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1.
Karyotype and other chromosomal markers of Characidium cf. gomesi were analyzed using conventional (Giemsa-staining, Ag-NOR and C-banding) and molecular (Fluorescent in situ hybridization
(FISH) with 18S and 5S rDNA biotinylated probes) techniques. Both sexes had invariably diploid chromosome number 2n = 50 while
karyotypes of males and females differed. That of male consisted of 32 metacentric + 18 submetacentric chromosomes and that
of female consisted 31 metacentric + 18 submetacentric + 1 subtelocentric chromosomes. The Z chromosome was medium-sized metacentric,
while W was highly heterochromatinized subtelocentric element. NORs as revealed by Ag-staining were situated at 2–7 telomeric
regions while FISH with 18S probes showed consistently 10 signals at telomeric regions. FISH with 5S rDNA probe showed constantly
signals at one metacentric pair. Distribution of centromeric heterochromatin was mostly in all chromosome pairs, besides some
telomeric sites. The common origin of the sex chromosome system of ZZ/ZW type in the karyotypes of other representatives of
the genus analyzed so far might be hypothesized based on biogeography and partial phylogeny of the group. 相似文献
2.
Chromosomes of Triportheus nematurus, a fish species from family Characidae, were analyzed in order to establish the conventional karyotype, location of C-band
positive heterochromatin, Ag-NORs, GC- and AT-rich sites, and mapping of 18S and 5S rDNA with fluorescence in situ hybridization
(FISH). The diploid number found was 2n = 52 chromosomes in both males and females. However, the females presented a pair
of differentiated heteromorphic chromosomes, characterizing a ZZ/ZW sex chromosome system. The Z chromosome was metacentric
and the largest one in the karyotype, bearing C-positive heterochromatin at pericentromeric and telomeric regions. The W chromosome
was middle-sized submetacentric, appearing mostly heterochromatic after C-banding and presenting heterogeneous heterochromatin
composed of GC- and AT-rich regions revealed by fluorochrome staining. Ag-NORs were also GC-rich and surrounded by heterochromatic
regions, being located at the secondary constriction on the short arms of the second chromosome pair, in agreement with 18S
rDNA sites detected with FISH. The 18S and 5S rDNA were aligned in tandem, representing an uncommon situation in fishes. The
results obtained reinforce the basal condition of the ZZ/ZW sex system in the genus Triportheus, probably arisen prior to speciation in the group. 相似文献
3.
Karyotypic and cytogenetic characteristics of catfish Harttia carvalhoi (Paraíba do Sul River basin, S?o Paulo State, Brazil) were investigated using differential staining techniques (C-banding, Ag-staining) and fluorescent in situ hybridization (FISH) with 18S and 5S rDNA probes. The diploid chromosome number of females was 2n = 52 and their karyotype was composed of nine pairs of metacentric, nine pairs of submetacentric, four pairs of subtelocentric and four pairs of acrocentric chromosomes. The diploid chromosome number of males was invariably 2n = 53 and their karyotype consisted of one large unpaired metacentric, eight pairs of metacentric, nine pairs of submetacentric, four pairs of subtelocentric, four pairs of acrocentric plus two middle-sized acrocentric chromosomes. The differences between female and male karyotypes indicated the presence of a sex chromosome system of XX/XY1Y2 type, where the X is the largest metacentric and Y1 and Y2 are the two additional middle-sized acrocentric chromosomes of the male karyotype. The major rDNA sites as revealed by FISH with an 18S rDNA probe were located in the pericentromeric region of the largest pair of acrocentric chromosomes. FISH with a 5S rDNA probe revealed two sites: an interstitial site located in the largest pair of acrocentric chromosomes, and a pericentromeric site in a smaller metacentric pair of chromosomes. Translocations or centric fusions in the ancestral 2n = 54 karyotype is hypothesized for the origin of such multiple sex chromosome systems where females are fixed translocation homozygotes whereas males are fixed translocation heterozygotes. The available cytogenetic data for representatives of the genus Harttia examined so far indicate large kayotype diversity. 相似文献
4.
