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1.
The karyotype of diploid Aster iinumae is morphologically similar to that of diploid Aster ageratoides var. ageratoides, however, its chromosome size is apparently smaller (S-type chromosomes versus L-type chromosomes, respectively). The hybrid
origin of tetraploid Aster microcephalus var. ovatus (LS-type chromosomes) has previously been suggested by cytogenetics and chloroplast DNA (cp DNA) data. The cp DNA phylogeny
also implies that the S-type chromosome is apomorphic, which means that genome size reduction occurred on the evolutionary
way to A. iinumae. In this study, we have demonstrated that the chromosome size difference does not depend on the intensity of chromosome condensation
but on the DNA content. The simultaneous genomic in situ hybridization (GISH) results show the similarity between S-type chromosomes
of A. iinumae and A. microcephalus var. ovatus, and between L-type chromosomes of A. ageratoides and A. microcephalus var. ovatus, which provide additional evidence for A. microcephalus var. ovatus being a tetraploid amphidiploid produced by hybridization between S-type chromosomes and L-type chromosomes. The distribution
patterns of Ty1-copia-like retrotransposons were similar in L- and S-type chromosomes. The copies of this retrotransposon dispersed uniformly on
all chromosomes, and it is not yet apparent how the Ty1-copia-like retrotransposon affects the size difference between them. 相似文献
2.
Multicolor FISH mapping of the dioecious model plant,<Emphasis Type="Italic"> Silene latifolia</Emphasis> 总被引:8,自引:0,他引:8
Lengerova M Kejnovsky E Hobza R Macas J Grant SR Vyskot B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,108(7):1193-1199
Silene latifolia is a key plant model in the study of sex determination and sex chromosome evolution. Current studies have been based on genetic mapping of the sequences linked to sex chromosomes with analysis of their characters and relative positions on the X and Y chromosomes. Until recently, very few DNA sequences have been physically mapped to the sex chromosomes of S. latifolia. We have carried out multicolor fluorescent in situ hybridization (FISH) analysis of S. latifolia chromosomes based on the presence and intensity of FISH signals on individual chromosomes. We have generated new markers by constructing and screening a sample bacterial artificial chromosome (BAC) library for appropriate FISH probes. Five newly isolated BAC clones yielded discrete signals on the chromosomes: two were specific for one autosome pair and three hybridized preferentially to the sex chromosomes. We present the FISH hybridization patterns of these five BAC inserts together with previously described repetitive sequences (X-43.1, 25S rDNA and 5S rDNA) and use them to analyze the S. latifolia karyotype. The autosomes of S. latifolia are difficult to distinguish based on their relative arm lengths. Using one BAC insert and the three repetitive sequences, we have constructed a standard FISH karyotype that can be used to distinguish all autosome pairs. We also analyze the hybridization patterns of these sequences on the sex chromosomes and discuss the utility of the karyotype mapping strategy presented to study sex chromosome evolution and Y chromosome degeneration.Communicated by J.S. Heslop-Harrison 相似文献
3.
Bharathi LK Munshi AD Vinod Chandrashekaran S Behera TK Das AB John KJ Vishalnath 《Journal of genetics》2011,90(1):21-30
Somatic chromosome number and detailed karyotype analysis were carried out in six Indian Momordica species viz. M. balsamina, M. charantia, M. cochinchinensis, M. dioica, M. sahyadrica and M. cymbalaria (syn. Luffa cymbalaria; a taxon of controversial taxonomic identity). The somatic chromosome number 2n = 22 was reconfirmed in monoecious species (M. balsamina and M. charantia). Out of four dioecious species, the chromosome number was reconfirmed in M. cochinchinensis (2n = 28), M. dioica (2n = 28) and M. subangulata subsp. renigera (2n = 56), while in M. sahyadrica (2n = 28) somatic chromosome number was reported for the first time. A new chromosome number of 2n = 18 was reported in M. cymbalaria against its previous reports of 2n = 16, 22. The karyotype analysis of all the species revealed significant numerical and structural variations of chromosomes.
It was possible to distinguish chromosomes of M. cymbalaria from other Momordica species and also between monoecious and dioecious taxa of the genus. Morphology and crossability among the dioecious species
was also studied. Evidence from morphology, crossability, pollen viability and chromosome synapsis suggests a segmental allopolyploid
origin for M. subangulata subsp. renigera. The taxonomic status of the controversial taxon M. cymbalaria was also discussed using morphological, karyological and crossability data. 相似文献
4.
