水稻品种多样性田间稻瘟病菌群体遗传结构分析

利用稻瘟病菌的一段倒位重复序列Pot2设计的一对引物,采用rep—PCR分子指纹技术对来自石屏县净种杂交稻田块、净种糯稻田块以及间种杂交稻糯稻田间的251个稻瘟病单孢分离菌株进行扩增．结果表明,所有供试菌株均分别扩增到9—17条DNA带,大小从400bp到23kb左右,但大多数带主要集中在5—10kb之间．所有菌株共扩增出的DNA指纹带中,约65％的为多态性DNA带,35％的为共同扩增带．将供试菌株扩增带诺进行聚类分析,比较间裁与净载田间病菌群体遗传结构的组成差异结果表明,在不同遗传相似水平,菌株遗传宗群复杂度与栽培方式有一定相关性。间栽田间病菌遗传宗群较净栽田问复杂,为3—5个,且优势宗群群不明显;而在净栽糯稻或净栽杂交稻田间遗传宗群较为简单,只有1—3个,且优势宗群明显．本试验结果证明水稻品种多样性有利于稻瘟病菌稳定化选择。     

江苏省稻瘟病菌的毒性多样性及水稻品种的抗病性

在13个已知日本抗病基因品种上检测1997－1999年采集自江苏省吴江,赣榆,通州,高邮和宜兴等5个代表地区的324个稻瘟病菌株的毒性,结果可将上述菌株划分为90种毒性类型,表明江苏省稻瘟病菌存在着丰富的毒性多样性,毒性类型组成在地区间存在较大的差异,并且随着时间的推移,稻瘟病菌毒性类型组成有差异加大的趋势,在已知抗病基因品种上测定江苏省稻瘟病菌的毒力,结果显示：Pi-k^3,Pi-ta,Pi-ta^2和Pi-sh等抗病基因对江苏省的稻瘟病菌的抗谱很窄,而Pi-i,Pi-z,Pi-z^t和Pi-b等抗病基因的抗谱比较宽,可作为抗源加以利用,用6个代表性毒性类型菌株接种江苏省80筱水稻主载品种和新育成品种,品种抗性分析表明,上述水稻品种中的籼稻和杂交稻对江苏省稻瘟病菌具有较高的抗性,而粳稻品种的抗性较差,上述研究结果为利用水稻品种抗性多样性控制稻瘟病提供了依据。     

水稻品种过氧化物酶活性和木质素含量与抗稻瘟病菌的关系(简报)

8个水稻品种的幼苗接种稻瘟病菌后,第3d抗病品种比感病品种过氧化物酶活性增加得快,5～7d后则相反。未接菌的抗病品种比感病品种含有较多木质素。接菌后第7d感病品种较抗病品种诱导了更多木质素。表明稻瘟病菌侵染早期,过氧化物酶活性的增加与抗病性有一定相关性,出现病斑症状后相关性则不明显。     

镉低积累水稻资源的镉积累稳定性及遗传相似性分析

以9311为高镉对照,湘晚籼12号为相邻低镉对照,2014-2017年经田间鉴定筛选出的15份镉低积累水稻资源为参试材料,鉴定精米的相对降镉率并筛选出年度间相对降镉率差异不显著的资源;采用45对SSR引物检测15份资源的遗传多样性,提出遗传距离大且相对降镉率高的育种可用资源.2018年试验结果表明,15份低镉水稻资源的...     

不同亲和性水稻材料的同工酶遗传多样性分析

采用同工酶标记对亲籼、亲粳、广亲和及非亲和4组不同亲和性水稻材料的遗传变化和遗传结构进行分析。10种同工酶在95个材料中共检测到34个同工酶位点和55个等位基因,其中多态位点15个,多态位点百分率为44.12%。各组的平均期望杂合度在0.354到0.456之间,在物种水平上为0.454。AMOVA分析表明,80.21%的遗传变化分布于组内,19.79%的遗传变化分布于组间。各组间的遗传距离变化范围从0.1129到0.3673,基因流变化范围从1.0242到2.5451。根据遗传距离进行的UPGMA聚类分析,将广亲和与亲粳水稻聚为一类,亲籼与非亲和水稻聚为一类。     

