耐盐绒毛白蜡特异性SCAR分子标记的鉴定

该研究以耐盐型和盐敏感型绒毛白蜡及其F1代为材料,采用混合品系分析法进行RAPD分析。结果显示:在随机选取的150个10碱基随机引物中,仅有引物S20在耐盐基因池和盐敏感基因池间扩增出特异而可重复的592bp的多态性片段,命名为S20-592。获得的RAPD标记S20-592经克隆、测序、重新设计一对特异性引物转化成更稳定的SCAR标记。通过F1代个体验证,耐盐型个体均能扩增出此差异条带而盐敏感型个体中不能扩增出此差异条带,证明该SCAR标记的特异引物可用于耐盐绒毛白蜡物种的快速分子鉴定。     

小麦农家品种红麦(京2747)主效抗条锈病基因的RAPD标记

小麦农家品种红麦(京2747)可抗中国小麦条锈菌多个生理小种。遗传分析表明,该品种对于小麦条锈菌条中19号生理小种的抗性由1对显性基因控制。本研究采用铭贤169×红麦的F2分离群体建立抗、感DNA池,用RAPD方法进行DNA多态性分析。共筛选236个10碱基随机引物,其中引物S1167所扩增出的1条约245 bp的多态性DNA片段只出现在抗病DNA池和红麦中,而不出现在感病DNA池和感病品种铭贤169中。经用201株杂交F2植株对多态性DNA片段S1167245与目的基因的遗传连锁性进行分析,在164株抗病单株中有156株可稳定扩增出该特异DNA片段,而在37株感病单株中则有34株不能扩增出该特异DNA片段,经统计共有11株发生了交换,标记S1167245与目的抗病基因间的遗传距离为6.1cM。本研究得到的RAPD标记S1167245表现稳定、重复性强,可用于小麦抗锈育种中的标记辅助选择,促进红麦的抗条锈基因的利用。     

大豆曲茎性状的遗传分析和RAPD标记研究

曲茎遗传材料NG94-156与遗传背景不同的3个正常茎品种杂交,获得1个F2群体和2个重组自交家系(F7:8)。后代分离分析的结果表明,NG94-156的曲茎性状受两对隐性重叠基因控制。利用4个亲本和1个重组自交家系筛选260个RAPD随机引物,其中有1个引物S-506扩增出的多态性条带有较好的重复性。经过连锁分析,RAPD标记S-5061600与控制曲茎的基因的遗传距离为6.94 cM。     

滨麦抗条锈病基因的染色体定位和分子标记

从滨麦与普通小麦杂交后代中筛选到一条抗条锈病的小滨麦品系93784。以滨麦基因组DNA为探针的荧光原位杂交结果表明,93784是小麦与滨麦的小片段易位系,易位的滨麦染色体片段位于一对小麦染色体的短臂端部,利用该易位系构建了F2分离群体,进行F2单株成株期抗条锈鉴定,抗性分析证明,小滨麦93784中的抗条锈病基因是单基因控制的,位于滨麦染色体的易位片段上,命名为YrLm。进一步采用24对TaqⅠ（T1-T4）/PstⅠd(P1-P6)引物组合对抗感亲本及F2分离群体进行AFLP分析,筛选出一个与抗条锈病基因YrLm连锁的AFLP分子标记,经克隆和测序,该标记片段长度为205bp,定名为P1T3205。     

亚麻抗锈病基因M4的特异分子标记

用520个10碱基随机引物对含有亚麻抗锈病基因M4的近等基因系材料NM4及其轮回亲本Bison进行RAPD分析,其中OPA18引物在NM4材料中稳定地扩增出特异的DNA片段。用Bison与NM4杂交产生的F2分离群体进行的遗传连锁性分析表明,RAPD标记OPA18432与M4基因紧密连锁,二者之间的遗传距离为2.1cM。将OPA18432片段回收,克隆和测序,成功地将其转化为SCAR标记。对不同抗源材料的扩增分析表明,该标记是M4基因的特异标记。目前这一标记已成功地应用于亚麻抗锈病基因M4的分子标记辅助选择育种。     

小麦抗白粉病基因Pm23的RAPD标记

小麦抗白粉病基因Pm23对世界上很多麦区流行的白粉病表现高抗或免疫.本研究以Pm23和Chancellor为抗感亲本,用集群分离分析法对抗性基因Pm23进行了RAPD分析,从320个十碱基随机引物中筛选到一个与Pm23紧密连锁的相引相标记OPE051100. 对F2分离群体进行RAPD分析表明,该标记与Pm23基因之间的连锁距离为10.65±3.25 cM.该标记可以有效用于小麦育种分子标记辅助选择中.     