Kazama Y Sugiyama R Matsunaga S Shibata F Uchida W Hizume M Kawano S 《Journal of plant research》2003,116(4):317-326
The major satellite DNAs of the dioecious plant Silene latifolia are represented by the repetitive sequences X43.1, RMY1 and members of the SacI family, which are located at the distal ends of chromosomes. To characterize the satellite DNAs at the distal ends of the chromosomes in S. latifolia (Sl-distal-satDNA), we isolated a bacterial artificial chromosome clone (number 15B12) that contained multiple repeat sequences with KpnI restriction sites, and subcloned a portion of this sequence into a plasmid vector. Sequencing analysis confirmed that recognition or degenerate sites for KpnI were repeated 26 times at intervals of 310–324 bp in the inserted DNA. The phylogenetic tree that was constructed with the 26 KpnI repeat units contained clustered branches that were independent of the SacI family. It is clear that the KpnI repeat belongs to an Sl-distal-satDNA family that is distinct from the SacI family. We designated this family as "KpnI" after the restriction enzyme that does not have a site in the SacI family. Multi-colored fluorescent in situ hybridization was performed with the KpnI family and RMY1 probes under high stringency conditions. The results suggest that chromosome 7 is unique and that it carries the KpnI family at only one end. 相似文献
5.
We describe a new karyotype for Cavia magna Ximenez, 1980 from an estuarine island and the karyotype of Cavia aperea Erxleben, 1777 from an adjacent mainland. The species have differences in diploid number (2n), autosomal fundamental number,
quantity, and distribution of heterochromatin as dissimilar distributions of the nucleolus-organizing regions (Ag-NORs). The
C. aperea karyotype has a diploid number of 64 as previously reported for C. aperea and most other Cavia species. In contrast, this new C. magna karyotype exhibits a variant diploid number of 2n = 62, considering that previous work reported a karyotype of 2n = 64 for
C. magna. The discovery of a distinct diploid number within C. magna represents the first record of intra-specific chromosomal variation in a species of Caviidae. The diploid number of 2n = 62,
heterochromatin quantity, Ag-NOR distributions, and inversed X chromosome from this population of C. magna are as seen in the geographically proximate (Cavia intermedia Cherem Olimpio and Ximenez; intermediate Cavy). These data provide further evidence supporting C. magna as the sister species of C. intermedia. 相似文献
6.
Several chromosome types have been recognized in Citrus and related genera by chromomycin A3 (CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species
or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata (“Barnes”, “Fawcett”, “Flying Dragon”, “Pomeroy”, “Rubidoux”, “USDA”) and one P. trifoliata × C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed
a similar CMA+ banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome
with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling
was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them
co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band
of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore,
this B chromosome can be used as a marker to recognize the intergeneric Poncirus × Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S
and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated
is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic
cell fusions involving trifoliate orange germplasm.
During the submission of this paper, we analyzed 25 other citrus cultivars with the same methodology and we found that the
chromosome marker reported here can indeed distinguish Poncirus trifoliata from grapefruits, pummelos, and one variegated access of Citrus, besides the previously reported access of limes, limons, citrons, and sweet-oranges. However, among 14 mandarin cultivars,
two of them displayed a single B/5S-45S chromosome, whereas in Citrus hystrix D.C., a far related species belonging to the Papeda subgenus, this chromosome type was found in homozygosis. Since these two mandarin cultivars are probably of hybrid origin,
we assume that for almost all commercial cultivars and species of the subgenus Citrus this B type chromosome is a useful genetic marker. 相似文献
7.
Here we present the first data on chromosome banding forCapra falconeri heptneri (Zalkin, 1945) (Bovidae: Caprinae), a critically endangered subspecies of the markhor, and compare its G- and C-banding patterns
with those of the congeneric Alpine ibexC. ibex Linnaeus, 1758 and the evolutionarily more distant cattleBos taurus Linnaeus, 1758. The two goat species have identical karyotypes whereasB. taurus, which has the same diploid number (2n = 60) and autosomal fundamental number (aFN) differs in the morphology of two pairs
of autosomes (9 and 14) and of the X chromosome, as well as in the amount of C heterochromatin. Although the study supports
the earlier idea of karyotype homogeneity within the genusCapra, new comparative cytogenetic data for unstudied yet congeneric and other related species are necessary for our understanding
of the pattern of chromosome evolution within the subfamily Caprinae and, more broadly, the family Bovidae. 相似文献
8.
