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1.
The molecular cytogenetic organization of 17S ribosomal RNA genes (17S rDNA), a part of the 45S rDNA repeat, was investigated on the chromosomes of the liverwort Marchantia polymorpha using fluorescence in-situ hybridization (FISH). The numbers of 17S rDNA loci visualized in female and male chromosomes were ten and nine, respectively. This heterogeneous localization was due to the presence of an additional 17S rDNA locus on the X chromosome and its absence on the Y chromosome. The signal on the X chromosome covered almost the entire region of its long arm. The other nine signals were observed on the same loci of respective autosomes in both sexes. Southern hybridization analysis revealed an additional band including 17S rDNA exclusively on EcoRI digested female genomic DNA supporting the existence of an additional 17S rDNA locus on the X chromosome. 相似文献
2.
Genome size, karyotype, meiosis and a novel extra chromosome in Torenia fournieri, T. baillonii and their hybrid 总被引:1,自引:0,他引:1
Torenia is a suitable model plant to study plant fertilization because of its protruding embryo sac. However, information on the
genomes and chromosomes of this species is limited. We determined the genome sizes of T. fournieri Linden and T. baillonii Godefr as 1.71 pg × 108 bp and 1.67 × 108 bp, respectively. The small genome size of these species suggests their superiority as the targets for molecular cloning
studies. Furthermore, karyotypes of T. fournieri and T. baillonii were determined using FISH probed with 5S rDNA, 45S rDNA and species-specific centromere repetitive sequences. Although the
two species have similar genome size, number of chromosomes, centromere repeats and 5S rDNA loci were varied. Observation
of meiosis in the F1 hybrid revealed that all chromosomes except one of T. fournieri paired well with the chromosomes of T. baillonii throughout the entire length of the chromosomes including species-specific centromeric regions. One exceptional chromosome
of T. fournieri behaved as a univalent and was not always required for gametogenesis. The present results provide the basis for the molecular
genetics in Torenia. 相似文献
3.
We investigated chromosome evolution in Nemesia using fluorescent in-situ hybridization (FISH) to identify the locations of 5S and 45S (18–26S) ribosomal genes. Although there was conservation between
Nemesia species in chromosome number, size and centromere position, there was large variation in both number and position of ribosomal
genes in different Nemesia species (21 different arrangements of 45S and 5S rRNA genes were observed in the 29 Nemesia taxa studied). Nemesia species contained between one and three pairs of 5S arrays and between two and four pairs of 45S arrays. These were either
sub-terminally or interstitially located and 45S and 5S arrays were often located on the same chromosome pair. Comparison
of the positions of rDNA arrays with meiotic chromosome behaviour in interspecific hybrids of Nemesia suggests that some of the changes in the positions of rDNA have not affected the surrounding chromosome regions, indicating
that rDNA has changed position by transposition. Chromosome evolution is frequently thought to occur via structural rearrangements
such as inversions and translocations. We suggest that, in Nemesia, transposition of rDNA genes may be equally if not more important in chromosome evolution. 相似文献
4.
Population variation in the A chromosome distribution of satellite DNA and ribosomal DNA in the grasshopper Eyprepocnemis plorans 总被引:2,自引:0,他引:2
J. Cabrero F. Perfectti R. Gómez J. P. M. Camacho M. D. López-León 《Chromosome research》2003,11(4):375-381
The double FISH analysis of two repetitive DNAs (a satellite DNA and ribosomal DNA) in 12 natural populations of the grasshopper Eyprepocnemis plorans collected at the south (Granada and Málaga provinces) and south-east (Albacete and Murcia provinces) of the Iberian Peninsula has shown their widespread presence throughout the whole genome as well as extensive variation among populations. Both DNAs are found in most A chromosomes. Regularly, both DNAs occurred in the S11 and X chromosomes, rDNA in the S10 and satDNA in the L2 and M3. No correlation was found between the number of satDNA and rDNA clusters in the A genomes of the 12 populations analysed, and both figures were independent of the presence of B chromosomes. The genomic distribution of both DNAs showed no association with the geographical localization of the populations analysed. Finally, we provide evidence that the supernumerary chromosome segment proximally located on the S11 chromosome is, in most cases, the result of satDNA amplification but, in some cases, it might also derive from amplification of both satDNA and rDNA. 相似文献
5.
