花背蟾蜍的核型分析 Ⅰ.花背蟾蜍的血淋巴细胞培养及其核型分析

采用淋巴细胞培养的方法,分析了花背蟾蜍的核型,并与中华大蟾蜍进行了比较。与蟾蜍属的多数物种一样,花背蟾蜍的2n也是22,由6对大染色体和5对小染色体构成,各对染色体之间在形态上可以区分。花背蟾蜍与中华大蟾蜍在核型上有微小而又重要的差别,主要涉及核仁组织者的位置和第10染色体。应当特别指出的是,与蟾蜍属的其它物种不同,花背蟾蜍的NoR染色体是第4染色体。在分析正常核型的同时,还发现了自发畸变的有丝分裂相,畸变率约为1％。     

四川卧龙自然保护区华西蟾蜍的核型和Ag-NORs研究

采用常规骨髓细胞制片法对产于卧龙自然保护区华西蟾蜍的核型及Ag-NORs位点进行了观察和分析.结果 表明卧龙自然保护区蟾蜍与大部分蟾蜍相同:2n=22,NF=44,为6+5核型模式.核型为20M+2SM,次缢痕较为明显,位于第6对染色体(其中的一条)长臂末端,NORs位于次缢痕位置即6qter.通过与我国中华蟾蜍种组的核型及Ag-NORs位点等细胞学信息比较分析,不支持卧龙自然保护区卧龙蟾蜍和沙湾蟾蜍为有效种,其可能是华西蟾蜍的次级同物异名.     

哀牢蟾蜍和新疆绿蟾蜍的核型、C-带和Ag-NORs

本文报道了云南的哀牢蟾蜍和新疆绿蟾蜍的核型、C-带和Ag-NORs。新疆绿蟾蜍2n=44(36M+8SM),NF=88,除Nos.7,8,13,14四对是SM外,其余诸对均为M,一对随体和Ag-NORs位于12q ter,C-带位于全部染色体的着丝点区域,随体位置也显示C-带,并有少数不稳定的端位和插入型C-带。推测它可能是来自欧洲绿蟾蜍的老四倍体类型。哀牢蟾蜍2n=22(20M+2SM),NF=44,其中只有No.7为SM,一对Ag-NORs和随体位于6q ter,但该区域不着染C-带;全部染色体的着丝点显示不同程度的C-带正染;本种未发现与性别相关的异形染色体。最后,文中讨论了蟾蜍属的核型演化机制。     

花背蟾蜍的染色体组型

sato, I.最早对花背蟾蜍的染色体作过研究并有记载。此后,在国内亦见有报道(毛铭廷1976)。但是,由于他们的技术和方法所限,未能达到准确地分析染色体组型和测量统计染色体的相对长度,臂比指数和着丝点位置。因而,随着血培养技术的应用,本文对其染色体作了进一步的研究。     

黑眶蟾蜍、黑斑蛙、中国雨蛙不同地理居群的染色体多样性

本文研究温州地区的黑眶蟾蜍、黑斑蛙、中国雨蛙的核型,分析了三个地理居群的黑眶蟾蜍、四个地理居群的黑斑蛙、三个地理居群的中国雨蛙核型.结果表明不同地理居群的同种蛙有相同的染色体数和核型模式.黑眶蟾蜍为2n=22,NF=44,核模式6+5;黑斑蛙为2n=26,NF=52,核模式5+8;中国雨蛙为2n=24,NF=48,核模式6+6.但同一种蛙的不同地理居群之间在SM数目和顺序、次缢痕或随体的位置等有所不同.说明不同地理居群的同种蛙的染色体具有丰富的多样性.     