Karyotype and cytogenetic markers of Oligosarcus hepsetus from two Brazilian locations in the Paraíba do Sul River Basin (Brazil) were investigated using differential staining techniques (C-banding, silver (Ag)- and chromomycin A3 (CMA3)-staining) and fluorescent in situ hybridization (FISH) using 18 S rDNA and 5 S rDNA probes. The diploid chromosome number was invariably 2n = 50 with 3 pairs of metacentric, 5 pairs of submetacentric, 8 pairs of subtelocentric and 9 pairs of acrocentric chromosomes. No heteromorphic sex chromosomes were observed. The nucleolar organizer regions (NORs) were detected in the short arms of the largest acrocentric pair using Ag-, CMA3- stainings and FISH with 18 S rDNA probe, the latter showing also positive labeling in the short arms of a small acrocentric pair, not visualized by the former methods. FISH with 5 S rDNA probe showed positive labeling in the two chromosome pairs. While the CMA3-staining exhibited GC-rich heterochromatin segments in two pairs of chromosomes, including those coincided with Ag-NORs, the DAPI staining did not reveal any signal, indicating the absence of AT-rich heterochromatin. FISH with an As-51 satellite DNA probe derived from the closely related Astyanax scabripinnis did not reveal any positive signal, demonstrating the absence of this class of DNA in the genome of the specimens under study. 相似文献
5.
6.
Karyotypic and cytogenetic characteristics of Vimba vimba and V. elongata were investigated using differential staining techniques (sequential C-banding, Ag- and CMA3-staining) and fluorescent in situ hybridization (FISH) with 28S rDNA probe. The diploid chromosome number in both species was 2n = 50 with 8 pairs of metacentrics, 14 pairs of submetacentrics to subtelocentrics and 3 pairs of subtelo- to acrocentrics. The largest chromosome pair of the complements was characteristically subtelo- to acrocentric. The nucleolar organizer regions (NORs) in both species were detected in the telomeres of a single, middle-sized subtelocentric chromosome pair, a pattern common in a number of other Leuciscinae. FISH with rDNA probe produced consistently positive hybridization signals detected in the same regions indicated by Ag-staining and CMA3-fluorescence. The distribution of C-positive heterochromatin was identical in both species, including a conspicuous size polymorphism of heterochromatic blocks in the largest metacentric and subtelo- to acrocentric chromosomal pairs. No heteromorphic sex chromosomes were detected. A single analyzed individual of V. melanops possessed the same karyotype and NOR phenotype as V. vimba and V. elongata. The apparent karyotype homogeneity and chromosomal characteristics of ribosomal DNA in all three species of the genus Vimba is consistent to that found in most other representatives of the European leuciscine cyprinid fishes. 相似文献
7.
Polypteridae is a family of archaic freshwater African fish that constitute an interesting subject for the study of the karyological evolution in vertebrates, on account of their primitive morphological characters and peculiar relationships with lower Osteichthyans. In this paper, a cytogenetic analysis on twenty specimens of both sexes of Polypterus ornatipinnis the ornate "bichir", coming from the Congo River basin, was performed by using both classical and molecular techniques. The karyotypic formula (2n=36; FN=72) was composed of 26 M+10 SM. The Alu I banding, performed to characterize heterochromatin in this species, was mainly centromeric. Both the chromosome location of the ribosomal 5S and 18S rRNA genes were examined by using Ag-NOR, classical C-banding, CMA(3) staining and FISH. CMA(3) marked all centromerical regions and showed the presence of two GC rich regions on the p arm of the chromosome pair n°1 and on the q arm of the pair n°14. Staining with Ag-NOR marked the only telomeric region of the chromosome n°1 p arm. After PCR, the 5S rDNA in this species was cloned, sequenced and analyzed. In the 665bp 5S rDNA sequence of P.ornatipinnis, a conserved 120bp gene region for the 5S rDNA was identified, followed by a non-transcribed variable spacer (NTS) which included simple repeats, microsatellites and a fragment of a non-LTR retrotransposon R-TEX. FISH with 5S rDNA marked the subtelomeric region of the q arm of the chromosome pair n°14, previously marked by CMA(3). FISH with 18S rDNA marked the telomeric region of the p arm of the pair n°1, previously marked both by Ag-NOR and CMA(3). The (GATA)(7) repeats marked the telomeric regions of all chromosome pairs, with the exclusion of the n°1, n°3 and n°14; hybridization with telomeric probes (TTAGGG)(n) showed signals at the end of all chromosomes. Karyotype evolution in Polypterus genus was finally discussed, including the new data obtained. 相似文献
8.