Chromosomal Location and Nucleotide Sequences of 5S Ribosomal DNA of Two Cyprinid Species (Osteichthyes, Pisces) 总被引:3,自引:0,他引:3
Junya Inafuku Mika Nabeyama Yutaka Kikuma Junji Saitoh Souichirou Kubota Sei-ichi Kohno 《Chromosome research》2000,8(3):193-199
5S ribosomal DNAs (rDNAs) from two cyprinid species, Acheilognathus tabira subsp. 1 and Cyprinus carpio, were isolated and sequenced. Tandemly arranged rDNAs were 179 bp in A. tabira and 204 bp in C. carpio. The non-transcribed spacer region elucidates the size difference of 5S rDNA between the two species. Fluorescence in-situ hybridization (FISH) localized 5S rDNAs to the short arms of two pairs of chromosomes in A. tabira and two to four pairs in C. carpio. Subsequent analysis demonstrated NORs in one pair of chromosomes in both species. Both the NOR and 5S rDNA are carried by
a chromosome pair in A. tabira, but they are located on different chromosomes separately in C. carpio. Karyotype evolution by tetraploidy seems complex in cyprinid species.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
Some of the largest B chromosomes so far discovered in vertebrates are present in the cyprinid fish Alburnus alburnus. Previous cytogenetic analyses revealed a diploid chromosome number of 2n = 50. In addition, in some individuals one or two
unusually large B chromosomes are present. Two morphologically different types of B chromosomes were observed. The frequency
of animals bearing a supernumerary chromosome was found to vary considerably between different populations. A more detailed
analysis of the A and B chromosomes of A. alburnus by conventional banding techniques, as well as fluorescence in-situ hybridization (FISH) with the telomeric DNA repeats (GGGTTA)7/(TAACCC)7, 18S + 28S rDNA and 5S rDNA were performed in the present study. Furthermore, a B chromosome-specific DNA probe obtained
by amplified length polymorphism (AFLP) was hybridized on metaphases of A. alburnus carrying supernumerary B chromosomes. The banding analyses showed that the B chromosomes are completely heterochromatic,
consist of GC-rich DNA sequences, replicate their DNA in the very late S-phase of the cell cycle and are composed mainly of
a specific retrotransposable DNA element. Finally, blood probes from A. alburnus were collected for DNA-flow cytometric measurements. It could be shown that the huge supernumerary chromosomes represent
nearly 10% of the total genome size of A. alburnus. 相似文献
7.
An XX/XY Sex Chromosome System in a Fish Species, Hoplias malabaricus, with a Polymorphic NOR-Bearing X Chromosome 总被引:3,自引:0,他引:3
Cytogenetic studies were carried out in the fish, Hoplias malabaricus, from the Parque Florestal do Rio Doce (Brazil). This population is characterized by 2n = 42 chromosomes for both males and females and an XX/XY sex chromosome system, confirmed through several banding methods. Females show 24 metacentric, 16 submetacentric and 2 subtelocentric chromosomes. Males show 24 metacentric, 17 submetacentric and 1 subtelocentric chromosomes. While the X chromosome is easily recognized (the only subtelocentric element), the Y chromosome is somewhat difficult to identify but appears to correspond to the smallest submetacentric in the male karyotype. In-situ hybridization with an 18S rDNA probe showed 10 well-labeled chromosomes, including the X chromosome. The 5S rDNA is interstitially located in a single metacentric pair independent of the 18S rDNA sites. The NOR on the X chromosome is always active and occurs adjacent to a heterochromatic distal segment on the long arm. Variations in size of the NORs and/or heterochromatic segment correspond to a polymorphic size condition observed in the X chromosome. The present results confirm the XX/XY sex chromosome system in the population analyzed as well as a new cytotype in the Hoplias malabaricus group. 相似文献
8.
