Mapping of18-26S rDNA loci in four species of the genus Paris by fluorescence in situ hybridization（FISH）

18-26S rDNA loci were mapped on chromosomes in four species of Par is,and the num-ber and position of rDNA sites in these species were compared f or analysis of the distribution of the sites. All the plants were diploids,and t he genome consisted of five chromosomes,A,B,C,D and E. （1）P. polyphylla var. yunnanensis,2n=10=6m+4t. Two18-26S rDNA loci were de-tected on the short arms o f C and D chromosomes;（2）P. forrestii,2n=10=6m+4t. One locus was detected on th e long arm of B chromosome,and also two loci on the short arms of C and D chromosomes;（3）P. axialis. 2n=10=6m（2sat）+4t（2sat）+1-2B. Two loci were detected o n the short arms of C and D chromosomes. One locus was detected in the cell with t wo B-chromosomes（B）,but none was detected in that with only one B chromosome, indicating that rRNA gene existed on B chromsome,and an unequal division occurr ed during mitotic cycle of B-chromosomes. （4）P. daliensis,2n=10=4m+2sm+2st+2t. O ne locus was detected on the short arm of D chromo-some. The signals of18-26S rD NA appeared not only in the second constriction but also in the other regions of chromosome. It is noteworthy that one locus was detected in the terminal region o n the short arm of C chromosome in all the four species studied.     

Variation of wheatgrass chromosomes in wheat-wheatgrass alien addition line “TAI-27” revealed by fluorescencein situ hybridization (FISH)

The Karyotyp of the primary wheat-whastgrass alien addition line TAI-27 was 2n = 44 in which all d the chromosomes were metacentric and subrmetacentric. However, in the progeny of TAI-27 a pair of chromosomes had become small chromosomea in the two morphologically different plants. Fluorescence in situ hybridizstionm (FISH) technique was used to analyze the two different plants. The observations indicate that a pair of small chromosomes in one varietion line are from wheatgrass. In another variation line, a pair of small chromosomes are also from whest-grass, while another pair of wheatgrass chromosomes have substituted the wheat chromosomes. TAI-27 and its variant lines showed a high level of resistance to barley yellow dwarf virus (BYDV). The pessible explanation for such a variation and the potential use of the variant lines were discussed briefly.     

Distribution of β2-like adrenergic receptors in the cnidarian Renilla koellikeri as revealed by autoradiography and in situ hybridization

Autoradiography and in situ hybridization were used to examine the histological distribution of the previously characterized 2-like adrenergic receptors involved in the bioluminescent activity of the sea pansy Renilla koellikeri. The use of [³H]-(±)CGP12177 as radiologand revealed autoradiographic labelling of the refringent granule-filled endoderm at the base of autozooid tentacles and autozooid columns, and in the corresponding endoderm of siphonozooid polyps, all areas where photocytes are concentrated. The presence of excess (10 M) unlabelled (±)CGP12177 or atenolol in the incubation mixture substantially reduced total [³H]-(±)CGP12177 labelling. Under low stringency hybridization washing, human 2-adrenoceptor oligonucleotide probe signals were detected in granular cells located in those areas of polyp endoderm that were labelled by [³H]-(±)CGP12177. These cells were previously shown to be distinct from, but in close proximity to photocytes. No other cell or tissue type was labelled in polyps or throughout colonial tissues. The results suggest that a conserved form of 2-adrenergic receptors is present and synthesized in a unique type of endodermal cell indirectly involved in sea pansy bioluminescence control.     

High-resolution mapping of YACs and the single-copy gene Hs1pro−1 on Beta vulgaris chromosomes by multi-colour fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) is a powerful approach for physical mapping of DNA sequences along plant chromosomes. Nematode-resistant sugar beets (Beta vulgaris) carrying aBeta procumbens translocation were investigated by FISH with two differentially labelled YACs originating from the translocation. At mitotic metaphases, the translocation was identified with both YACs in the terminal region on a pair of chromosomes. Meiotic chromosomes, representing a far more extended hybridization target, were used to determine the orientation of YACs with respect to chromosomal domains in combination with chromosomal landmark probes for telomeres and centromeres. The in situ detection of plant single-copy sequences is technically difficult, and the wild beet translocation was used to explore the potential resolution of the FISH approach and to introduce the chromosomal mapping of single-copy genes into genome analysis of Beta species. An internal fragment of the nematode resistance gene Hs1 ^pro–1, 684 bp long, was detected on both chromatids of different Beta chromosomes and represents one of the shortest unique DNA sequences localized on mitotic plant chromosomes so far. Comparative chromosomal mapping of the 684 bp Hs1 ^pro–1 probe in the translocation line, a monosomic addition line and in B. procumbens revealed the origin of the wild beet translocation leading to nematode-resistant sugar beets.     