黑龙江省近年审定水稻品种基于SSR标记的遗传多样性分析

为评估黑龙江省水稻品种的遗传基础,利用24个用于水稻DNA指纹图谱构建的SSR标记以及其他均匀分布于水稻12条染色体的38个SSR标记,对黑龙江省近年审定的73个水稻常规稻品种进行遗传多样性分析。结果表明,在62个SSR标记位点中,共检测到142个等位基因,平均每个标记2.3个,多态性比率平均为71.0%,多态性频率变幅为0~0.775,平均值为0.246。供试品种间两两遗传相似系数的平均值为0.759,变幅为0.622~0.966,且96.4%的品种间遗传相似系数在0.66~0.86之间,表明供试的73个品种亲缘关系较近。通过SSR标记基因型聚类分析将这些品种划分为6个类群,与系谱分析趋势一致,类群间的差异主要表现在生育期和米质方面。综上所述,黑龙江省近年审定的水稻品种遗传基础狭窄,在育种中需要导入新的种质资源,加强种质资源创新,以期丰富水稻品种的遗传多样性,进一步提高水稻产量和抗性。     

中国水稻地方品种与选育品种遗传多样性的比较分析

利用98对SSR标记对202份中国水稻地方品种和选育品种的遗传多样性进行比较分析.结果显示供试品种具有较丰富的遗传多样性,共检测到等位基因1350个,每个位点的等位基因数(Na)变化范围为3～ 39,平均14个;Nei基因多样性指数变化范围(He)为0.125 ～0.955,平均0.733;多态信息量(PIC)变化范围为0.122 ～0.953,平均0.680;稀有等位基因数(Nr)913个;等位基因丰度(Rs)8.33.栽培稻地方品种和选育品种遗传多样性差异明显,地方品种等位基因数、Nei基因多样性指数、多态信息量、稀有等位基因数和等位基因丰度(Na=1219,He=0.747,PIC=0.710,Nr=756,Rs =8.50)均高于选育品种(Na =919,He =0.704,PIC =0.650,Nr=529,Rs =7.01).各染色体组水平的遗传多样性分析表明,选育品种仅在1号染色体上的遗传多样性高于地方品种,进一步分析显示选育品种的遗传改良在基因组水平上具有区间特异性.     

云南水稻地方品种月亮谷的群体多样性分析

月亮谷是云南元阳梯田种植历史悠久、种植面积最大的优良水稻地方品种之一,当地少数民族具有引种或换种的稻作习惯。为揭示这种稻作习惯对月亮谷群体遗传多样性的影响,本研究对该品种群体内和群体间进行了遗传多样性的比较和分析,目的是为更好地了解月亮谷的群体遗传结构,为持久利用地方品种提供理论依据。首先采用分层随机取样的策略从元阳梯田不同海拔获得24个原位栽培群体,采用形态指数分类法和抗病性测定对24个群体共720个单株样品的月亮谷进行形态学分类和稻瘟病抗性鉴定,并分析了这些单株材料在48个SSR位点的遗传多样性。研究结果表明,形态上月亮谷属于栽培稻的籼稻类型,其群体对稻瘟病具中抗水平,但无论是在群体内还是群体间,均普遍表现出明显差异,说明不同来源的月亮谷存在抗病功能表型上的变异;遗传多样性分析显示,48对SSR引物共检测出91个多态位点,多态性位点百分率为77.08%,Nei多样性指数平均值为0.064,变幅为0~0.4302。24个群体之间的遗传相似系数在0.9753~0.9866之间,群体内个体之间的遗传相似系数在0.86~1.00之间;AMOVA分析显示,以地理村寨作为自然居群单位,居群间的变异为3.36%,居群内群体间的变异为33.15%,居群内的变异为63.49%;聚类分析显示,村寨群体间的遗传多样性与村寨间的地理空间距离有一定相关性。     

