云南大叶种茶树种质资源ISSR指纹图谱构建及遗传多样性分析

利用ISSR标记构建了40份大叶种茶树资源的指纹图谱,用3种独立的方法（特殊的标记、特异的谱带类型、不同引物提供的谱带类型组合）可以有效地鉴别大叶种茶树种质资源,证明ISSR标记是鉴定茶树资源的有效方法。15条ISSR引物共扩增出275条谱带,其中274条具有多态性,占99．6％。40份材料间平均遗传相似系数、Nei＇s基因多态性（gene diversity）和Shannon＇s信息指数分别为0．4180、0．3797、0．5586。材料间的遗传多样性较高,说明材料间的遗传距离较远,亲缘关系较远。遗传基础较宽。ISSR聚类分析表明,40份种质资源被聚为3个类群,其中Ⅲ类群又聚为3个亚群。亲缘关系树状图在分子水平上清楚地显示了云南大叶种茶树资源间的亲缘关系,为今后茶树育种和杂交亲本的选择提供了依据。     

叶子花种质资源遗传多样性及亲缘关系的RAPD和ISSR分析

利用RAPD和ISSR标记对48份叶子花种质进行遗传多样性及亲缘关系分析。结果显示:(1)筛选出具有多态性的RAPD引物7条、ISSR引物11条,RAPD引物共扩增97条多态性条带,ISSR引物共扩增140条多态性带,多态性百分率均达100%。(2)根据两种标记的扩增结果,用UPGMA法对48份叶子花种质的聚类分析显示,48份供试材料间具有较丰富的遗传多样性,其品种间遗传相似系数RAPD为0.318 8～0.955 6,ISSR为0.349 5～0.900 0;两种分子标记均能清楚地将48份种质材料区分开来,对种质类群的划分结果基本一致,仅有些许差异。(3)聚类分析结果显示,48份种质可分为两大种系:1)B.glabra种系,其品种大多以其种内来源为主;2)涵盖了B.spectabilis、B.peruviana、B.×buttiana和B.×spectoglabra等4个种的种系,种质构成较为复杂。(4)两种标记聚类结果呈显著相关关系,相关系数为0.752 3。研究表明,对一些形态上无法细分的叶子花种质(类群),RAPD和ISSR分子标记是可靠的鉴别方法。     

中国啤酒大麦品种RAPD标记的遗传多样性分析

采用RAPD技术对中国38个啤酒大麦品种的遗传资源进行了聚类分析。结果表明：从筛选出的28个有多态性的随机引物中,共扩增出153条谱带,其中91条谱带具有多态性,占59．4％。每个引物可扩增出1～8条多态性谱带,平均3．3条。聚类分析表明,在遗传距离GD值0．27水平上38个啤酒大麦品种可聚成两大类,下分5个亚类。品种间遗传距离GD变幅为0．00952～0．37846。RAPD标记揭示出这38个啤酒大麦品种遗传变异较小,遗传基础比较狭窄。     

利用RAPD标记评价小豆种质遗传多样性

本研究利用10个RAPD引物对180份小豆种质的基因组DNA进行扩增,共扩增出44条带,其中35条具有多态性,比例为79．5％,平均每个引物扩增出3．5条多态性带;平均遗传距离为0．274,变异幅度为0．05－0．60,平均遗传多样性指数为0．692;基于RAPD标记,把180份小豆种质聚类划分为4个组群,该组群的划分与小豆的生态地域性似乎不存在明显的相关性。     

紫、红黄肉甘薯种质遗传多样性的ISSR分析

采用ISSR分子标记,分析了21份紫肉、28份红黄肉甘薯种质遗传多样性。结果表明：17对引物共扩增出154条谱带,其中多态性谱带138条,占89.6%,平均每个引物扩增出8.12条多态性谱带,表现出丰富的多态性。聚类分析和主成分分析将49份甘薯种质聚为4大类,类型间遗传差异较大,将红黄薯单独聚为1类,说明紫薯和红黄薯分别具有明显不同的来源和系统演化关系。种质间的遗传相似系数变幅为0.58~0.93,其中,0.61~0.70之间的种质占51.4%,0.71~0.80之间的占44.0%。而邻近地域育种单位或同一育种单位的品种亲缘关系较近。文章对如何在育种中利用这些优异种质进行了讨论。     