脂肪细胞分化差异表达基因与其染色体所在遗传图位置的相关性分析

在脂肪细胞分化过程中,有约1／3表达的基因被诱导或抑制。通过分析3T3－L1脂肪细胞分化差异表达基因在染色体遗传图上的位置,对共同表达诱导或抑制的基因群体的调控与它们在染色体遗传图上的位置分布的关系进行分析。结果显示这些共同调控的基因除拥有共同的转录调控因子外,未发现在染色体的位置上和它们的共同调控有相关性。     

黑眶蟾蜍、黑斑蛙、中国雨蛙不同地理居群的染色体多样性

本文研究温州地区的黑眶蟾蜍、黑斑蛙、中国雨蛙的核型,分析了三个地理居群的黑星期五蟾蜍、四个地理居群的黑斑蛙、三个地理居群的中国雨蛙核型。结果表明不同地理居群的同种蛙有相同的染色体数和核型模式。黑星期五蟾蜍为2n＝22,NF＝44,核模式6＋5;黑斑蛙为2n=26,NF=52,核模式5＋8;中国雨蛙为2n＝24,NF＝48,核模式6＋6。但同一种蛙的不同地理居群之间在SM数目和顺序、次缢痕或随体的位置等有所不同。说明不同地理居群的同种蛙的染色体具有丰富的多样性。     

移植非洲爪蟾胚胎细胞核引起花背蟾蜍成熟卵单性发育的研究

将非洲爪蟾胚胎细胞核移入花背蟾蜍成熟未受精卵后,得到了发育至各期的胚胎。对发育不同的时期的胚胎,进行了乳酸脱氢酶同工酶谱及染色体组型分析,结果一显示其均与受体一致。根据实验分析认为,非洲爪蟾的胚胎细胞进入花背蟾蜍成熟卵后,引起的是花背蟾蜍的单性发育。     

海蟾蜍——不断升级的入侵种

蟾蜍,是一种通过特化出毒腺以求自保的两栖动物.它们种类众多,全球分布很广.现今在澳大利亚,活跃着一种体型巨大而又贪吃的蟾蜍——海蟾蜍.它们是无尾目里第三大、也是蟾蜍家族中体型最大的物种,最大个体肛吻距将近40厘米.如今海蟾蜍在澳大利亚的泛滥同时不断进化,引发了当地十分严重的生态问题.     

中华大蟾蜍和花背蟾蜍染色体同源性研究

本文以培养 扣华大蟾蜍、花背蟾蜍的外周血淋巴细胞为实验材料,采用ＢｒｄＵ南极洲民法和胸苷标记的方法,获得了中华大蟾蜍与花背蟾蜍析搞分辨晚复制带,确定了中华大蟾蜍每一染色体的特征性晚复制区,并就中华大蟾蜍与花背蟾蜍的晚复纹带进行了精确比较,发现中华大蟾蜍与花背蟾蜍的染色体之间具有极高同源性,该结果说明,在相同的培养条件下,只要ＢｒｄＵ掺入Ｓ期的时间较为统一,显示复制带的条件基本一致的情况下,利用复     

Chromosome characterization and biogeographic relations among three populations of the driftwood catfish Parauchenipterus galeatus (Linnaeus, 1766) (Siluriformes: Auchenipteridae) in Brazil

The present study employed basic and molecular cytogenetic methods to characterize three populations of Parauchenipterus galeatus from the basins of the Paraná and São Francisco Rivers, and a region of connection between the two basins. Although the diploid number was equal to 58 chromosomes, variations in karyotype formula were detected among the populations. B chromosomes were detected only in the population from the São Francisco River. Heterochromatin was located in the terminal position in almost all the chromosomes and in the pericentromeric position in some acrocentric chromosomes in the three populations. A single nucleolus organizer region was detected by silver nitrate and 18S rDNA‐fluorescent in situ hybridization in the short arm of one subtelocentric pair in the three populations, varying only in the chromosome pair bearing this site. The 5S rDNA sites were located in two submetacentric chromosome pairs in the three populations, varying only in the chromosome pairs bearing these sequences. Classic and molecular chromosome markers, along with the context of the natural history of the formation of hydrographic basins, ecological aspects, and the geographic isolation of populations between hydrographic basins and within the same basin, were important contributions to the discussion on possible biogeographic relations among the populations of Parauchenipterus galeatus. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 648–656.     