宁夏不同年代水稻品种的遗传多样性比较

对宁夏不同阶段主栽水稻品种(系)的主要农艺性状比较表明,第1阶段(1950-1962年)宁夏地方品种与第2阶段(1978-1989年)、第3阶段(1990-1999年)、第4阶段(2000-2005年)、第5阶段(2006-2012年)、第6阶段(2010-2013年)育成品种(系)的农艺性状差异显著,说明通过育种手段宁夏水稻品种的主要农艺性状得到了改良;从第2阶段到第6阶段的变化趋势为生育天数变长,有效穗数减少,穗长、穗粒数、单株粒重、单穗粒重、产量等增加,说明产量性状的育种改良从穗数型向穗粒兼顾型或穗重型发展。利用48对SSR引物对76份宁夏不同年代水稻品种(系)进行遗传多样性分析表明,共检测出290个等位基因,每个位点等位基因变幅为3~15个,平均6.04个;稀有等位基因有109个,占等位基因总数的37.59%;多态信息含量(PIC)变异范围为0.1423~0.8783,平均为0.5512;Nei’s基因多样性指数(He)的变幅为0.1492~0.8945,平均为0.6032。RM333、RM297、RM249、RM501和RM206引物表现为较高的等位基因数和稀有等位基因数,认为较适合应用于宁夏水稻品种的遗传多样性检测。分子方差分析(AMOVA)结果表明,6个不同阶段间遗传变异占总体变异的19.27%,各阶段内品种间的遗传变异占总体变异的80.73%。参试水稻UPGMA聚类分析表明,在遗传相似系数(GS)为0.805处可将其划分为5大类群,12个地方品种都被聚为第Ⅰ类群,具有外来引进血缘的8个常规粳稻品种被聚为第Ⅱ类群,5个优质常规粳稻被聚为第Ⅲ类群,第Ⅴ类群包括2个大穗高产品种,49个宁夏常规粳稻选育品种被聚为第Ⅳ类,说明大多数宁夏水稻品种的亲缘关系较近。6个不同阶段品种聚类分析,第1阶段(地方品种)独聚一类,第2、第3、第4阶段与第5、第6阶段育成品种亲缘关系相对较远;表明不同年代宁夏水稻遗传多样性有较大差异,2005年后宁夏水稻品种的遗传多样性趋于变小。宁夏水稻育种中应加强国内外种质资源的引进和利用,深入挖掘宁夏稻区地方品种和杂草稻资源的有利基因,拓宽宁夏水稻品种的遗传基础,以促进宁夏水稻育种的快速发展。     

A Pid3 allele from rice cultivar Gumei2 confers resistance to Magnaporthe oryzae

Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases. Using map-based strategy and in silico approach we isolated a new rice (Oryza sativa L.) blast resistance allele of Pid3, designated Pi25, from a stable blast resistance cultivar Gumei2. Overexpression analysis and complementation test showed that Pi25 conferred blast resistance to M. oryzae isolate js001-20. Sequence analysis showed that Pi25 was an intronless gene of 2772 nucleotides with single nucleotide substitution in comparison to Pid3 at the nucleotide position 459 and predicatively encoded a typical coiled coil-nucleotide binding site-leucine rich repeat (CC--NBS--LRR) protein of 924 amino acid residuals with 100% identity to Pid3 putative protein. The susceptible allele pi25 in Nipponbare contained a nonsense mutation at the nucleotide position 2209 resulting in a truncated protein with 736 amino acid residuals. In addition, 14 nucleotide substitutions resulting in 10 amino acid substitutions were identified between Pi25 and pi25 upstream the premature stop codon in the susceptible allele. Although the mechanism of Pi25/Pid3-mediated resistance needs to be further investigated, the isolation of the allele would facilitate the utilization of Pi25/Pid3 in rice blast resistance breeding program via transgenic approach and marker assisted selection.     

重复力估计值的概率分布及其假设检验和区间估计

本文用概率论的方法导出了重复力估计值的概率分布密度函数,并对重复力的假设检验和区间估计也进行了讨论。     

有限群体中基因频率概率分布的模拟实验

本文采用计算机模拟的方法,对有限群体中基因频率的概率分布进行了研究。The probability distribution of gene frequency was studied by simulative method in finite population.     

Variable selection and pattern recognition with gene expression data generated by the microarray technology

Lack of adequate statistical methods for the analysis of microarray data remains the most critical deterrent to uncovering the true potential of these promising techniques in basic and translational biological studies. The popular practice of drawing important biological conclusions from just one replicate (slide) should be discouraged. In this paper, we discuss some modern trends in statistical analysis of microarray data with a special focus on statistical classification (pattern recognition) and variable selection. In addressing these issues we consider the utility of some distances between random vectors and their nonparametric estimates obtained from gene expression data. Performance of the proposed distances is tested by computer simulations and analysis of gene expression data on two different types of human leukemia. In experimental settings, the error rate is estimated by cross-validation, while a control sample is generated in computer simulation experiments aimed at testing the proposed gene selection procedures and associated classification rules.     