Triploid origin of the gibel carp as revealed by 5S rDNA localization and chromosome painting 总被引:2,自引:0,他引:2
5S ribosomal DNA (rDNA) was isolated and sequenced from the gibel carp Carassius auratus gibelio with 162 chromosomes and crucian carp Carassius auratus with 100 chromosomes, and fluorescent probes for chromosome localization were prepared to ascertain the ploidy origin and
evolutionary relationship between the two species. Using fluorescence in-situ hybridization (FISH), major 5S rDNA signals were localized to the short arms of three subtelocentric chromosomes in the gibel
carp and to the short arms of two subtelocentrics in the crucian carp. In addition, some minor signals were detected on other
chromosomes of both species. Simultaneously, six chromosomes were microdissected from the gibel carp metaphase spreads using
glass needles, and the isolated chromosomes were amplified in vitro by degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR). Significantly, when the DOP-PCR-generated probes
prepared from each single chromosome were hybridized, three same-sized chromosomes were painted in each gibel carp metaphase,
whereas only two painted chromosomes were observed in each crucian carp metaphase spread. The data indicate that gibel carp
is of triploid origin in comparison with diploid crucian carp. 相似文献
9.
Yoshinobu Uno Chizuko Nishida Shin Yoshimoto Michihiko Ito Yuki Oshima Satoshi Yokoyama Masahisa Nakamura Yoichi Matsuda 《Chromosome research》2008,16(7):999-1011
Amphibians employ genetic sex determination systems with male and female heterogamety. The ancestral state of sex determination
in amphibians has been suggested to be female heterogamety; however, the origins of the sex chromosomes and the sex-determining
genes are still unknown. In Xenopus laevis, chromosome 3 with a candidate for the sex- (ovary-) determining gene (DM-W) was recently identified as the W sex chromosome. This study conducted comparative genomic hybridization for X. laevis and Xenopus tropicalis and FISH mapping of eight sexual differentiation genes for X. laevis, X. tropicalis, and Rana rugosa. Three sex-linked genes of R. rugosa—AR,
SF-1/Ad4BP, and Sox3—are all localized to chromosome 10 of X. tropicalis, whereas AR and SF-1/Ad4BP are mapped to chromosome 14 and Sox3 to chromosome 11 in X. laevis. These results suggest that the W sex chromosome was independently acquired in the lineage of X. laevis, and the origins of the ZW sex chromosomes are different between X. laevis and R. rugosa. Cyp17, Cyp19, Dmrt1, Sox9, and WT1 were localized to autosomes in X. laevis and R. rugosa, suggesting that these five genes probably are not candidates for the sex-determining genes in the two anuran species. 相似文献
10.
Eduardo A. Moscone Rosabelle Samuel Trude Schwarzacher Dieter Schweizer Andrea Pedrosa-Harand 《Chromosome research》2007,15(7):931-943
The genus Cephalanthera is an excellent plant group for karyotype evolution studies because it exhibits a dysploid series and bimodal karyotypes.
With the aim of understanding their chromosomal and phylogenetic relationships, rRNA genes and the Arabidopsis-type telomeric sequence were mapped by fluorescence in-situ hybridization (FISH), and the rDNA intergenic spacer (ITS) was sequenced for the first time in three European species: C. longifolia (2n = 4x = 32), C. damasonium (2n = 4x = 36) and C. rubra (2n = 4x = 44). One 45S and three 5S rDNA sites are observed in C. longifolia, one 45S and two 5S sites in C. damasonium, and two 45S and one 5S site in C. rubra. Telomeric signals were observed at every chromosome end in all three species and C. damasonium also displays interstitial signals on three chromosome pairs. In agreement with chromosome data, molecular analyses support
C. longifolia and C. damasonium as closely related taxa, while C. rubra stands apart. Possible pathways of karyotype evolution are discussed in reference to a previous hypothesis. The results indicate
that complex chromosomal rearrangements, possibly involving Robertsonian fusions and fissions, loss of telomeric repeats,
gain or loss of rDNA sites and other heterochromatic sequences and inversions, may have contributed to generating the present-day
karyotypes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