F. Mazzei L. Ghigliotti Jean-Pierre Coutanceau H. W. DetrichIII V. Prirodina C. Ozouf-Costaz E. Pisano 《Polar Biology》2008,31(5):629-634
The Falkland’s mullet, Eleginops maclovinus, is the only modern representative of the Sub-Antarctic family Eleginopidae, suborder Notothenioidei. Based on specimens
from the Falkland Islands/Islas Malvinas, the Magellan Straits, and the southern coast of Chile, we have established the specific
karyotype by conventional cytogenetic methods and have mapped the chromosomal loci of the ribosomal genes by fluorescence
in situ hybridization (FISH). With respect to the basal notothenioid family Bovichtidae and to the hypothetical basal condition
of the suborder (diploid number = 48, fundamental number = 48), E. maclovinus displays a slightly derived karyotype (diploid number = 48, fundamental number = 54). In contrast to the bovichtids, the
45S and 5S ribosomal DNAs are co-localized to a single chromosome pair. Condensation of the ribosomal genes to a single locus
is likely to represent an intermediate stage in the evolution of notothenioid karyology. Features unique to E. maclovinus (e.g., morphology of its large, rDNA-bearing chromosome pair) probably result from divergence during the long evolutionary
isolation of the family. 相似文献
9.
Muravenko OV Yurkevich OY Bolsheva NL Samatadze TE Nosova IV Zelenina DA Volkov AA Popov KV Zelenin AV 《Genetica》2009,135(2):245-255
Karyotypes of species sects. Linum and Adenolinum have been studied using C/DAPI-banding, Ag-NOR staining, FISH with 5S and
26S rDNA and RAPD analysis. C/DAPI-banding patterns enabled identification of all homologous chromosome pairs in the studied
karyotypes. The revealed high similarity between species L. grandiflorum (2n = 16) and L. decumbens by chromosome and molecular markers proved their close genome relationship and identified the chromosome number in L. decumbens as 2n = 16. The similarity found for C/DAPI-banding patterns between species with the same chromosome numbers corresponds with
the results obtained by RAPD-analysis, showing clusterization of 16-, 18- and 30-chromosome species into three separate groups.
5S rDNA and 26S rDNA were co-localized in NOR-chromosome 1 in the genomes of all species investigated. In 30-chromosome species,
there were three separate 5S rDNA sites in chromosomes 3, 8 and 13. In 16-chromosome species, a separate 5S rDNA site was
also located in chromosome 3, whereas in 18-chromosome species it was found in the long arm of NOR-chromosome 1. Thus, the
difference in localization of rDNA sites in species with 2n = 16, 2n = 30 and 2n = 18 confirms taxonomists opinion, who attributed these species to different sects. Linum and Adenolinum, respectively. The
obtained results suggest that species with 2n = 16, 2n = 18 and 2n = 30 originated from a 16-chromosome ancestor. 相似文献
10.
This study used karyological techniques to determine the chromosome numbers and morphology of eight species of Onobrychis L. (O. caput-galli (L.) Lam, O. aequidentata (Sibth. & Sm.) d’ Urv, O. fallax Freyn & Sint. var. fallax, O. lasiostachya Boiss, O. viciifolia Scop., O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu, O. hypargyrea Boiss. and O. cappadocica Boiss.). The results of this study determined the chromosome numbers of O. cappadocica as 2n = 16; O. viciifolia as 2n = 28 and the other species as 2n = 14 The karyotypes of species consisted of median-centromeric (m) or submedian-centromeric (sm) chromosomes. However, O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu was found to have only the median-centromeric (m) chromosomes. According to the results of the present
study, of the eight Onobrychis taxa, only O. hypargyrea has a pair of satellite chromosomes (sat-chromosome). Furthermore, this study detected karyotype asymmetry. 相似文献
11.
Paratelmatobius and Scythrophrys are leptodactylid frogs endemic to the Brazilian Atlantic forest and their close phylogenetic relationship was recently inferred
in an analysis that included Paratelmatobius sp. and S. sawayae. To investigate the interspecific relationships among Paratelmatobius and Scythrophrys species, we analyzed a mitochondrial region (approximately 2.4 kb) that included the ribosomal genes 12S and 16S and the
tRNAval in representatives of all known localities of these genera and in 54 other species. Maximum parsimony inferences were
done using PAUP* and support for the clades was evaluated by bootstrapping. A cytogenetic analysis using Giemsa staining,
C-banding and silver staining was also done for those populations of Paratelmatobius not included in previous cytogenetic studies of this genus in order to assess their karyotype differentiation. Our results
suggested Paratelmatobius and Scythrophrys formed a clade strongly supported by bootstrapping, which corroborated their very close phylogenetic relationship. Among
the Paratelmatobius species, two clades were identified and corroborated the groups P.
