兴义维蚋多线染色体研究（英文）

首次在国内对兴义维蚋Simulium (Wilhelmia) xingyiense的多线染色体进行研究, 并提供其多线染色体标准图。选取兴义维蚋的成熟幼虫, 用改良苯酚品红染色法进行唾腺多线染色体制备, 并进行测量、 描述及分析。结果表明： 兴义维蚋多线染色体数目为3对（2n=6）。Ⅰ号染色体具中央着丝粒, Ⅱ和Ⅲ号染色体均为亚中央着丝粒染色体。核仁组织者区位于Ⅰ号染色体短臂近着丝粒端。巴尔比尼氏环和双泡位于Ⅱ号染色体短臂近中央位置。3对染色体的着丝粒区可形成明显的染色中心。兴义维蚋多线染色体具有多态性的倒位, 倒位频率为0.64。兴义维蚋多线染色体的着丝粒、 核仁组织区、 巴氏环、 双泡等主要特征性结构的位置及形态恒定一致,可作为该种的重要鉴别特征。其多态性的倒位可为该蚋种在细胞水平上进行蚋类分类鉴别和系统发育等研究提供基础资料。     

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.     

太谷发现2n=4毛足雕翅摇蚊

毛足雕翅摇蚊Glyptotendipes barbipes (Staeger)最早由H. Bauer引人细胞遗传学 研究。H. Bauer发现,该物种唾腺染色体具深 染色的呈鼓形的异染色质区,这种异染色质区 代表着丝粒位置;染色体组由三对长的中着丝 粒染色体和一对端着丝粒染色体组成［[31。此 后,人们对分布于欧洲、苏联和北美的·G. barbi pe,不同种群唾腺染色体斑带模式进行了分 析,证明该物种为一具高度倒位多态性的物 种[4-810但是,上述研究中并未发现染色体数目 的变异,即该物种具有摇蚊科典型的染色体数 目,2。～ 8-     

果蝇幼虫唾腺染色体标本的制备与比较

唾腺染色体是最早发现于双翅目昆虫唾腺细胞的一种巨大染色体,现已广泛应用于细胞遗传、基因定位等研究中。用黑腹果蝇3龄幼虫为材料,压片法制备染色体标本,并对3种品系果蝇幼虫的唾腺染色体的形态结构进行比较。结果表明:果蝇唾腺染色体臂端粒端的横纹特征基本恒定,是辨认各染色体臂的最便捷方法;黑腹果蝇的3种品系果蝇幼虫在唾腺染色体横纹的宽窄、数目、排列顺序及疏密程度上不存在明显的差异,在不同变种之间无法区分。     

尼罗罗非鱼染色体的C带、Ag带和减数分裂联会复合体的研究

以Sumner法和界面铺张——硝酸银技术,对尼罗罗非鱼(Tilapia nilotica)染色体C带、Ag染带及减数分裂前期精母细胞联会复合体(SC)进行了显微和亚显微结构观察。 尼罗罗非鱼的2n=44,核型可分为三个组:第一组为4对亚中着丝粒染色体;第二组为17对亚端着丝粒染色体;第三组为具1对端着丝粒的特大染色体。 结构异染色质主要分布于着丝粒附近,其中Nos.6、8、15亚中着丝粒染色体短臂全部深染。带有银染核仁组织者(Ag-NORs)染色体的数目为2—6条,NORs均位于6、8、15亚中着丝粒染色体短臂。 银染色可清楚地显示尼罗罗非鱼的联会复合体(SC)结构和减数分裂行为。SC组型与有丝分裂染色体的组型有较好的一致性。     

尼罗罗非鱼染色体的C带,Ag带和减数分裂联合复合体的研究

以Sunmer法和界面铺张——硝酸银技术,对尼罗罗非鱼（Tilapia nilotica）染色体C带,Ag染带及减数分裂前期精母细胞联会复合体（SC）进行了显微和亚显微结构观察。尼罗罗非鱼的2n=44,核型可分为三个组：第一组为4对亚中着丝粒染色体;第二组为17对亚端着丝粒染色体;第三组为具1对端着丝粒的特大染色体。结构异染色质主要分布于着丝粒附近,其中Nos.6、8、15亚中着丝粒染色体短臂全部深染。带有银染核仁组织者（Ag-NORs）染色体的数目为2-6条,NORs均位于6、8、15亚中着丝粒染色体短臂。银染色可清楚地显示尼罗罗非鱼的联会复合体（SC）结构和减数分裂行为。SC组型与有丝分裂染色体的组型有较好的一致性。     