Masaki Fujisawa Shigeki Nakayama Tomohisa Nishio Mariko Fujishita Kiwako Hayashi Kimitsune Ishizaki Masataka Kajikawa Katsuyuki T. Yamato Hideya Fukuzawa Kanji Ohyama 《Chromosome research》2003,11(7):695-703
In the haploid dioecious liverwort, Marchantia polymorpha, the X chromosome, but not the Y, carries a cluster of ribosomal RNA genes (rDNAs). Here we show that sequences of 5S, 17S,
5.8S and 26S rDNAs are highly conserved (>99% identity) between the X chromosomal and autosomal rDNA repeat units, but the
intergenic spacer sequences differ considerably. The most prominent difference is the presence of a 615-bp DNA fragment in
the intergenic spacer, X615, which has accumulated predominantly in the rDNA cluster of the X chromosome. These observations
suggest that the rDNA repeat unit on the X chromosome evolved independently of that on autosomes, incorporating sex chromosome-specific
sequences.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
H. M. Thomas J. A. Harper M. R. Meredith W. G. Morgan I. D. Thomas E. Timms I. P. King 《Chromosome research》1996,4(7):486-490
The position of the 18S-5.8S-26S and 5S rRNA genes have been physically mapped on the chromosomes of sevenLolium taxa. 18S-5.8S-26S sites were seen on two pairs of chromosomes in the inbreeding taxa. In the outbreeding taxa six sites were found in theL. multiflorum, seven inL. perenne and nine inL. rigidum var.rigidum. Two 5S sites were found in each of the taxa. In the inbreeders, the 5S sites were found adjacent to the 18S-5.8S-26S sites on chromosome 2. InL. multiflorum andL. perenne the 5S sites were on the short arm of chromosome 3. However, inL. rigidum var.rigidum the 5S rDNA site was found in either of the two positions.accepted by J.S. (Pat) Heslop-Harrison 相似文献
13.
Marta Gromicho Jean-Pierre Coutanceau Catherine Ozouf-Costaz Maria João Collares-Pereira 《Chromosome research》2006,14(3):297-306
The diploid–polyploid Squalius alburnoides complex resulted from interspecific hybridization. The chromosomal mapping of 28S and 5S ribosomal genes and of (TTAGGG)n telomeric repeats was performed on specimens from the complex and from the sympatric bisexual species S. pyrenaicus (the complex maternal ancestor) as part of an investigation of the evolutionary relationships between genomic constitutions
and the consequences of the ongoing polyploidization process in terms of chromosome reshaping. Contrasting results were obtained.
While results with 5S rDNA and telomeric probes gave an impression of genomic stability, the variability detected with 28S
rDNA probe suggested quite the opposite. The 5S rDNA probe mapped constantly to three chromosomes per haploid genome with
apparently conserved locations in morphologically similar chromosomes; conversely, prominent intra- and inter-individual variations
of 28S rDNA and of syntenic sites with 5S rDNA were detected with regard to number, size and location. Hypotheses for the
causes of such polymorphisms are discussed. The terminal position of most 28S rDNA sites and the absence of detectable interstitial
telomeric sequences suggest a mechanism that does not involve major chromosomal rearrangements. These fishes share similar
patterns for the studied cytogenetic markers which may be taken as evidence of an apparent stability that may be hiding extensive
and subtle genome variations that are possibly related to an ongoing evolutionary process of genome tetraploidization and
speciation. 相似文献
14.
There are only a few reports on the chromosomal location of DNA sequences in bivalve species, none of them using meiotic chromosomes. Mitotic chromosomes of the clam Dosinia exoleta were analysed by means of Giemsa, silver and fluorochrome staining and fluorescent in situ hybridization (FISH) with 18S + 28S rDNA and telomeric probes. A technique for surface spreading of synaptonemal complexes (SCs) of Dosinia exoleta was developed for the first time in a bivalve species. Silver and DAPI/PI staining and SC-FISH were also applied to the study of the meiotic chromosomes of this clam. The diploid chromosome number in this species is 38 and the karyotype is composed of 11 pairs of metacentric and eight pairs of submetacentric chromosomes. 18S + 28S rDNA clusters map to the subtelomeric region of the short arm of one metacentric chromosome pair whereas telomeric signals appear at both ends of every chromosome. 相似文献
15.