mantiqueira and P. cardosoi previously proposed based on morphological characters. The karyotypes of Paratelmatobius sp. 2 and Paratelmatobius sp. 3 described here had diploid chromosome number 2n = 24 and showed many similarities with karyotypes of other Paratelmatobius representatives. The cytogenetic data and the phylogenetic analysis allowed the proposal/corroboration of several hypotheses
for the karyotype differentiation within Paratelmatobius and Scythrophrys. Namely the telocentric pair No. 4 represented a synapomorphy of P. cardosoi and Paratelmatobius sp. 2, while chromosome pair No. 5 with interstitial C-bands could be interpreted as a synapomorphy of the P. cardosoi group. The NOR-bearing chromosome No. 10 in the karyotype of P. poecilogaster was considered homeologous to chromosome No. 10 in the karyotype of Scythrophrys sp., chromosome No. 9 in the karyotype of Paratelmatobius sp. 1, chromosome No. 8 in the karyotypes of Paratelmatobius sp. 2 and of Paratelmatobius sp. 3, and chromosome No. 7 in the karyotype of P. cardosoi. A hypothesis for the evolutionary divergence of these NOR-bearing chromosomes, which probably involved events like gain
in heteochromatin, was proposed. 相似文献
12.
Huseyin Inceer Sema Hayirlioglu-Ayaz Halil Selim Guler Nursen Aksu Melahat Ozcan 《Plant Systematics and Evolution》2012,298(4):827-834
The karyotypes of nine Tanacetum taxa distributed in north-east Anatolia, Turkey, were determined and evaluated by cluster analysis and principal-components
analysis. Chromosome numbers were 2n = 2x = 18 (8 taxa) and 4x = 36 (1 taxon). Somatic chromosome numbers of two taxa and a new ploidy level in one taxon are reported for the first time.
Karyotype analysis indicated that chromosomes of Tanacetum taxa have predominantly median centromeres. The taxa studied differed significantly in the size of the short arms and long
arms, and the arm ratio of each pair of homologous chromosomes, indicating structural rearrangements of the chromosomes have
been involved in diversification of the taxa. They were placed in 2A, 3A, and 2B of Stebbins’ karyotype classification, showing
the presence of a primitive symmetrical karyotype in the genus. Several systematic and evolutionary aspects of the genus are
discussed on the basis of karyological data. 相似文献
13.
Puerma E Acosta MJ Barragán MJ Martínez S Marchal JA Bullejos M Sánchez A 《Genetica》2008,134(3):287-295
The karyotype of individuals of the species Rhinolophus hipposideros from Spain present a chromosome number of 2n = 54 (NFa = 62). The described karyotype for these specimens is very similar to another previously described in individual
from Bulgaria. However, the presence of one additional pair of autosomal acrocentric chromosomes in the Bulgarian karyotype
and the differences in X chromosome morphology indicated that we have described a new karyotype variant in this species. In
addition, we have analyzed several clones of 1.4 and 1 kb of a PstI repeated DNA sequence from the genome of R. hipposideros. The repeated sequence included a region with high identity with the 5S rDNA genes and flanking regions, with no homology
with GenBank sequences. Search for polymerase III regulatory elements demonstrated the presence of type I promoter elements
(A-box, Intermediate Element and C-box) in the 5S rDNA region. In addition, upstream regulatory elements, as a D-box and Sp1
binding sequences, were present in flanking regions. All data indicated that the cloned repeated sequences are the functional
rDNA genes from this species. Finally, FISH demonstrated the presence of rDNA in nine chromosome pairs, which is surprising
as most mammals have only one carrier chromosome pair. 相似文献
14.
I. N. Moreva O. A. Radchenko A. V. Petrovskaya S. A. Borisenko 《Russian Journal of Genetics》2017,53(9):1030-1041
Molecular genetic and karyological analyses of antlered sculpin, Enophrys diceraus, from the Sea of Japan and the Sea of Okhotsk were carried out. The karyotype of this species was studied for the first time. On the basis of karyological analysis, it was established that E. diceraus from the Sea of Japan and the Sea of Okhotsk was polymorphic in terms of the number of chromosomes and their morphology (2n = 36, 35, and 37, NF = 40). It was suggested that the karyotype with 35 chromosomes could have been produced as a result of Robertsonian translocation; the karyotype with 37 chromosomes could have been produced by crossing of individuals with different number of chromosomes. On the basis of the molecular genetic analysis of the mitochondrial COI and 16S rRNA genes, considerable differences between E. diceraus from the Sea of Japan and the Sea of Okhotsk corresponding to the level of interspecies genetic variability were established. It is concluded that E. diceraus from the Sea of Japan belongs to another species, most likely, E. namiyei. 相似文献
15.