习惯性流产伴罕见Rob(13;21)的异常核型分析

病例　　患者,女,29岁,汉族,身高156cm,体重52kg;职业农民表型无异常,非近亲婚配,否认家族遗传史。孕期及孕前期无毒物、化学、放射物的接触史,无特殊病史。因连续流产4次而就诊。细胞遗传学检查　　外周血染色体分析,普通核型计数,分析50个分裂相,均为45条,D、G组各少一条,多一条衍生染色体。经G带技术分析了20个核型均为45,XX,der(13;21)(q10;q10)。其丈夫核型正常,其他家庭成员拒绝检查。患者的13号、21号染色体分别在着丝粒区发生断裂,两者的长臂在着丝粒区附近彼此连接,形成了一条新的染色体,两者的短臂也可能连接成一条小染色体…     

鳙鱼染色体的DAPI核型分析

利用腹腔注射秋水仙素制备肾细胞染色体方法和DAPI（4＇,6＇-diamidino-2-phenylindole）荧光染色的方法,对鳙鱼（Aristichthys,nobills）的染色体组型和染色质的分布进行了研究。结果表明,其二倍体数目为2n=48,核型为30M＋14SM＋2ST＋2T。DAPI荧光染色显示间期细胞核中荧光亮度较为一致,提示异染色质在间期细胞核中分布比较均一。而DAPI荧光染色在第1和第4染色体的短臂上较为明亮,其余染色体上的明亮区都分布在着丝粒区域,表明第1和第4染色体上的异染色质主要集中在染色体的短臂上,其余染色体的异染色质主要分布在着丝粒区域。     

玉米mir1基因在玉米和薏苡中的比较物理定位

玉米基因mir1编码一种抗秋季黏虫的半胱氨酸蛋白酶。利用RFLP作图mir1基因被定位在玉米第 6号染色体短臂上 ,但它在第 6号染色体短臂上的物理位置还不知道。实验以mir1和 4 5SrDNA为探针 ,通过双色荧光原位杂交技术确定了mir1基因在玉米细胞分裂中期和粗线期第 6号染色体上的物理位置。Southern杂交结果表明 ,在薏苡基因组中存在mir1基因的同源序列 ,进一步利用荧光原位杂交的方法确定mir1基因的同源序列定位于薏苡第 7号染色体长臂的近末端 ,其信号与着丝粒的百分距离为 73 33± 0 15。     

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。     

Identification and designation of telocentric chromosomes in barley by means of Giemsa N-banding technique

Summary Seven complete chromosomes and nine telocentric chromosomes in telotrisomics of barley (Hordeum vulgare L.) were identified and designated by an improved Giemsa N-banding technique. Karyotype analysis and Giemsa N-banding patterns of complete and telocentric chromosomes at somatic late prophase, prometaphase and metaphase have shown the following results: Chromosome 1 is a median chromosome with a long arm (Telo 1L) carrying a centromeric band, while short arm (Telo 1S) has a centromeric band and two intercalary bands. Chromosome 2 is the longest in the barley chromosome complement. Both arms show a centromeric band, an intercalary band and two faint dots on each chromatid at middle to distal regions. The banding pattern of Telo 2L (a centromeric and an intercalary band) and Telo 2S (a centromeric, two intercalary and a terminal band) corresponded to the banding pattern of the long and short arm of chromosome 2. Chromosome 3 is a submedian chromosome and its long arm is the second longest in the barley chromosome complement. Telo 3L has a centromeric (fainter than Telo 3S) and an intercalary band. It also shows a faint dot on each chromatid at distal region. Telo 3S shows a dark centromeric band only. Chromosome 4 is the most heavily banded one in barley chromosome complement. Both arms showed a dark centromeric band. Three dark intercalary bands and faint telomeric dot were observed in the long arm (4L), while two dark intercalary bands in the short arm (4S) were arranged very close to each other and appeared as a single large band in metaphase chromosomes. A faint dot was observed in each chromatid at the distal region in the 4S. Chromosome 5 is the smallest chromosome, which carries a centromeric band and an intercalary band on the long arm. Telo 5L, with a faint centromeric band and an intercalary band, is similar to the long arm. Chromosomes 6 and 7 are satellited chromosomes showing mainly centromeric bands. Telo 6S is identical to the short arm of chromosome 6 with a centromeric band. Telo 3L and Telo 4L were previously designated as Telo 3S and Telo 4S based on the genetic/linkage analysis. However, from the Giemsa banding pattern it is evident that these telocentric chromosomes are not correctly identified and the linkage map for chromosome 3 and 4 should be reversed. One out of ten triple 2S plants studied showed about 50% deficiency in the distal portion of the short arm. Telo 4L also showed a deletion of the distal euchromatic region of the long arm. This deletion (32%) may complicate genetic analysis, as genes located on the deficient segment would show a disomic ratio. It has been clearly demonstrated that the telocentric chromosomes of barley carry half of the centromere. Banding pattern polymorphism was attributed, at least partly, to the mitotic stages and differences in techniques.Contribution from the Department of Agronomy and published with the approval of the Director of the Colorado State University Experiment Station as Scientific Series Paper No. 2730. This research was supported in part by the USDA/SEA Competitive Research Grant 5901-0410-9-0334-0, USDA/ SEA-CSU Cooperative Research Grant 12-14-5001-265 and Colorado State University Hatch Project. This paper was presented partly at the Fourth International Barley Genetics Symposium, Edinburgh, Scotland, July 22–29, 1981     

