新疆猪毛菜属植物染色体数及核型分析

以5种新疆猪毛菜属植物为材料,常规压片法制片后观察记录染色体数,并进行核型分析。实验结果表明:钠猪毛菜体细胞染色体数2n=18;浆果猪毛菜2n=2x=18=12m 6sm,属2A核型;木本猪毛菜2n=2x=18=16m 2sm,属2A核型;东方猪毛菜2n=4x=36=26m 10sm,属2B核型;长刺猪毛菜2n=4x=36=24m 4sm 8st,属2B核型。猪毛菜属植物的染色体基数为9,东方猪毛菜、长刺猪毛菜为四倍体,其它3种均为二倍体。与Бочанцев基于形态学特征建立的分组系统及各组的演化地位相比,东方猪毛菜属于原始的硬叶猪毛菜组,而本研究表明该种在核型上相对较为进化;其余3种核型地位与所属组的演化地位相符。     

In vitro induction of tetraploid in pomegranate (Punica granatum)

Tetraploid plants were obtained in pomegranate (Punica granatum L. var. `Nana') by colchicine treatment of shoots propagated in vitro. Shoots cultured on MS medium supplemented with 10 mg l^–1 colchicine, 1.0 mg l^–1 BA and 0.1 mg l^–1 NAA for 30 days produced tetraploids at a high frequency of 20%. No tetraploids were detected by treating the shoots in 5000 mg l^–1 colchicine for 114 h. Shoots treated by 5000 mg l^–1 colchicine for 96 h produced three morphological mutants with narrow leaves, which were later confirmed as mixoploids that separated into diploids and tetraploids after further subculture. In vitro tetraploid plants had shorter roots, wider and shorter leaves than the diploid ones. Tetraploid pomegranate plants grew and flowered normally in pots, but possessed flowers with increased diameter and decreased length compared to diploids. The number of pollen grains per anther was higher in tetraploids, but the viability of pollen decreased significantly.     

国产蕺菜的染色体数目变异及核穿壁现象

蕺菜 Houttuynia cordata Thunb.属三白草科蕺菜属,俗称鱼腥草、侧耳根等,主要分 布于 亚洲东部和东南部,我国以长江流域及其以南各省区常见。蕺菜药蔬兼用,为极具开发前景 的植物资源。部分学者曾对蕺菜染色体数目进行过报道,但报道的染色体数目不尽一致（梁汉兴,1991,1995; Hsu,1968; Nilsamranchit et al, 1999）,并且对此 现象未作较为详细而深入的解释。本文对国内部分省区收集的蕺菜种质资源进行染色体数目分析,旨在从细胞学角度探讨蕺菜的遗传多样性,为     

Effect of CO2 on short-term human lymphocyte culture in vitro

Summary There was no significant difference in the mitotic indices of the cultures maintained at different CO₂ concentrations, i.e. 0%, 5% and 10%. However, considerable variation was recorded among different individuals. Supported by National Cancer Institute Contract No. 1 CP 43251.     

Construction and characterization of BAC libraries for three fish species; rainbow trout, carp and tilapia

Bacterial artificial chromosome (BAC) libraries are important tools for genomic research. We have constructed seven genomic BAC libraries from three fish species, rainbow trout (Oncorhynchus mykiss), carp (Cyprinus carpio) and tilapia (Oreochromis niloticus). The two rainbow trout BAC libraries have average insert sizes of 58 and 110 kb. The average size of inserts in the carp BAC library is 160 kb. The average insert sizes of the four tilapia BAC libraries are 65, 105, 145 and 194 kb, respectively. These libraries represent good coverage of each genome (2-64 x coverage). The libraries can be screened by conventional colony hybridization and provide a starting point for the construction of high-density filtres or polymerase chain reaction (PCR) screening approaches. These BAC libraries will facilitate the positional cloning of quantitative trait loci (QTLs) for a variety of economically important traits in these species.     