Our goal in this work was to develop a method to minimize the chromosomes of Aspergillus oryzae, to arrive at a deeper understanding of essential gene functions that will help create more efficient industrially useful
strains. In a previous study, we successfully constructed a highly reduced chromosome 7 using multiple large-scale chromosomal
deletions (Jin et al. in Mol Genet Genomics 283:1–12, 2010). Here, we have created a further reduced chromosome A. oryzae mutant harboring a reduced chromosome 7 and a reduced chromosome 8 both of which contain a large number of non-syntenic blocks.
These are the smallest A. oryzae chromosomes that have been reported. Protoplast fusion between the two distinct chromosome-reduced mutants produced a vigorous
and stable fusant which was isolated. PCR and flow cytometry confirmed that two kinds of nuclei, derived from the parent strains,
existed in this fusant and that the chromosome DNA per nucleus was doubled, suggesting that the fusant was a heterozygous
diploid strain. By treating the cell with 1 μg/ml benomyl, cell nuclei haploidization was induced in the stable diploid strain.
Array comparative genomic hybridization and pulsed-field gel electrophoresis confirmed that the reduced chromosomes 7 and
8 co-existed in the haploid fusant and that no other chromosomal modifications had occurred. This method provides a useful
tool for chromosome engineering in A. oryzae to construct an industry-useful strain. 相似文献
16.
Yueh-Hsiang Yu Yi-Wen Lin Jane-Fang Yu Werner Schempp Pauline H Yen 《BMC evolutionary biology》2008,8(1):96
Background
The Azoospermia Factor c (AZFc) region of the human Y chromosome is a unique product of segmental duplication. It consists almost entirely of very long amplicons, represented by different colors, and is frequently deleted in subfertile men. Most of the AZFc amplicons have high sequence similarity with autosomal segments, indicating recent duplication and transposition to the Y chromosome. The Deleted in Azoospermia (DAZ) gene within the red-amplicon arose from an ancestral autosomal DAZ-like (DAZL) gene. It varies significantly between different men regarding to its copy number and the numbers of RNA recognition motif and DAZ repeat it encodes. We used Southern analyses to study the evolution of DAZ and AZFc amplicons on the Y chromosomes of primates. 相似文献17.
Karyotype study was performed in 13 populations of 11 Silene species (sect. Auriculatae L., Caryophyllaceae) growing in Iran. All the species studied showed 2n = 2x = 24 chromosome number supporting the earlier report on S. meyeri, while the chromosome number of S. palinotricha, S. sojakii, S. gertraudiae, S. elymaitica, S. pseudonurensis, S. dschuparensis, S. eriocalycina, S. araratica,
S. prilipkoana and S. commelinifolia are new to science. The chromosomes were mainly metacentric or sub-metacentric and their size varied from 1.10 μm in S. pseudonurensis to 7.11 μm in S. dschuparensis. The species studied differed significantly in the total size of the chromosomes, the size of the short arms and the long
arms, indicating the role of quantitative genomic changes in the Silene species diversification. They also differ in their karyotype formulae indicating the occurrence of structural changes in
their chromosomes. The Silene species were placed in 1A, 2A, 1B and 2B classes of Stebbins karyotype symmetry showing symmetrical
karyotypes. Clustering of the species based on karyotype features grouped the species of S. palinotricha, S. prilipkoana, S. commelinifolia, S. eriocalycina, S. meyeri, S. araratica and S. Sojakii together while the species of S. gertraudiae and S. elymaitica showed more similarity and were placed close to each other. 相似文献
18.