Regulation of rRNA gene expression in a human familial 14p+ marker chromosome

Summary Chromosome studies were carried out on normal individuals from three generations of one family with a 14p+ chromosome. The short arm of the 14p+ chromosome stained well using Giemsa but poorly using quinacrine or trypsin-Giemsa methods; in each case there was an unstained secondary constriction near the distal end of the short arm. Two Ag bands of average size were present on the 14p+ short arm, indicating that there were two active nucleolus organizer regions; the Ag band near the distal end of the short arm was slightly larger than that near the centromere. Each of the two Ag bands was seen associated with the short arm of one or more of the other acrocentric chromosomes, with a combined frequency of association no greater than that of other chromosomes with an Ag band of the same size. In one individual, hybridization in situ with radioactive 18S and 28S ribosomal RNA showed six times as many autoradiographic silver grains over the short arm of the 14p+ chromosome as over that of any other acrocentric chromosome. The results obtained using in situ labeling indicated that the 14p+ chromosome had a large number of rRNA genes compared with the other acrocentric chromosomes, whereas the results obtained using Ag-staining and association frequency indicated that the 14p+ chromosome had no greater nucleolus organizer activity than did the other acrocentrics. The difference in these findings suggests that not all the rRNA genes on the 14p+ chromosome were active.     

G and C banding show structural differences between the Z and W chromosomes in the frog Buergeria buergeri

G and C banding studies were made on cultured blood cells of matured male and female Buergeria (B.) buergeri frogs. The Z is subtelocentric and the W is submetacentric. There is a satellite near the end of the long arm of the Z. Constitutive heterochromatin is seen near the proximal and distal portions of the long arms of both Z and W. A single heavily stained G band is seen in the short arm of Z, while one or two heavily stained G bands are observed in the short arm of W. The Z may have originated through a process, in the course of which parts of W have been translocated to Z.     

Modeling dark puffs using P-transposons in Drosophila melanogaster polytene chromosomes

Modeling of morphologically unusual "dark" puffs was conducted using Drosophila melanogaster strains transformed by construct P[ry; Prat:bw], in which gene brown is controlled by the promoter of the housekeeping gene Prat. In polytene chromosomes, insertions of this type were shown to form structures that are morphologically similar to small puffs. By contrast, the Broad-Complex (Br-C) locus, which normally produce a dark puff in the 2B region of the X chromosome, forms a typical light-colored puffs when transferred to the 99B region of chromosome 3R using P[hs-BRC-z1]. A comparison of transposon-induced puffs with those appearing during normal development indicates that these puff types are formed via two different mechanisms. One mechanism involves decompaction of weakly transcribed bands and is characteristic of small puffs. The other mechanism is associated with contacts between bands adjacent to the puffing zone, which leads to mixing of inactive condensed and actively transcribed decondensed material and forming of large dark puffs.     