A new chromosomal race (2n=44) of Nannospalax xanthodon from Turkey (Mammalia: Rodentia)

A new karyotype for blind mole rats was recorded in Tunceli province in Eastern Turkey. The karyotype contained 44 chromosomes, including 13 biarmed pairs, 7 acrocentric pairs, and one heteromorphic pair with a submetacentric and an acrocentric homologue in the autosomal complement (FNa=69). The X chromosome was submetacentric and the Y chromosome medium-sized subtelocentric (FN=73). Distinct dark centromeric C-bands were observed on most of the biarmed and three pairs of the acrocentric autosomes. The NORs were detected on short arms of three subtelocentric pairs and one acrocentric pair of autosomes. The diploid number of chromosomes and the karyotype characteristics observed are obviously unique among hitherto studied populations of blind mole rats and the complement can be evaluated as a new chromosome race of Nannospalax xanthodon. The distribution ranges of individual chromosome races of the species recorded in Eastern Anatolia are revised and possible interracial hybridization is discussed in respect of the finding of a new race.     

COMPARATIVE ANALYSIS OF KARYOTYPES AND NUCLEOLAR ORGANIZER REGIONS IN DIFFERENT POPULATIONS OF MYTILUS TROSSULUS, MYTILUS EDULIS AND MYTILUS GALLOPROVINCIALIS

The cylotaxonomical characteristics of Mytilus tros-sulus, M.edulis and M. galloprovincialis were studied using karyometricanalysis and silver staining. The karyotype of M. trossulus,reported here for the first time, consists of six metacentricand eight submetacentric-subtelocentric chromosome pairs. Theoccurrence of five metacentric chromosome pairs in M. galloprovincialisdifferentiates this taxon from M. trossulus and M. edulis whichboth have six meta-centrics. The number of submetacentric tosubtelo-centric chromosome pairs was variable between populationsand between taxa. We suggest that this variability has arisenfrom differential chromosome condensation rather than from structuralchange. Intercomparison of chromosome relative length showedstrong similarity among the three taxa. Chromosomal nucleolarorganizer regions (NORs) were identically located on two submetacentric-subtelocentricchromosome pairs in all three taxa. However, M. trossulus showeda characteristic difference in the occurrence of NORs on onemetacentric pair, which was absent in M. galloprovincialis andM. edulis. Variability in the number of NORs per cell was observedin all populations studied. We conclude that the three taxaof Mytilus studied here cannot be differentiated by asinglekaryological character, but that a combination of karyologicalcharacters is virtually diagnostic ^* To whom correspondence should be sent (Received 24 January 1994; accepted 9 March 1994)     

Genetic Diversity and Linkage Disequilibrium in Drosophila melanogaster with Different Rates of Development

We have examined eight enzyme polymorphisms in groups of Drosophila melanogaster flies with fast, intermediate and slow development. The allelic frequencies are similar in all three developmental classes, but the distribution of the genotypes among the classes is significantly heterogenous for the three loci on the second chromosome. When the total sample of 300 individuals is examined, significant gametic disequilibrium appears in 3 out of 13 pairs of genes located on the same chromosome and in 4 out of 15 pairs of genes located on different chromosomes. This 25% incidence of disequilibrium between pairs of genes is larger than previously observed in other natural populations (but similar to the incidence observed in laboratory populations). The greater frequency of significant gametic disequilibrium in our study is probably due to the larger number of genomes sampled.-Some models specifically predict that individuals with faster rates of development (i.e., greater fitness) should be more heterozygous (and exhibit more linkage disequilibrium) than individuals with slower development. This hypothesis is not supported by our results.     

Karyological studies of two populations of Juniperus communis L. in west Siberia

Results of a karyological study of Juniperus communis L. populations under swamp and dry conditions are presented. The chromosome number of J. communis are 2n = 22. Analysis of morphological chromosome parameters showed a similarity between karyotypes of both populations. It is possible to identify one pair of asymmetric chromosomes (VIII pair); this chromosome pair is close to submetacentric type. Three pairs of chromosomes (I, VII, VIII) have secondary constrictions. Other metacentric chromosomes form groups of five long (II--VI) and three short (IX-XI) pairs. Differences between two populations in absolute chromosomal length are observed.     