E. Bellafronte M. R. Vicari R. F. Artoni V. P. Margarido O. Moreira‐Filho 《Journal of fish biology》2009,75(9):2313-2325
Conventional and molecular chromosomal analyses were carried out on three populations of Apareiodon ibitiensis sampled from the hydrographic basins of the São Francisco River and Upper Paraná River (Brazil). The results reveal a conserved diploid number (2n = 54 chromosomes), a karyotype formula consisting of 50 m‐sm + 4st and a ZZ/ZW sex chromosome system that has not been previously identified for the species. C‐banding analysis with propidium iodide staining revealed centromeric and terminal bands located in the chromosomes of the specimens from the three populations and allowed the identification of heteromorphism of heterochromatin regions in the Z and W chromosomes. The number of 18S sites located through fluorescent in situ hybridization (FISH) varied between the populations of the São Francisco and Upper Paraná Rivers. The location of 5S rDNA sites proved comparable in one pair of metacentric chromosomes. Thus, the present study proposes a ZZ/ZW sex chromosome system for A. ibitiensis among the Parodontidae, and a hypothesis is presented regarding possible W chromosome differentiation stages in this species through DNA accumulation, showing geographical variations for this characteristic, possibly as a consequence of geographical reproductive isolation. 相似文献
9.
Takahashi C 《Journal of plant research》2003,116(4):331-336
The chromosomal locations of the 18S-5.8S-26S rDNA and 5S rDNA sequences were examined in four cytotypes of Ranunculus silerifolius (the Matsuyama, Mugi, Otaru, and Karatsu types) using fluorescence in situ hybridization (FISH). Using the 18S-5.8S-26S rDNA probe, one pair of probe hybridization sites was detected by FISH in the interstitial region corresponding to the secondary constriction on the short arm of a satellite chromosome (chromosome pair 6) in all four karyotypes. FISH using 5S rDNA identified one pair of sites. The 5S rDNA locus was on different chromosomes in the four karyotypes: in the interstitial region of the short arm of the largest metacentric chromosome (chromosome pair 1) in the Matsuyama type, in the interstitial region of the short arm of the subtelocentric chromosome (pair 2) in the Mugi and Otaru types, and in the interstitial region of the short arm of the metacentric chromosome (pair 2) in the Karatsu type. This physical mapping of the 5S rDNA provides valuable information about karyotype evolution in R. silerifolius. Possible mechanisms of chromosome evolution are discussed. 相似文献
10.
The karyotype of Halobatrachus didactylus presents 46 chromosomes, composed of eight metacentric, 18 submetacentric, four subtelocentric, and 16 acrocentric chromosomes.
The results of FISH showed that the major ribosomal genes were located in the terminal position of the short arm of a large
submetacentric chromosome. They also showed a high variation in the hybridization signals. The products of amplification of
5S rDNA produced bands of about 420 pb. The PCR labeled products showed hybridization signals in the subcentromeric position
of the long arm of a submetacentric chromosome of medium size. Double-color FISH indicated that the two ribosomal families
are not co-located since they hybridizated in different chromosomal pairs. Telomeres of all the chromosomes hybridized with
the (TTAGGG)
n
probe. The GATA probe displayed a strong signal in the long arm of a submetacentric chromosome of medium size, in the subcentromeric
position. The double-color FISH showed that the microsatellite GATA and the 5S rDNA gene are located in different chromosomal
pairs. The majority presence of GATA probes in one pair of chromosomes is unusual and considering its distribution through
different taxa it could be due to evolutionary mechanisms of heterochromatine accumulation, leading to the formation of differentiated
sex chromosomes. 相似文献
11.
Physical mapping of the 5S ribosomal RNA genes in Arabidopsis thaliana by multi-color fluorescence in situ hybridization with cosmid clones 总被引:4,自引:0,他引:4
Minoru Murata J.S. Heslop-Harrison Fusao Motoyoshi 《The Plant journal : for cell and molecular biology》1997,12(1):31-37
The 5S ribosomal RNA genes were mapped to mitotic chromosomes of Arabidopsis thaliana by fluorescence in situ hybridization (FISH). In the ecotype Landsberg erecta, hybridization signals appeared on three pairs of chromosomes, two of which were metacentric and the other acrocentric. Hybridization signals on one pair of metacentric chromosomes were much stronger than those on the acrocentric and the other pair of metacentric chromosomes, probably reflecting the number of copies of the genes on the chromosomes. Other ecotypes, Columbia and Wassilewskija, had similar chromosomal distribution of the genes, but the hybridization signals on one pair of metacentric chromosomes were very weak, and detectable only in chromosomes prepared from young flower buds. The chromosomes and arms carrying the 5S rDNA were identified by multi-color FISH with cosmid clones and a centromeric 180 bp repeat as co-probes. The metacentric chromosome 5 and its L arm carries the largest cluster of the genes, and the short arm of acrocentric chromosome 4 carries a small cluster in all three ecotypes. Chromosome 3 had another small cluster of 5S rRNA genes on its L arm. Chromosomes 1 and 2 had no 5S rDNA cluster, but they are morphologically distinguishable; chromosome 1 is metacentric and 2 acrocentric. Using the 5S rDNA as a probe, therefore, all chromosomes of A. thaliana could be identified by FISH. Chromosome 1 is large and metacentric; chromosome 2 is acrocentric carrying 18S-5.8S-25S rDNA clusters on its short arm; chromosome 3 is metacentric carrying a small cluster of 5S rDNA genes on its L arm; chromosome 4 is acrocentric carrying both 18S-5.8S-25S and 5S rDNAs on its short (L) arm; and chromosome 5 is metacentric carrying a large cluster of 5S rDNA on its L arm. 相似文献
12.
