Chromosome structure of Triticum timopheevii relative to T. turgidum

Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 923-930 ◽  
Author(s):  
S Rodríguez ◽  
E Perera ◽  
B Maestra ◽  
M Díez ◽  
T Naranjo
Keyword(s):  
Chromosome Structure ◽  
Triticum Turgidum ◽  
Chromosomal Rearrangements ◽  
In Situ Hybridisation ◽  
Triticum Timopheevii ◽  
C Banding ◽  
Genomic In Situ Hybridisation ◽  
Banding Analysis ◽  
Wild Accessions ◽  
Species Specific

The chromosome structure of four different wild populations and a cultivated line of Triticum timopheevii (2n = 28, AtAtGG) relative to Triticum turgidum (2n = 28, AABB) was studied, using genomic in situ hybridisation (GISH) and C-banding analysis of meiotic configurations in interspecific hybrids. Two wild accessions and the cultivated line showed the standard C-banding karyotype. The other two accessions are homozygous for translocation 5At/3G and translocations 1G/2G and 5G/6G. GISH analysis revealed that all the T. timopheevii accessions carry intergenome translocations 6At/1G and 1G/4G and identified the position of the breakpoint in translocation 5At/3G. C-banding analysis of pairing at metaphase I in the hybrids with T. turgidum provides evidence that four species-specific translocations (6AtS/1GS, 1GS/4GS, 4GS/4AtL, and 4AtL/3AtL) exist in T. timopheevii, and that T. timopheevii and T. turgidum differ in the pericentric inversion of chromosome 4A. Bridge plus acentric fragment configurations involving 4AL and 4AtL were identified in cells at anaphase I. This result suggests that the paracentric inversion of 4AL from T. turgidum does not exist in T. timopheevii. Both tetraploid species have undergone independent and distinct evolutionary chromosomal rearrangements. The position, intercalary or subdistal, of the breakpoints in species-specific translocations and inversions contrasts with the position, at or close to the centromere, of intraspecific translocations. Different mechanisms for intraspecific and species-specific chromosome rearrangements are suggested.Key words: Triticum timopheevii, chromosome pairing, translocation, evolution, C-banding, GISH.

scholarly journals Cytogenetical analyses in three fish species of the genus Pimelodus(Siluriformes: Pimelodidae) from rio São Francisco: considerations about the karyotypical evolution in the genus

2005 ◽  
Vol 3 (2) ◽  
pp. 285-290 ◽  
Author(s):  
Caroline Garcia ◽  
Orlando Moreira Filho
Keyword(s):  
Chromosome Pair ◽  
Chromosomal Rearrangements ◽  
Nucleolar Organizer ◽  
Differential Staining ◽  
Nucleolar Organizer Regions ◽  
C Banding ◽  
Heteromorphic Sex Chromosomes ◽  
Chromosomal Markers ◽  
Staining Techniques ◽  
Species Specific

Karyotypes and other chromosomal markers were investigated in three species of the catfish genus Pimelodus, namely P. fur, P. maculatus and Pimelodus sp., from municipality of Três Marias, Minas Gerais, Brazil, using differential staining techniques (C-banding, Silver nitrate and CMA3 staining). The diploid chromosome number was 2n = 56 in P. maculatus and Pimelodus sp., while in P. fur 2n = 54. The karyotype of P. fur consisted in 32M + 8SM + 6ST + 8A with fundamental number (NF) of 100, that of P. maculatus 32M + 12SM + 12A with NF = 112, and that of Pimelodus sp. had 32M + 12Sm + 6ST + 6A with NF = 106.The nucleolar organizer regions (NORs) in all three species were invariably detected in telomeres of longer arm of the 20th chromosome pair. These sites were also positive after CMA3 and C-banding. No heteromorphic sex chromosomes were detected and C-banding pattern was species specific. Inferences about the karyotype differentiation in Pimelodus and putative chromosomal rearrangements are hypohesized.