Expression patterns of several floral genes during flower initiation in the apical buds of apple (Malus × domestica Borkh.) revealed by in situ hybridization

The apple (Malus?×?domestica Borkh.) is one of the commercially important fruit crops in the worldwide. The apple has a relatively long juvenile period (up to 4?years) and a long reproductive period between the flower initiation and the mature fruit (14?C16?months), which prevent the fruit breeding. Therefore, the understanding of the flowering system is important to improve breeding efficiency in the apple. In this study, to examine the temporal and spatial expression patterns of the floral genes, MdTFL1, MdAP1 (MdMASD5), AFL2, and MdFT, we conducted in situ hybridization analysis in the apple shoot apex. In vegetative phase, MdTFL1 was expressed on the rib meristem zone. When vegetative meristem began converting into inflorescence meristem, the expression level of MdTFL1 was drastically decreased. At the early stage of inflorescence meristem, the expression levels of AFL2, MdFT, and MdAP1 were up-regulated in the leaf primordia and the upper region of cell layers on the shoot apex. In late stage, the expression levels of AFL2 and MdAP1 were up-regulated in the young floral primordia. At a more advanced stage, high expression of MdAP1 was observed in the inflorescence primordium through the inner layer of sepal primordia and the outer layer of receptacle primordia and floral axis. Our results suggest that AFL2, MdFT, and MdAP1 affect to convert from the vegetative meristem into the inflorescence meristem after the decline of MdTFL1 expression. After that, AFL2 and MdAP1 promote the formation of the floral primordia and floral organs.     

Subspecies-specific intron length polymorphism markers reveal clear genetic differentiation in common wild rice （Oryza rufipogon L.） in relation to the domestication of cultivated rice （O. sativa L.）

It is generally accepted that Oryza rufipogon is the progenitor of Asian cultivated rice （O. sativa）. However, how the two subspecies of O. sativa （indica and japonica） were domesticated has long been debated. To investigate the genetic differentiation in O. rufipogon in relation to the domestication of O. sativa, we developed 57 subspecies-specific intron length polymorphism （SSILP） markers by comparison between 10 indica cultivars and 10 japonica cultivars and defined a standard indica rice and a standard japonica rice based on these SSILP markers. Using these SSILP markers to genotype 73 O. rufipogon accessions, we found that the indica alleles and japonica alleles of the SSILP markers were predominant in the O. rufipogon accessions, suggesting that SSILPs were highly conserved during the evolution of O. sativa. Cluster analysis based on these markers yielded a dendrogram consisting of two distinct groups： one group （Group I） comprises all the O. rufipogon accesions from tropical （South and Southeast） Asia as well as the standard indica rice; the other group （Group II） comprises all the O. rufipogon accessions from Southern China as well as the standard japonica rice. Further analysis showed that the two groups have significantly higher frequencies of indica alleles and japonica alleles, respectively. These results support the hypothesis that indica rice and japonica rice were domesticated from the O. rufipogon of tropical Asia and from that of Southern China, respectively, and suggest that the indica-japonica differentiation should have formed in O. rufipogon long before the beginning of domestication. Furthermore, with an O. glaberrima accession as an outgroup, it is suggested that the indica-japonica differentiation in O. ruffpogon might occur after its speciation from other AA-genome species.     

Chromosome mapping of the human cytidine-5′-triphosphate synthetase (CTPS) gene to band 1p34.1–p34.3 by fluorescence in situ hybridization

Summary The human cytidine-5-triphosphate synthetase (CTPS) gene was mapped by a direct mapping system combined with fluorescence in situ hybridization and replicated prometaphase R-bands. By high-resolution banding analysis, the signals were localized to band 34.1–34.3 of the short arm of chromosome 1; 1p34.1–p34.3. Simple procedures for the detection of R-bands are described.     