Ana Paula de Moraes Walter dos Santos Soares Filho Marcelo Guerra 《Chromosome research》2007,15(1):115-121
Grapefruit is a group of citrus of recent origin, probably resulting from a cross between pummelo and sweet-orange. Aiming
to investigate this putative origin and the genetic variability among grapefruit cultivars, the karyotype of six grapefruits,
two pummelos, and one tangelo cultivar (grapefruit × tangerine) were analyzed using sequential CMA/DAPI double staining and
FISH with rDNA probes. The karyotypes of grapefruit ‘Duncan’ and ‘Foster’ differ from those of ‘Flame’, ‘Henderson’, ‘Marsh’
and ‘Rio Red’. The former have two chromosomes with a single CMA+ band in both terminal regions (C type chromosome) and six chromosomes with only one CMA+ terminal band (D type), whereas the latter have three C and five D type chromosomes. All accessions investigated exhibited
two chromosomes with 5S rDNA but a variable number of 45S rDNA. The two former grapefruits displayed four 45S rDNA sites,
whereas the remaining grapefruit cultivars had five. The two pummelos showed identical karyotypes, homozygous for CMA+ bands and their four rDNA sites. From each pummelo chromosome pair one chromosome seems to be present in grapefruit karyotypes.
The different grapefruit karyotypes might result from independent crosses between pummelos of different karyotypic constitution
and sweet-oranges. The chromosome markers found in the tangelo ‘Orlando’ and the position of their two 45S rDNA confirm the
grapefruit ‘Duncan’ and the tangerine ‘Dancy’ as their parents. 相似文献
16.
Nieves Cuñado Rafael Navajas-Pérez Roberto de la Herrán Carmelo Ruiz Rejón Manuel Ruiz Rejón Juan Luis Santos Manuel A. Garrido-Ramos 《Chromosome research》2007,15(7):825-833
The structural features and evolutionary state of the sex chromosomes of the XX/XY species of Rumex are unknown. Here, we report a study of the meiotic behaviour of the XY bivalent in Rumex acetosella and R. suffruticosus, a new species which we describe cytogenetically for the first time in this paper, and also that of the XY1Y2 trivalent of R. acetosa by both conventional cytogenetic techniques and analysis of synaptonemal complex formation. Fluorescent in situ hybridization with satellite DNA and rDNA sequences as probes was used to analyse the degree of cytogenetic differentiation between the X and Y chromosomes in order to depict their evolutionary stage in the three species. Contrasting with the advanced state of genetic differentiation between the X and the Y chromosomes in R. acetosa, we have found that R. acetosella and R. suffruticosus represent an early stage of genetic differentiation between sex chromosomes. Our findings further demonstrate the usefulness of the genus Rumex as a model for analysing the evolution of sex chromosomes in plants, since within this genus it is now possible to study the different levels of genetic differentiation between the sex chromosomes and to analyse their evolutionary history from their origin. 相似文献
17.
Fluorescence in-situ hybridization was used to construct a comparative chromosome map between the laboratory mouse, Mus musculus and the African four-striped mouse, Rhabdomys pumilio. A high degree of homology between the species was detected using both FISH and G-banding. Ten mouse chromosomes (2–4, 7, 14–16, 18, 19 and the X) were retained as chromosomal arms or intact chromosome blocks. Six mouse chromosome painting probes that correspond to mouse autosomes 5, 6, 8, 11, 12 and 13, produced double signals; the remaining four painting probes (1, 9, 10 and 17) hybridized to three or more R. pumilio chromosomes respectively. In total, the 20 mouse chromosome paints revealed 40 segments of conserved synteny in the R. pumilio genome. Most of the mouse chromosomes that produced single signals in R. pumilio have previously been shown to be conserved in the Black and Norwegian rats and the Chinese hamster. Eight contiguous segment associations appear to be R. pumilio specific, two were shared by R. pumilio and the Black and Norwegian rats, but to the exclusion of the Chinese hamster. Our data suggest that mouse chromosomes 1, 10, and 17 have undergone extensive rearrangements during genome evolution in the murids and may be useful markers for enhancing our understanding of the mode and tempo of chromosome evolution in rodents. 相似文献
18.
