [0mmol/L,raise in vermiculite] of phosphorus stress, variation in root morphology and biomass among different soybean genotypes at seedling stage were studied, the result shows: At two-leaf age, higher P-efficiency genotypes(K1 and K2) don't develop their potential advantages; at four-leaf age, some characteristics of K1 and K2, such as lateral root number, lateral root length, root absorbent area and dry weight of shoot are all less reduced than those of intermediate P-efficiency genotypes(Z1 and Z2) and of lower P-efficiency genotypes(M1 and M2), and dry weight of root and R/S of higher P-efficiency genotypes are more increased than those of the others.

在磷胁迫[0mmol/L，砂培]条件下，对不同基因型大豆苗期在根系形态、生物量等方面的差异进行了研究，结果表明：磷高效基因型在两叶期并未发挥出其基因型潜力的优势；四叶期，磷高效基因型的侧根数、侧根长、根系吸收面积、茎叶干重等性状的受抑制程度均显著低于磷中、低效基因型，而地下干重、根冠比却受到了较中、低效基因型更强的诱导作用。

In order to understand the molecular basis of heterosis, modified differential display of mRNA was used to characterize the difference in gene expression between cross-fertilized and self-fertilized kernels, reciprocal cross-fertilized kernels and their parents during the early stages of seed development by using 3 wheat hybrids with different level of heterosis.

本研究旨在利用mRNA差异显示技术探讨小麦杂交种子和自交种子以及正反杂交种子与其双亲在种子发育前期的基因表达差异，同时对杂种优势利用的模式作物玉米的杂交种子和自交种子的基因表达差异也进行了研究，并对典型的差异表达片段进行了克隆测序，为揭示杂种优势形成的分子机理积累了更多的资料，取得的主要结果如下

By using gene-family-specific primers, we found MADS-box, Ser/Thr protein kinase showed significantly differential expression patterns between reciprocal cross-fertilized kernels and their parents, indicating that MADS-box and ser/thr protein kinase may also play important roles in wheat heterosis.

利用家族特异性引物的展示结果表明，MADS-box家族基因在小麦杂交当代种子与亲本之间存在明显的基因表达差异，且强优势的杂交组合与弱优势组合之间表现差异的cDNA比例差异显著；Ser/Thr蛋白激酶的差异相对较小，表明MADS-box和Ser/Thr蛋白激酶与小麦杂种优势形成有重要关系。

Lugalbanda was a god and shepherd king of Uruk where he was worshipped for over a thousand years.

Lugalbanda 是神和被崇拜了一千年多 Uruk古埃及喜克索王朝国王。

I am coming just now,' and went on perfuming himself with Hunut, then he came and sat.

我来只是现在，'歼灭战perfuming自己与胡努特，那麼，他来到和SAT 。