A comparative molecular cytogenetic analysis was performed on three species of the genus Leuciscus viz. ide L. idus, chub L. cephalus and dace L. leuciscus distributed in Poland, using C-, Ag- and chromomycin A3 (CMA3)-stainings and fluorescence in situ hybridization (FISH) with 5.8S + 28S rDNA as a probe. Although the three species examined
shared 2n = 50 chromosomes and the largest acrocentric chromosome pair in the complement, they were characterized with karyotypic
differences in terms of the number of uni- and biarmed chromosomes and the localization of nucleolar organizer regions (NORs)
revealed by Ag-staining and FISH. L. idus and L. cephalus showed the rDNA sites on the long arms of one submetacentric (SM) chromosome pair and on the short arms of one subtelocentric
(ST) chromosome pair, respectively. These NORs were CMA3-positive, GC-rich and C-positive heterochromatic sites in both species. Such chromosome banding features were also true for
four NORs localizing on one of each SM and ST pair in L. leuciscus, but considerable numerical NOR polymorphism became apparent with Ag-staining and FISH due to a different combination of
these NOR-bearing SMs and STs in this dace. The present results indicate that the molecular cytogenetic analysis applied herein
may become useful to elucidate the karyotype evolution and phylogenetic relationships among the species in the genus Leuciscus and other related groups. 相似文献
13.
The present paper reports the Results of rice field eel (Monopterus albus Zuiew) chromosomal analysis by Ag-staining techniques, FISH and ISH with 18S rDNA. Both the Ag-NORs and the hybridization signals were observed on the pericentromeric region of chromosome pairs 3 and 7. The Ag-NORs and the hybridization signals on homologous chromosomes 3 and 7 were corresponding to each other. And rDNA genes were mapped to bivalents 3q12-q24 and 7q14-q26. No heteromorphic sex chromosome pair was identified. The Results obtained were discussed with respect to the feature of Ag-NORs and the position of rDNA genes on chromosome pairs 3 and 7. 相似文献
14.
O. Schrader H. Budahn R. Ahne 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(5):665-669
Different ribosomal RNA (5S and 25S) genes were investigated simultaneously by fluorescence in situ hybridization (FISH) in
Sinapis alba, Raphanus sativus and Brassica napus. The chromosomes of S. alba carried four 5S and six 25S gene sites, and those of R. sativus four sites of each gene, respectively. These two species have one chromosome pair with both rDNA genes; the two are closely
located on a short arm of S. alba, while in R. sativus one is distal on the short arm (5S) and the other more proximal on the long arm (25S). In B. napus we have confirmed 12sites of 25S rDNA. The detection of 5S rDNA genes revealed 14 signals on 12 chromosomes. Of these, six
chromosomes had signals for both rDNA genes. The FISH with 5S rDNA probes detected two sites closely adjacent in four chromosomes
of B napus. These results are discussed in relation to a probable homoeologous chromosome pair in B. oleracea.
Received: 20 July 1999 / Accepted: 8 October 1999 相似文献
15.
16.
Vishwamitra Singh Baisvar Basdeo Kushwaha Ravindra Kumar Murali Sanjeev Kumar Manmohan Pandey Mahender Singh 《Zeitschrift fur angewandte Ichthyologie》2021,37(4):563-571
The chromosomal characteristics of Clarias magur were examined using conventional (Giemsa-staining, Ag-impregnation and CMA3 + DAPI fluorescence) and molecular/ FISH (18S & 5S rDNA probes + one BAC DNA probe) cytogenetic tools. The diploid chromosome number was 50 and the karyotype consisted of 14 metacentric, 20 sub-metacentric, 8 sub-telocentric, 8 acrocentric chromosomes with 84 chromosome arms without any heteromorphic pair. The C-heterochromatic blocks were located on centromeric position of 13 pairs of chromosomes. The NOR sites, visualized by AgNO3- and CMA3- staining, were situated at p arms of chromosome pair No. 21, which also corresponded to 18S rDNA site visualized by FISH. The FISH signal of ICF_001_D19 clone probe was observed on 18th chromosome pair. The findings of the present study on C. magur provided valuable markers for the chromosome identification and locations of genes of the BAC clone on the chromosome will lead to the construction of physical map of genome of this species. 相似文献
17.