Genomic in-situ hybridization (GISH) was applied to study the behaviour of addition chromosomes in first and second backcross (BC) progenies
of hybrids between Brassica napus ssp. napus L. (AACC, 2n = 38) and Sinapis alba L. (SS, 2n = 24) produced by electrofusion. With GISH using genomic DNA of S. alba was used as probe it was possible to clearly distinguish both of the parental genomes and effectively monitor the fate of
S. alba chromosomes in the BC1 and BC2 progenies. GISH analysis confirmed the sesquidiploid genome composition (AACCS) of the BC1 progenies, which contained 38 chromosomes from B. napus and 12 chromosomes from S. alba. Genome painting in the pollen mother cells (PMCs) of the BC1 plants revealed intergenomic association between B. napus and S. alba chromosomes, whereby a maximum of 4 trivalents between AC and S chromosomes were identified at metaphase I. In the BC2 progenies, aneuploids with different numbers of additional chromosomes from S. alba, ranging from 1 to 7, were confirmed. Three putative monosomic alien addition lines were characterized, and the results are
discussed with respect to the potential for intergenomic chromosome recombination. 相似文献
19.
María Teruel Josefa Cabrero Eugenia E. Montiel Manuel J. Acosta Antonio Sánchez Juan Pedro M. Camacho 《Chromosome research》2009,17(1):11-18
Acquisition of knowledge of the nature and DNA content of B chromosomes has been triggered by a collection of molecular techniques,
one of which, microdissection, has provided interesting results in a number of B chromosome systems. Here we provide the first
data on the molecular composition of B chromosomes in Locusta migratoria, after microdissection of the B and X chromosomes, DNA amplification by one (B) or two (X) different methods, and chromosome
painting. The results showed that B chromosomes share at least two types of repetitive DNA sequences with the A chromosomes,
suggesting that Bs in this species most likely arose intraspecifically. One of these repetitive DNAs is located on the heterochromatic
distal half of the B chromosome and in the pericentromeric regions of about half of the A chromosomes, including the X. The
other type of repetitive DNA is located interspersedly over the non-centromeric euchromatic regions of all A chromosomes and
in an interstitial part of the proximal euchromatic half of the B chromosome. Chromosome painting, however, did not provide
results sufficiently reliable to determine, in this species, which A chromosome gave rise to the B; this might be done by
detailed analysis of the microdissected DNA sequences 相似文献
20.
P. Hamon S. Siljak-Yakovlev S. Srisuwan O. Robin V. Poncet S. Hamon A. de Kochko 《Chromosome research》2009,17(3):291-304
The chromosome organization among 15 wild diploid Coffea species and cultivated tetraploid C. arabica was determined by fluorochrome banding (CMA, DAPI) and double fluorescence in-situ hybridization (FISH) of 5S and 18S rDNA
achieved on the same chromosome plates. Two to five chromosome pairs (plus one putative chromosome B) are marked. Overall,
there are two SAT-chromosome pairs for East African species and one for the Malagasy and the West and Central African species.
18S rDNA loci are telomeric and strongly marked the SAT-chromosome pairs. Generally, only one pericentromeric 5S rDNA locus
characterized East African species, while an additional minor locus co-localized with the 18S rDNA-SAT locus for the Malagasy
species and West and Central African species. A combination of rDNA FISH plus CMA and DAPI banding patterns enables identification
of almost all the species, even those for which the genetic or botanical status is still being discussed. C. arabica clearly appears to be an allotetraploid species, including one genome from East Africa and one from West and Central Africa.
However, since the minor 5S rDNA-SAT locus present in West/Central African genomes is not detected, two evolutionary hypotheses
could be put forward for C. arabica. Considering only the diploid species, global trends are obvious in rDNA signal patterns, genome size variations, and geographic
distribution of the species, but there are no clear evolutionary trends. However, complex interactions between these factors
and environmental growing conditions exist, which have resulted in loss and gain of rDNA loci and probably also in copy repeat
number variations in each rDNA family. 相似文献