Interspecific chromosomal rearrangements in monosomic addition lines of Allium

Genome ◽  
2001 ◽  
Vol 44 (5) ◽  
pp. 929-935 ◽  
Author(s):  
L Barthes ◽  
A Ricroch
Keyword(s):  
Genomic Dna ◽  
Chromosomal Rearrangements ◽  
In Situ Hybridisation ◽  
Crossing Over ◽  
Dna Repeats ◽  
Addition Lines ◽  
Genomic In Situ Hybridisation ◽  
Chromatin Transfer ◽  
Alien Addition Lines

Monosomic alien addition lines (MAALs) are useful for assigning linkage groups to chromosomes. We examined whether the chromosomal rearrangements following the introduction of a single onion (Allium cepa) chromosome into the Allium fistulosum genome were produced by homeologous crossing over or by a nonreciprocal conversion event. Among the monosomic lines available, 17 were studied by fluorescent genomic in situ hybridisation, using total A. cepa genomic DNA as the probe and total A. fistulosum genomic DNA as the competitor. In this way, rearrangements such as chromosomal translocations between A. cepa and A. fistulosum were identified as terminal regions consisting of tandem DNA repeats. Homeologous crossing over between the two closely related genomes occurred in 4 of the 17 lines, suggesting that such events are not rare. On the basis of a detailed molecular cytogenetic characterisation, we identified true monosomic alien addition lines for A. cepa chromosomes 3, 4, 5, 7, and 8 that can reliably be used in genetic studies.Key words: chromatin transfer, genomic in situ hybridisation, GISH, monosomic alien addition lines, MAALs, Allium.

Pairing affinities of the B- and G-genome chromosomes of polyploid wheats with those of Aegilops speltoides

Genome ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 814-819 ◽  
Author(s):  
S Rodríguez ◽  
B Maestra ◽  
E Perera ◽  
M Díez ◽  
T Naranjo
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Triticum Turgidum ◽  
Aegilops Speltoides ◽  
Meiotic Pairing ◽  
Triticum Timopheevii ◽  
C Banding ◽  
Tetraploid Wheats ◽  
B Genome ◽  
Metaphase I

Chromosome pairing at metaphase I was studied in different interspecific hybrids involving Aegilops speltoides (SS) and polyploid wheats Triticum timopheevii (AtAtGG), T. turgidum (AABB), and T. aestivum (AABBDD) to study the relationships between the S, G, and B genomes. Individual chromosomes and their arms were identified by means of C-banding. Pairing between chromosomes of the G and S genomes in T. timopheevii × Ae. speltoides (AtGS) hybrids reached a frequency much higher than pairing between chromosomes of the B and S genomes in T. turgidum × Ae. speltoides (ABS) hybrids and T. aestivum × Ae. speltoides (ABDS) hybrids, and pairing between B- and G-genome chromosomes in T. turgidum × T. timopheevii (AAtBG) hybrids or T. aestivum × T. timopheevii (AAtBGD) hybrids. These results support a higher degree of closeness of the G and S genomes to each other than to the B genome. Such relationships are consistent with independent origins of tetraploid wheats T. turgidum and T. timopheevii and with a more recent formation of the timopheevi lineage.Key words: Triticum turgidum, Triticum timopheevii, Aegilops speltoides, meiotic pairing, evolution, C-banding.

The influence of fixation on the morphology of mitotic chromosomes

1986 ◽  
Vol 28 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Axel J. J. Dietrich
Keyword(s):  
Acetic Acid ◽  
Chemical Composition ◽  
Strong Influence ◽  
Chromosome Structure ◽  
Human Lymphocytes ◽  
Chromosome Morphology ◽  
Mitotic Chromosomes ◽  
Specific Chemical ◽  
C Banding ◽  
Sister Chromatids