粘类小麦雄性不育恢复基因的遗传分析及RAPD标记

利用RAPD分子标记对粘类小麦雄性不育系ms（Kots）-90-110的恢复系Rk5451的恢复基因进行了标记定位。选取具有高恢复力的恢复系康本材料Rk5451和Rk5253为父本与ms（Kots）-90-110杂交．F1代再与保持系90-110回交;以90-110／／ms（Kots）-90-110／Rk5451的BC1F1代分离群体为研究对象．利用分离群体分组分析法（Bulked Segregant Analysis．BSA）．以350个随机引物对Rk5451的主效恢复基因进行RAPD分析．筛选到27个可在亲本间扩增出多态性的引物．其中引物S120经多次重复能在亲本间及不育和可育池间扩增出稳定的多态性片段S120-1745。     

与苹果Co基因紧密连锁的RAPD标记的筛选及其SCAR标记转换

以短枝富士(Spur Fuji)X舞姿(Telamon)的105株F1群体为试材,利用RAPD技术,结合集群分类分析法(BSA)进行了苹果柱型基因(Co)分子标记的研究。通过对300条随机引物的筛选,获得一个与Co基因紧密连锁的RAPD标记S1142682,连锁距离为2．86cM。对该标记片段进行序列测定,然后根据序列特点设计了4条特异引物(其中正向引物与反向引物各两条)。PCR结果显示,这4条引物的4种组合都可以扩增出柱型性状的特征带。选其中之一进行群体上的分析,结果表明该SCAR标记特征带与柱型性状的共分离行为与原RAPD标记表现一致。可见,此组合的引物可以作为该SCAR标记的特异引物。通过对S1142682标记片段序列分析发现,在 45～ 251区域含有一个可编码68个氨基酸残基的ORF。     

小麦耐盐种质的筛选鉴定和耐盐基因的标记

通过对 40 0份材料的芽期、苗期鉴定 ,筛选出 11份耐盐性较强的普通小麦 (TriticumaestivumL .)、小麦和黑麦 (SecalecerealeL .)、小麦和延安赖草 (Leymuschinensis (Trin .)Tzvel.)杂交后代材料 ,其中耐盐性突出的材料有 :普通小麦品种“红蚂蚱”、“科遗 2 6”、“希望”(Hope) ;小麦与黑麦杂交后代材料 98_46、98_113、98_131;小麦与延安赖草杂交后代材料 98_16 0、98_16 1、98_16 3。耐盐性表现最突出的材料是 98_113和 98_16 0。细胞学鉴定和原位杂交及醇溶蛋白酸性聚丙烯酰胺凝胶电泳 (A_PAGE)分析和低分子量谷蛋白SDS_PAGE分析 ,证明 98_113是稳定的小麦 黑麦二体附加系 ,但具体附加的是黑麦的哪条染色体还不清楚 ;98_131是小麦 黑麦 1B/ 1R易位系。结合其他 1B/ 1R材料的耐盐表现 ,提出了黑麦 1R染色体短臂上存在耐盐基因的可能性。对 (98_16 0×BanacakaMska)F2 代分离群体苗期抗盐鉴定分析 ,表明在这一杂交组合中的耐盐性状可能由一个主效基因控制。应用SSR标记技术 ,筛选到了与 98_16 0耐盐性状连锁的SSR标记WMS6 7和WMS2 13,它们与耐盐基因的遗传距离分别为 13.9cM (centMorgan)和 31.0cM。结合小麦SSR图谱分析 ,将该主效抗性基因定位在 5BL上。     

家蚕耐氟基因RAPD分子标记的筛选及其克隆

为获得家蚕耐氟基因的分子标记,以家蚕耐氟品种T6和高敏感品种733新为材料,并构建了其近等基因,采用300个随机引物进行RAPD扩增,获得了与家蚕耐氟性有关的一个分子标记,此标记由引物S250扩增得到,并在F2代分离个体中得到验证,证明了此分子标记的可靠性,进而将此标记克隆进T载体pmd-18中,完成测序,分析发现此序列是未有报道的新序列。     

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.