Relationships among Nicotiana species revealed by the 5S rDNA spacer sequence and fluorescence in situ hybridization

To investigate phylogenetic relationships in Nicotiana, the intergenic spacer sequences of 5S rDNA were analyzed in species with 2n=18, 20 or 24, and amphidiploid species with 2n=48. The chromosomal localization of the 5S rDNA was determined by fluorescence in situ hybridization (FISH). In species with 2n=24 and their descendants, a major 5S rDNA-specific PCR fragment of 400–650 bp was obtained. The amphidiploid species contained similar length of 5S rDNA units derived from putative diploid progenitors. Among the five clones from each representative PCR fragment, some nucleotide exchanges and length heterogeneity were observed. The latter was due to variation in the spacer region, such as differences in the length of poly A and/or poly T tracts as well as insertions/deletions. Interspecific comparisons of each 5S rDNA sequence demonstrated that the spacer sequence could be divided into three regions. Excluding gaps from the aligned spacer sequences of 5S rDNA, phylogenetic trees were constructed. Each phylogenetic tree showed an almost identical topology even if different algorithms were applied. The chromosomal locations of the 5S rDNA in each species correlated with the phylogenetic topology. The phylogenetic trees were generally in agreement with the current classification. Received: 15 January 2001 / Accepted: 15 February 2001     

黄褐棉45S rDNA的FISH定位及核型分析

黄褐棉是棉属5个四倍体棉种之一,利用荧光原位杂交技术将45S rDNA定位在黄褐棉2、4、9号染色体,2号染色体上的45S rDNA特别大,信号位于随体并覆盖了染色体的短臂,比二倍体和四倍体棉种的45SrDNA都要大得多;另外的2对信号很小,形状与陆地棉中的弱信号类似。黄褐棉的核型公式为：2n=4x=52=50m（2SAT）＋2sm,属于2B类型,第2对染色体为亚中着丝粒染色体,其余都为中部着丝粒染色体。黄褐棉的核型、随体数、45S rDNA与其他四倍体棉种区别很大,黄褐棉是一个非常特殊的四倍体棉种。     

花生45S rDNA和5S rDNA的染色体定位研究

对四粒红和蜀花四号花生材料进行了核型分析,四粒红为2B核型,核型公式为2n=4x=40=38m＋2sm（4SAT）;蜀花四号为1B核型,核型公式为2n=4x=40=40 m（2SAT）。利用双色荧光原位杂交技术,对45S rDNA和5S rDNA这两个材料有丝分裂中期染色体上的物理位置进行了定位分析。定位结果表明,四粒红有6对45S rDNA位点,位于A2L、A7S、A9L、B3L、B7S、B8L（A和B分别代表基因组A和基因组B,L和S代表长臂和短臂,数字代表染色体序号,下同）;2对5S rDNA位点,位于A3S和B3S;蜀花四号有5对45S rDNA位点,位于A2L、A9L、B3L、B7S、B9L;2对5S rDNA位点,位于A3S和B3S。花生的45S rDNA位点具有可变性,5S rDNA则相对保守。     

薏苡45S和5S rDNA的染色体定位研究(简报)

通过荧光原位杂交的方法确定了45S和5S正NA序列在薏苡前中期染色体上的位置.尽管具有20条染色体的薏苡是四倍体植物,但它的基因组中只有一个45S和5S rDNA位点.根据薏苡前中期染色体的核型,确定45S rDNA序列位于薏苡第2号染色体短臂上的次级缢痕区和随体上,5S rDNA序列位于第7号染色体长臂靠近着丝粒处,5S rDNA位点到着丝粒的百分距离是29.13±1.76.     