Mamta Singh Ravindra Kumar N. S. Nagpure B. Kushwaha Indramani Gond W. S. Lakra 《Genetica》2009,137(3):245-252
Dual color fluorescence in situ hybridization (FISH) was performed to study the simultaneous chromosomal localization of 18S
and 5S ribosomal genes in the genus Tor for the first time. The 18S and 5S rDNAs in four Tor species were amplified, sequenced and mapped on the metaphase chromosomes. The number and distribution of 18S and 5S rDNA
clusters were examined on metaphase chromosome spreads using FISH. The specimens of T. chelynoides, T. putitora and T. progeneius showed six bright fluorescent signals of 18S rDNA and T. tor exhibited ten such signals. The 5S rDNA signals were present only on one pair of chromosomes in all the four Tor species. Ag-NORs were observed on two pairs of chromosomes in T. chelynoides, T.
putitora, T. progeneius and four pairs in T. tor. Comparison of the observed 18S rDNA FISH signals and Ag-NORs strongly suggested a possible inactivation of NORs localized
at the telomeres of a subtelocentric and telocentric chromosome pairs in all four species. The 5S rDNA contained an identical
120 bp long coding region and 81 bp long highly divergent non-transcribed spacers in all species examined. 18S and 5S rDNA
sequencing and chromosomal localization can be a useful genetic marker in species identification as well as phylogenetic and
evolutionary studies. 相似文献
18.
The location of 18S and 5S rDNA sites was determined in eight species and populations of the fish genus Triportheus by using fluorescent in situ hybridization (FISH). The males and females of all species had 2n = 52 chromosomes and a ZZ/ZW sex chromosome system. A single 18S rDNA site that was roughly equivalent to an Ag-NOR was detected on the short arms of a submetacentric pair in nearly all species, and up to two additional sites were also observed in some species. In addition, another 18S rDNA cluster was identified in a distal region on the long arms of the W chromosome; this finding corroborated previous evidence that this cluster would be a shared feature amongst Triportheus species. In T. angulatus, a heterozygotic paracentric inversion involving the short arms of one homolog of a metacentric pair was associated with NORs. The 5S rDNA sites were located on the short arms of a single submetacentric chromosomal pair, close to the centromeres, except in T. auritus, which had up to ten 5S rDNA sites. The 18S and 5S rDNA sites were co-localized and adjacent on the short arms of a chromosomal pair in two populations of T. nematurus. Although all Triportheus species have a similar karyotypic macrostructure, the results of this work show that in some species ribosomal genes may serve as species-specific markers when used in conjunction with other putatively synapomorphic features. 相似文献
19.
20.
Fábio Hiroshi Takagui Natalia Bortolazzi Venturelli Tatiane Ramos Sampaio Ana Lúcia Dias Lúcia Giuliano-Caetano 《Ichthyological Research》2014,61(3):201-206
Cytogenetic analyses were performed on Corydoras britskii from the Miranda River basin, an important river located in the Pantanal, Mato Grosso do Sul State, Brazil. The karyotype of this species comprises 90 chromosomes and a karyotype formula of 4m + 10 sm + 22 st + 54a. The nucleolus organizer regions were detected by impregnation with silver nitrate and FISH with an 18S rDNA probe on the short arm of three acrocentric chromosomes. The constitutive heterochromatin is distributed in pericentromeric and interstitial positions, and also associated with the NORs. The HinfI restriction endonuclease was used and showed homology with practically all types of heterochromatin observed in C. britskii, except for two interstitial heterochromatic blocks present in a subtelocentric pair. The fluorochrome staining evidenced six chromosomes with chromomycin-positive signals indicating that both the heterochromatin interspersed with NORs and some heterochromatic blocks were rich in GC base pairs. FISH using a 5S rDNA probe revealed the presence of these regions in only one subtelocentric pair in the interstitial position. The obtained data substantiate the karyotype diversity of the genus Corydoras and provide novel information about the composition of heterochromatin and location of 5S and 18S rDNA sites. 相似文献