It is well known that there is a strong influence of fixation, i.e., acetic methanol versus formaldehyde, on the chromosome morphology at stages of the first meiotic division. In this study the influence of both these types of fixation on the morphology of mitotic chromosomes was examined in human lymphocytes. After methanol – acetic acid (3:1) fixation, the chromosomes show the "classical" condensed shape in which it is not always possible to recognize the two sister chromatids. These chromosomes are accessible to the conventional G-, R-, and C-banding techniques. After formaldehyde fixation at a relatively high pH, the chromosomes are thinner and longer (two to six times) when compared with chromosomes following methanol – acetic acid fixation. They show a scaffold-like morphology, sometimes with a halo of thin material around it. In all cases the two sister chromatids could be recognized. This chromosome structure could be easily stained with silver, Giemsa, 4,6-diamino-2-phenyl-indole (DAPI), and fluorescein isocyanate isomere 1 (FITC). The results obtained following these stainings gave no indication to any specific chemical composition of a probable central scaffold. The scaffold-like structures were not accessible to G-, R-, or C-banding techniques. The only effect observed following these banding techniques was the disappearance of the halo of thin material around the central scaffold-like structure.Key words: chromosome structure, fixation influence, human lymphocytes.

scholarly journals Lack of satellite DNA species-specific homogenization and relationship to chromosomal rearrangements in monitor lizards (Varanidae, Squamata)

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Ornjira Prakhongcheep ◽  
Watcharaporn Thapana ◽  
Aorarat Suntronpong ◽  
Worapong Singchat ◽  
Khampee Pattanatanang ◽  
...  
Keyword(s):  
Satellite Dna ◽  
Chromosomal Rearrangements ◽  
Monitor Lizards ◽  
Species Specific

scholarly journals Karyotypic diversity among three species of the genus Astyanax (Characiformes: Characidae)

2016 ◽  
Vol 76 (2) ◽  
pp. 360-366 ◽  
Author(s):  
P. B. Nishiyama ◽  
M. M. R. Vieira ◽  
F. E. Porto ◽  
L. A. Borin ◽  
A. L. B. Portela-Castro ◽  
...  
Keyword(s):  
Diploid Number ◽  
Fish Fauna ◽  
Distinct Pattern ◽  
Supernumerary Chromosome ◽  
C Banding ◽  
Incertae Sedis ◽  
Banding Analysis ◽  
Karyotypic Diversity ◽  
Karyotype Formula

Abstract The group Incertae sedis within the Characidae family currently includes 88 genera, previously included in the subfamily Tetragonopterinae. Among them is the genus Astyanax comprising a group of species with similar morphology and widely distributed in the Neotropics. Thus, the present study aimed to analyze the karyotype diversity in Astyanax species from different watersheds by conventional Giemsa staining, C-banding and fluorescence in situ hybridization (FISH rDNA 18S) probe.specimens of Astyanax aff. paranae belonging to the “scabripinnis complex”, Astyanax asunsionensis and Astyanax aff. bimaculatus were analyzed”. Two sympatric karyomorphs were observed in Astyanax.aff paranae, one of them having2n=48andthe other one with 2n=50 chromosomes. Other population of this same species also presented 2n=50 chromosomes, but differing in the karyotype formula and with macro supernumerary chromosome found in 100% of the cells in about 80%of females analyzed. Two population of A. asuncionensis and one population of Astyanax. aff. bimaculatus, also showed a diploid number of 50 chromosomes, but also differing in their karyotype formulas. Therefore, A. asuncionensis was also characterized by intraspecific chromosome diversity. The C-banding analysis was able to demonstrate a distinctable to demonstrate a distinct pattern of heterochromatin differing A. asuncionensis from Astyanax aff. paranae and Astyanax aff. bimaculatus. The supernumerary chromosome of Astyanax aff. paranae proved completely heterochromatic. Only Astyanax.aff. bimaculatus multiple showed multiple sites of nucleolar organizing regions. The other species were characterized by having a simple system of NOR. These data contributes to the know ledge of the existing biodiversity in our fish fauna, here highlighted by the inter- and intraspecific chromosomal diversity in the genus Astyanax.