Peterka H Budahn H Schrader O Ahne R Schütze W 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(1):30-41
In rape (Brassica napus), no resistance to the beet cyst nematode (BCN) Heterodera schachtii is available. This study was carried out to determine the specific chromosome(s) of resistant radish (Raphanus sativus) carrying the gene(s) for nematode resistance as a prequisite to convert rape from a host into a trap crop for this pest. A Raphanobrassica progeny of 25 plants was analyzed which segregated for all nine chromosomes of the Raphanus genome in a genetic background of synthetic rape. The number of radish chromosomes was determined by fluorescence in situ hybridization, using the Raphanus-specific DNA probe pURsN; and their type was identified by chromosome-specific randomly amplified polymorphic DNA markers. Five different multiple rape–radish chromosome additions (comprising the whole set of nine radish chromosomes, a–i) were selected and crossed to rape. For each cross-progeny, the number of cysts on plant roots was counted 42 days after inoculation with a L2 larvae suspension. Simultaneously, the plants were characterized for the presence or absence of individual radish chromosomes, using sets of chromosome-specific markers. Thus, the effect of each radish chromosome on cyst number was tested. Chromosome d had a major resistance effect, whereas the presence/absence of the other radish chromosomes had nearly no influence on cyst number. Plants with added chromosome d showed a resistance level comparable with that of the radish donor parent. The analysis in the cross to rape of a plant monosomic only for chromosome d confirmed the strong effect of this chromosome on nematode resistance. A further experiment comprising seven crosses using winter rape breeding lines and monosomic addition line d as pollen parent provided the same results on a broader genetic basis. In each case, the added chromosome d in a single dosage caused nearly the full resistance of the radish donor. Resistance was independent of the glucosinolate content in the roots. The possibilities for stabilizing BCN resistance in rape and its use for other crops and nematodes are discussed.Communicated by C. Möllers 相似文献
19.
Koo DH Plaha P Lim YP Hur Y Bang JW 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(7):1346-1352
A molecular cytogenetic map of Chinese cabbage (Brassica rapa ssp. pekinensis, 2n=20) was constructed based on the 4-6-diamino-2-phenylindole dihydrochloride-stained mitotic metaphase and pachytene chromosomes and multicolor fluorescence in situ hybridization (McFISH), using three repetitive DNA sequences, 5S rDNA, 45S rDNA, and C11-350H. The lengths of mitotic metaphase chromosomes ranged from 1.46 m to 3.30 m. Five 45S and three 5S rDNA loci identified were assigned to different chromosomes. The C11-350H loci were located on all the mitotic metaphase chromosomes, except chromosomes 2 and 4. The pachytene karyotype consisted of two metacentric (chromosomes 1 and 6), five submetacentric (chromosomes 3, 4, 5, 9 and 10), two subtelocentric (chromosomes 7 and 8), and one acrocentric (chromosome 2) chromosome(s). The mean lengths of ten pachytene chromosomes ranged from 23.7 m to 51.3 m, with a total of 385.3 m, which is 17.5-fold longer than that of the mitotic metaphase chromosomes. In the proposed pachytene karyotype, all the chromosomes of B. rapa ssp. pekinensis can be identified on the basis of chromosome length, centromere position, heterochromatin pattern, and the location of the three repetitive sequences. Moreover, the precise locations of the earlier reported loci of 5S rDNA, 45S rDNA, and Chinese cabbage tandem DNA repeat C11-350H were established using McFISH analysis. We also identified a 5S rDNA locus on the long arm of pachytene bivalent 7, which could not be detected in the mitotic metaphase chromosomes in the present and earlier studies. The deduced karyotype will be useful for structural and functional genomic studies in B. rapa. 相似文献
20.
Although the Dendranthema zawadskii complex has been known to comprise a series of polyploids (4×, 6×, 8×), we found diploid individuals (with 2n=18) to occur in four populations of D. zawadskii var. latilobum in the southern region of Korea. Karyotypes of metaphase chromosomes were diverse because numbers of metacentric, submetacentric,
and acrocentric chromosomes differ even within a population. A total of 17 karyotypes were found in 31 diploid individuals
collected from the four populations. The karyotypes were also diverse in the presence or absence of chromosomes with a secondary
constriction on a short or long arm and, if present, in the number of such chromosomes. They were further diverse in the presence
or absence of non-homologous chromosome(s), the presence or absence of a chromosome with a satellite, and, if present, how
many and where satellites are present. Almost the same pattern of diversity was found in diploid individuals (with 2n=18) of D. boreale and D. indicum as well, irrespective of whether they occur together with D. zawadskii var. latilobum or not. Structural features of chromosomes in the variously different karyotypes suggest that reciprocal translocation and
the hybridization between individuals with different karyotypes had repeatedly occurred not only in D. zawadskii var. latilobum, but also in D. boreale and D. indicum. Morphologically intermediate individuals between D. zawadskii var. latilobum and D. indicum suggests that the hybridization occur with different species as well.
Electronic Publication 相似文献