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。     

Molecular,genetic and evolutionary analysis of a paracentric inversion in Arabidopsis thaliana

Chromosomal inversions can provide windows onto the cytogenetic, molecular, evolutionary and demographic histories of a species. Here we investigate a paracentric 1.17‐Mb inversion on chromosome 4 of Arabidopsis thaliana with nucleotide precision of its borders. The inversion is created by Vandal transposon activity, splitting an F‐box and relocating a pericentric heterochromatin segment in juxtaposition with euchromatin without affecting the epigenetic landscape. Examination of the RegMap panel and the 1001 Arabidopsis genomes revealed more than 170 inversion accessions in Europe and North America. The SNP patterns revealed historical recombinations from which we infer diverse haplotype patterns, ancient introgression events and phylogenetic relationships. We find a robust association between the inversion and fecundity under drought. We also find linkage disequilibrium between the inverted region and the early flowering Col‐FRIGIDA allele. Finally, SNP analysis elucidates the origin of the inversion to South‐Eastern Europe approximately 5000 years ago and the FRI‐Col allele to North‐West Europe, and reveals the spreading of a single haplotype to North America during the 17th to 19th century. The ‘American haplotype’ was identified from several European localities, potentially due to return migration.     

Microcloning of maize chromosome 9 by using a flow-sorting technique

We constructed a chromosome 9 lambda DNA library from flow-sorted maize chromosomes. Approximately 3 million maize chromosome 9 were collected with high purity by flow cytometric sorting of chromosomes isolated from an oat-maize chromosome 9 addition line based on the cytogram of fluorescent pulse area versus fluorescent pulse width. Chromosome 9 DNA was partially digested withBamH I, dephosphorylated, and ligated with arms ofBamH I-digested lambda DASH vector (Stratagene). A total of 2.0×10⁶ independent recombinants with an average insert size of 15 kb were obtained. For a 99% probability that every sequence of chromosome 9 is represented in at least one chimeric phage, 5.6×10⁴ cloned fragments are needed. This library covers the entire maize chromosome 9. Hybridizing cloned fragments with labeled maize genomic DNA showed that the high, middle, or low copy number DNA sequences presented in the different phage clones. This individual chromosome library is useful in plant genome mapping and gene isolation.     

The chromosomes ofCunninghamia konishii,C. lanceolata,andTaiwania cryptomerioides (Taxodiaceae)

Karyotype analyses were conducted onCunninghamia konishii, Cunninghamia lanceolata, andTaiwania cryptomerioides, all members ofTaxodiaceae. The somatic chromosome number was found to be 2n = 2x = 22 in all species which concurrs with previous reports. The karyotypes are generally asymmetrical with the smaller chromosomes being more submedian than the larger ones. Chromosomes with unusual or specific structures, thought to be associated with the nucleolar organizing region, were found in each species.Cunninghamia species have a marker chromosome pair with an unusually long secondary constriction.Taiwania has an unusually long kinetochore region present in a submedian chromosome pair.     

利用染色体片段置换系定位水稻落粒性主效QTL

水稻落粒性是与其生产密切相关的重要性状之一。以7个染色体片段置换系为材料,采用重叠群代换作图法对控制落粒性的2个主效QTL进行定位。结果表明,104个SSR标记在亲本间具有多态性,多态率为68.0%;4个置换系的落粒性与亲本日本晴的落粒性相似,表现难落粒。3个置换系与亲本93-11的落粒性相似,表现易落粒;7个染色体片段置换系在第1和第6染色体上检出7个置换片段,其长度分别为23.6、16.5、6.6、9.9、10.4、20.2和7.1 cM;qSH-1-1被定位在第1染色体RM472-RM1387之间,遗传距离约为6.6 cM。qSH-6-1为新发现的落粒性主效QTL,被定位在第6染色体RM6782-RM3430之间,遗传距离约为4.2 cM。利用染色体片段置换系能准确地定位水稻落粒性QTL,qSH-1-1与qSH-6-1的鉴定和初步定位为其进一步的精细定位、图位克隆及分子标记辅助选择奠定了基础。