采用RAPD技术探讨花椒的遗传多样性及其与环境的关系

采用RAPD分子标记方法分析11个花椒品种的遗传多样性,以及遗传多样性与环境因素的相关性。从60条随机引物中筛选出10条引物,共扩增出67条带,平均每个引物扩增出6．7条,其中56条具有多态性,多态比例为84％。根据品种间的遗传距离构建的聚类分析树状图,11个花椒品种的相似系数在0．08-0．92之间,可分为2个类群,这种分类与花椒的叶的外形分类结果一致。不同地域种植的同一品种材料遗传距离较大,显示花椒的遗传多样性与地域分布有关系。     

乌塌菜种质资源遗传多样性的ISSR分析

利用ISSR技术对48份乌塌菜种质资源进行遗传多样性分析。从60条随机引物中筛选出稳定性强、条带清晰且多态性丰富的9条引物进行PCR扩增,共扩增出103条谱带,平均每个引物扩增出11.4条带,其中多态性带85条,多态性位点百分率为82.68%。不同乌塌菜种质间遗传相似系数变幅为0.59~0.97,说明ISSR标记能够揭示材料间较高的遗传多样性。利用UPGMA聚类分析,ISSR标记能将48份乌塌菜品种完全区分开,48份乌塌菜种质被划分为4个类群,聚类结果与叶片颜色相关,为乌塌菜品种资源的研究利用提供参考。     

不同仙草种源间遗传关系的ISSR分析

采用ISSR分子标记技术对不同种源的20份仙草进行聚类分析。从40条ISSR引物中筛选出18条扩增条带清晰且重复性好的引物,共扩增出114条带,其中多态性条带53条,多态性比率为46.5%。采用NTSYS-pc软件对20份样品进行聚类分析。结果表明,供试20份仙草资源间的遗传相似系数介于0.37～0.96之间,聚类可将其分成3个大类群,其中一类全部为福建、广东和台湾等国内产区的栽培种源,一类为野生种源,另一类包括引自印度尼西亚种源及其与广东朝阳仙草的杂交后代。聚类结果表明仙草种源间的遗传差异与地理分布关系不密切而与形态差异有一定联系。     

罗汉松遗传多样性的SCoT分析

采用SCoT分子标记技术对8份罗汉松种质材料进行遗传多样性研究。结果表明,从80条引物中筛选出10条重复性好、条带清晰的引物进行PCR扩增,共产生136条带,其中多态性带122条(占88.97%),8个罗汉松种质间的遗传相似系数范围在0.39～0.80说明罗汉松的遗传多样性丰富。利用UPGMA进行系统的聚类分析显示,将8份罗汉松材料分为2大类;主成分分析结果与聚类分析结果相一致。可见,利用SCoT分子标记可有效的分析罗汉松种质资源的遗传多样性,为罗汉松种质亲缘关系的鉴别和分类提供理论依据。     

虎杖种质资源的分子标记研究

本文应用RAPD、ISSR和SRAP标记对26份虎杖种质资源遗传多样性进行检测.在22个引物中有17个引物(77.3%)扩增产物具多态性,多态性水平相对较高.22个引物共得到98条扩增DNA片段,其中90.8%具有多态性.每个多态性引物平均可扩增出5.24个多态性片段.聚类分析表明,利用BAPD、ISSR和SRAP技术相结合可将全部供试材料区分开,26份材料在Gs值0.54水平上全部聚为一类,以所有材料间的平均遗传相似遗传系数0.71为阈值,将其分为11类.虎杖种质资源在分子水平上确实存在较大遗传差异,RAPD、ISSR和SRAP标记可作为构建虎杖DNA指纹图谱的有效工具.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.