Chromosomal variability of the field mouse Apodemus agarius (Rodentia, Muridae)

Chromosome sets of 114 Apodemus agrarius mice from 29 localities in Moldova, Ukraine, Siberia, and Far East were studied by means of G-, C-, and NOR-banding. In all populations studied, the Y chromosome was shown to be a medium-size acrocentric chromosome consisting of heterochromatin. Chromosome polymorphism observed in populations from Primorskii krai concerned (1) the morphology of the first two autosome pairs (variants A/A, A/ST, and ST/ST), (2) the number of metacentric chromosomes (from 6 to 8), and (3) heterochromatin localization in the pericentromeric regions of two metacentric chromosome pairs. A karyotype with an additional heterochromatic microchromosome found in all the metaphases studied was described in one mouse from a locality of western Primorye that has not been studied previously. In the karyotype of 15 mice from four populations of Primorye, the pool of nucleolus organizer regions is distributed over three autosome pairs rather than over four, as is the case A. agrarius from Europe. Based on the analysis of literature sources and our own data, the problem of chromosome polymorphism in the field mouse is discussed.     

蛾螺科三种螺的核型观察

本文介绍了蛾螺科三种螺的核型。水泡蛾螺(Buccinum pcmphigum)为2n=30,染色体的形态分类组成为16m+10sm+4st,NF=56;Plicifusus scissuratus为2n=34,染色体的形态分类组成为20m+10sm+4st,NF=64;香螺(Neptumea cumingi)为2n=60,染色体的形态分类组成为30m+22sm+8st,NF=112。 蛾螺科核型分析,显示贝类染色体数目及其形态与贝类进化有关。     

Karyological analysis of two allopatric populations of planarian Polycelis felina (Daly.) in Croatia

The results of preliminary karyological investigations of two geographically distant and morphologically slightly different Polycelis felina (Daly.) populations from central Croatia are reported. The results have shown that individuals of both populations are diploids, with the same chromosome number in their neoblasts (2n=18). Their karyotypes were composed of nine chromosome pairs, three of them are metacentric and the other six are submetacentric. Statistical evaluation of data indicated that both populations of Polycelis felina (Daly.), despite minor differences observed between them, belong to the same karyological biotype.     

Chromosomes of tuatara, Sphenodon, a chromosome heteromorphism and an archaic reptilian karyotype

We examined karyotypes of the endemic New Zealand reptile genus Sphenodon (tuatara) from five populations, finding a karyotype unchanged for at least one million years. Animals karyotyped were from five geographically distinct populations, representing three groups, namely S. guntheri, S. punctatus (Cook Strait group), and S. punctatus (northeastern North Island group). All five populations have a diploid chromosome number of 2n = 36, consisting of 14 pairs of macrochromosomes and four pairs of microchromosomes. Chromosomal differences were not found between the five populations nor between female and male animals, except for one animal with a structural heteromorphism. Similarity between Sphenodon and Testudine karyotypes suggests an ancestral karyotype with a macrochromosome complement of 14 pairs and the ability to accumulate variable numbers of microchromosome pairs. Our research supports molecular phylogenies of the Reptilia.     

Chromosome banding and essential oils composition of Brazilian accessions of <Emphasis Type="Italic">Lippia alba</Emphasis> (Verbenaceae)

The essential oil components and a karyotypic analysis of five Lippia alba (Verbenaceae) accessions from Brazil were performed with the objective of investigating the variation among different populations. The chemistry analysis allowed the grouping of the accessions in two main chemotypes: neral chemotype (LaCat, LaJF and LaRJ) and linalool chemotype (LaGua and LaVC). However, large karyotypic differences, verified by different chromosome banding techniques, were not detected. The results presented the same chromosome number for all accessions (2n = 30) with 10 metacentric chromosomes and 5 submetacentric. The chromosome banding showed great blocks of constitutive heterochromatin (C-bands) around the centromeric region, which was rich in AT bases (DAPI₊), while the CMA bands were observed only in terminal regions of six chromosomes. Through Ag-NOR techniques, only two active pairs of NORs were detected on the three pairs of secondary constrictions (the NOR activity is discussed). This work relates the pattern of heterochromatin for Lippia alba for the first time.