负二项分布概率的最大值点

本文给出了负二项分布概率取的最大值的点,并给出了证明及例子.     

The complex structure of hunter-gatherer social networks

In nature, many different types of complex system form hierarchical, self-similar or fractal-like structures that have evolved to maximize internal efficiency. In this paper, we ask whether hunter-gatherer societies show similar structural properties. We use fractal network theory to analyse the statistical structure of 1189 social groups in 339 hunter-gatherer societies from a published compilation of ethnographies. We show that population structure is indeed self-similar or fractal-like with the number of individuals or groups belonging to each successively higher level of organization exhibiting a constant ratio close to 4. Further, despite the wide ecological, cultural and historical diversity of hunter-gatherer societies, this remarkable self-similarity holds both within and across cultures and continents. We show that the branching ratio is related to density-dependent reproduction in complex environments and hypothesize that the general pattern of hierarchical organization reflects the self-similar properties of the networks and the underlying cohesive and disruptive forces that govern the flow of material resources, genes and non-genetic information within and between social groups. Our results offer insight into the energetics of human sociality and suggest that human social networks self-organize in response to similar optimization principles found behind the formation of many complex systems in nature.     

系统发育网络的构建与应用

系统发育网络目前主要应用于表达种上复杂的网状进化关系、种内个体及群体之间的关系以及相互矛盾数据集的系统发育分析结果3个方面。本文在综述网状进化现象的基础上,介绍了目前用于构建系统发育网络的几种常用方法,包括T-Rex软件包的网状图法,Tcs软件中的统计简约法,Splitstrees4的中间网法、二分裂法和邻接网法。     

On the estimation of mean parameter with random number of observations on each unit

In this paper an attempt has been made to estimate the population parameter, mean, of a normal population when the number of observations taken on each unit is a random variable and is supposed to follow a Truncated POISSON Distribution.     

A proposal for using the ensemble approach to understand genetic regulatory networks

Understanding the genetic regulatory network comprising genes, RNA, proteins and the network connections and dynamical control rules among them, is a major task of contemporary systems biology. I focus here on the use of the ensemble approach to find one or more well-defined ensembles of model networks whose statistical features match those of real cells and organisms. Such ensembles should help explain and predict features of real cells and organisms. More precisely, an ensemble of model networks is defined by constraints on the "wiring diagram" of regulatory interactions, and the "rules" governing the dynamical behavior of regulated components of the network. The ensemble consists of all networks consistent with those constraints. Here I discuss ensembles of random Boolean networks, scale free Boolean networks, "medusa" Boolean networks, continuous variable networks, and others. For each ensemble, M statistical features, such as the size distribution of avalanches in gene activity changes unleashed by transiently altering the activity of a single gene, the distribution in distances between gene activities on different cell types, and others, are measured. This creates an M-dimensional space, where each ensemble corresponds to a cluster of points or distributions. Using current and future experimental techniques, such as gene arrays, these M properties are to be measured for real cells and organisms, again yielding a cluster of points or distributions in the M-dimensional space. The procedure then finds ensembles close to those of real cells and organisms, and hill climbs to attempt to match the observed M features. Thus obtains one or more ensembles that should predict and explain many features of the regulatory networks in cells and organisms.     

A proposal to evaluate the fibers’ break probability in ligaments and tendons

Understanding the yield and failure mechanisms of ligaments and tendons is important to have a deeper knowledge of their structure and function. Evaluating what are the limits of the human body is also important to prevent injuries in workers, in athletes and the elderly. The tissue yield mechanism was analyzed by modifying and extending a probabilistic model of collagen bundles. Since not usable experimental data are available in the literature, the model and the method were tested using Monte Carlo simulations. The simulations showed many crucial aspects of the model and gave some indications about possible future real validation experiments. The analysis of the correlation between the simulated data, the model () and the Signal-to-Noise-Ratio (SNR) highlighted the most important parameters that affect effectiveness of the described method: number of fibers, elongation step, noise. This analysis also showed that the numerical differentiation algorithms of the data have a key role on the accuracy of the yield assessment. However, the results also showed that the method is able to correctly estimate the elongation break distribution of the fibers of ligaments and tendons.