Formation and morphology of dark puffs in Drosophila melanogaster polytene chromosomes

The formation of unusual dark puffs in Drosophila melanogaster polytene chromosomes has been studied by electron microscopic (EM) analysis. Fly stocks transformed by the P[ry; Prat:bw] and P[hs-BRC-z1] constructs were used. In the former the bw gene is under the promoter of a housekeeping gene, Prat; in the latter the Br-C locus, mapping to the dark puff 2B, is under the promoter of a heat-shock gene, hsp70. Inserted into region 65A of the 3L chromosome, the Prat:bw copies give rise to structures which are morphologically reminiscent of the so-called "dark" puffs. In contrast, insertion of P[hs-BRC-z1] into region 99B of the 3R chromosome causes a regular "light" puff of form. Comparative analysis of the dark puffs--both transgenic and natural--suggests that there might be at least two mechanisms underlying their formation. One is a local incomplete decondensation of activated bands, characteristic of the so-called small puffs. The other is the formation of ectopic-looking contacts between the bands adjacent to the puffing zone. Transposition of the DNA, from which such a puff develops, causes a regular light puff to form at the new location. Heterochromatic regions do not appear to be directly involved in puffing.     

Senescence and human chromosome changes

Summary A girl with slight psychomotor retardation, microphthalmia, and colobomata of the left eye, a hypotrophy of the right arm and a surnumerary digit on the right hand is described. The routine chromsome analysis and a G-banding analysis revealed an elongated long arm of chromosome 10. An extra light and dark band was present proximally. Both parents had normal chromosomes. While the visual comparison of the abnormal with the normal chromosome 10, did not enable the extra bands of the normal bands q21 and q22 to be distinguished. However, measurements of length, surface area, and relative reflection of the different light and dark bands of the long arm on tracings or directly on the normal and abnormal chromosomes, enabled us to precisely locate the extra bands and to determine that the abnormal chromosome was a result of an insertional translocation. The value of such measurements is discussed.     

串叶松香草Giemsa C带和染色中心研究

以Giemsa C带技术处理串叶松香草根尖细胞染色体(2n=14),全部着丝点及第5和第7对染色体短臂端部显稳定的C带,第6对染色体长臂有两条明显的居间带,其他居间带小而不稳定(重复率不高)。间期细胞核染色体呈Rable构型,其着丝点一极最多出现20个染色中心。统计分析表明,靠近着丝点的短臂端带区和居间带区异染色质有易与着丝点区异染色质融合的倾向。分裂中期Giemsa C带数目与间期染色中心数目存在数量对应关系。     

Centric fission consequences in man

The authors summarise the consequences of centric fission in man as follows: classical (monocentric) isochromosomes; usually either for p or q, exceptionally for both arms; stable telocentrics for either one or both arms; isochromosome for one arm, stable telocentric for the other; isochromosome for one arm concurring with translocation of the telocentric for the other; telocentric/isochromosome mosaicism for the same arm; stable telocentric for a part of one arm, the remaining of the chromosome forming a smaller element (obviously this rearrangement requires an additional break outside the centromere), and whole-arm translocations. These events are discussed in the light of current notions about centromere structure and function.     

Modeling of Dark Puffs Using P Transposons in Polytene Chromosomes of Drosophila melanogaster

Modeling of morphologically unusual dark puffs was conducted using Drosophila melanogaster strains transformed by construct P[ry; Prat:bw], in which gene brown is controlled by the promoter of the housekeeping gene Prat. In polytene chromosomes, insertions of this type were shown to form structures that are morphologically similar to small puffs. By contrast, the Broad-Complex (Br-C) locus, which normally produce a dark puff in the 2B region of the X chromosome, forms a typical light-colored puff when transferred to the 99B region of chromosome 3R using P[hs-BRC-z1]. A comparison of transposon-induced puffs with those appearing during normal development indicates that these puff types are formed via two different mechanisms. One mechanism involves decompaction of weakly transcribed bands and is characteristic of small puffs. The other mechanism is associated with contacts between bands adjacent to the puffing zone, which leads to mixing of inactive condensed and actively transcribed decondensed material and forming of large dark puffs.     

De novo (11;13) translocation.

A male infant is described with unusual facial appearance, clubfeet, and moderate hydrocephalus internus without obvious deficiency in mental and physical development. Cytogenetic studies revealed a karyotype of 45,XY,--C,--D,+t(C;D). A chromosome 11 and a 13 are involved in the formation of the translocation chromosome. The long arm of chromosome 13 is linearly attached to the end of the long arm of chromosome 11 (tandem translocation). Chromosome material of the distal part of the long arm of chromosome 11, as well as the short arm plus the centromere of chromosome 13 seem to have been lost.