水稻45S rDNA和5S rDNA的染色体定位研究

45SrDNA和5SrDNA是水稻中与核糖体RNA合成有关的2个功能片段,有关这2个序列在水稻染色体上的位置,不同研究者的研究结果不尽相同,在获得水稻染色体清晰制片的基础上,通过FISH确定了45SrDNA序列位于水稻的第9号和第10号染色体的短臂末端,并且第9号染色体上的拷贝数多于第10号染色体,5SrDNA序列位于第11号染色体短臂靠近着丝点处。     

Chromosomal aberrations by fluorescence in situ hybridization (FISH)--Biomarker of exposure to carcinogenic PAHs

The fluorescence in situ hybridization (FISH) technique with whole chromosome painting for chromosomes #1 and #4 was used to study the impact of air pollution containing higher concentrations of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in three European cities, Prague (Czech Republic), Kosice (Slovakia) and Sofia (Bulgaria). In each site were followed an exposed group, who were police officers or bus drivers who work usually through busy streets for at least 8 h, and a reference group, who spent more than 90% of their daily time indoors.

In Prague, a significant increase was observed in percentage of aberrant cells (% AB.C.) in the police officers compared to the reference group (0.33 ± 0.25 versus 0.24 ± 0.18, p < 0.05). In Kosice, the exposed group differed from reference in the endpoints F_G/100 1.52 ± 1.18 versus 1.12 ± 1.30, p < 0.05; % AB.C. 0.30 ± 0.19 versus 0.21 ± 0.20, p < 0.05; t/1000 3.91 ± 3.18 versus 2.84 ± 3.10, p < 0.05. In Sofia were followed two exposed groups: police officers and bus drivers. All FISH endpoints were significantly higher in police officers compared to reference group (F_G/100 1.60 ± 0.99 versus 0.82 ± 0.79, p < 0.01; % AB.C. 0.25 ± 0.14 versus 0.13 ± 0.13, p < 0.01; t/1000 4.19 ± 2.65 versus 2.13 ± 2.05, p < 0.05; rcp 1.46 ± 1.07 versus 0.70 ± 0.76, p < 0.05). In bus drivers compared to reference there was an increase in % AB.C. (0.25 ± 0.18 versus 0.13 ± 0.13, p < 0.05).

This is the first study when FISH method was used to analyze the impact of environmental air pollution. According to the original hypothesis it is expected that the most important group of chemicals responsible for the biological activity of air pollution represent c-PAHs.     

栽培荞麦45S和5S rDNA的染色体物理定位研究

采用双色荧光原位杂交技术,对栽培荞麦甜荞和苦荞有丝分裂中期染色体上的45S和5S rDNA基因物理位置进行了定位分析。结果表明,甜荞有4对45S rDNA位点,位于ⅠS、ⅡS、ⅢL、ⅤL(L和S代表长臂和短臂,罗马数字代表染色体序号,下同);2对5S rDNA位点,位于ⅠL、ⅣS。苦荞有5对45S rDNA位点,位于ⅠS、ⅡS、ⅢL、ⅤL、ⅦS;3对5S rDNA位点,位于ⅠL、ⅣS、ⅥS。甜荞与苦荞的45S和5S rDNA位点具有明显的差异,显示其起源上关系较远。依据中期染色体45S和5SrDNA位点信息及经典核型特征,可以准确鉴别甜荞与苦荞8对同源染色体。     

18-26S rDNA在4种重楼属植物中的定位

为探讨rDNA在重楼属Paris L.中的分布规律,利用荧光原位杂交（FISH）对4种重楼属植物 的18-26S rDNA进行了定位。所有植物均为二倍体,基因组由A、B、C、D和 E5条染色体构成。（1）滇重楼P.polyphylla var.yunnanensis:2n=10=6m+4t,C和D染色体的 短臂上各有1个18-26S rDNA位点;（2）长柱重楼P.forrestii:2n=10=6m+4t,B染色体的长臂 、C和D染色体的短臂上各有1个位点;（3）五指莲P.axialis:2n=10=6m（2sat）+4t（2sat） +1-2B,C和D染色体的短臂上各有1个位点;在有1个B染色体的细胞中,B染色体没有信号点, 而有2个B染色体的细胞中,只有1个B染色体上有信号点,表明B染色体上有基因存在且其分裂 不均等;（4）大理重楼P.daliensis:2n=10=4m+2sm+2st+2t,C染色体的短臂上有1个位点。1 8-26S rDNA位点不仅出现在染色体的次缢痕上,也出现在非次缢痕位点。另外,4个种中C染 色体短臂末端均有18-26S rDNA。