The synaptic behaviour of the wild forms of Triticum turgidum and T. timopheevii

Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 517-522 ◽  
Author(s):  
M Martínez ◽  
T Naranjo ◽  
C Cuadrado ◽  
C Romero
Keyword(s):  
Synaptonemal Complex ◽  
Triticum Turgidum ◽  
Genetic System ◽  
Wild Wheat ◽  
Homologous Chromosomes ◽  
Tetraploid Wheats ◽  
Ring Bivalents ◽  
In The Wild ◽  
The Mean ◽  
Wild Accessions

Different wild allopolyploid species of Triticeae show extensive bivalent formation at zygotene while a considerable number of multivalents is present in cultivated polyploid wheats. To study the chromosome behaviour at early meiotic stages in wild forms of tetraploid wheats Triticum turgidum and T. timopheevii (2n = 4x = 28) we have analysed the synaptic pattern in fully traced spread nuclei at mid- and late zygotene and at pachytene of wild accessions of these species. The mean number of synaptonemal complex (SC) bivalents at mid-zygotene ranged from 12.22 to 13.14 among the accessions studied indicating a strong restriction of synapsis initiation to homologous chromosomes. The mean of bivalents increased at pachytene because of the transformation of multivalents into bivalents. Ring bivalents observed at metaphase I support that SC bivalents were formed by homologous chromosomes. The average values of SC bivalents at mid-zygotene in the wild forms are much higher than the average values observed in the cultivated tetraploid wheats but similar to that of a mutant line of T. turgidum with a duplication that includes Ph1, the major homoeologous pairing suppressor locus. These results suggest that the efficiency of the mechanism operating in the homologous recognition for synapsis is higher in wild wheat populations than in cultivated varieties. Apparently, a relatively detrimental modification of the pairing regulating genetic system accompanied the domestication of the wild wheat forms.Key words: Ph1 locus, Triticum turgidum, Triticum timopheevii, synaptonemal complex, diploidisation.

scholarly journals Chromosome structure and behaviour in Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) germ cells and early embryo

Nematology ◽  
2006 ◽  
Vol 8 (3) ◽  
pp. 425-434 ◽  
Author(s):  
Koichi Hasegawa ◽  
Manuel M. Mota ◽  
Kazuyoshi Futai ◽  
Johji Miwa
Keyword(s):  
Germ Cells ◽  
Laser Scanning ◽  
Chromosome Structure ◽  
In Situ Hybridisation ◽  
Bursaphelenchus Xylophilus ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Fluorescence In Situ Hybridisation ◽  
Cell Stage ◽  
Male And Female

AbstractChromosome structure and behaviour in both meiosis of the germ cells and mitosis of the embryo from fertilisation to the two-cell stage in Bursaphelenchus xylophilus were examined by DAPI staining and three-dimensional reconstruction of serial-section images from confocal laser-scanning microscopy. By this method, each chromosome's shape and behaviour were clearly visible in early embryogenesis from fertilisation through the formation and fusion of the male and female pronuclei to the first mitotic division. The male pronucleus was bigger than that of the female, although the oocyte is larger and richer in nutrients than the sperm. From the shape of the separating chromosomes at anaphase, the mitotic chromosomes appeared to be polycentric or holocentric rather than monocentric. Each chromosome was clearly distinguishable in the male and female germ cells, pronuclei of the one-cell stage embryo, and the early embryonic nuclei. The haploid number of chromosomes (N) was six (2n = 12), and all chromosomes appeared similar. The chromosome pair containing the ribosomal RNA-coding site was visualised by fluorescence in situ hybridisation. Unlike the sex determination system in Caenorhabditis elegans (XX in hermaphrodite and XO in male), the system for B. xylophilus may consist of an XX female and an XY male.

scholarly journals Cytogenetics of two Farlowella species (Loricariidae: Loricariinae): implications on the taxonomic status of the species

2018 ◽  
Vol 16 (4) ◽  
Author(s):  
Leandro Marajó ◽  
Patrik F. Viana ◽  
Milena Ferreira ◽  
Lúcia H. Rapp Py-Daniel ◽  
Eliana Feldberg
Keyword(s):  
Chromosome Number ◽  
Species Complex ◽  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Taxonomic Status ◽  
Specific Marker ◽  
Genetic Studies ◽  
Molecular Cytogenetic ◽  
Metacentric Pair ◽  
Species Specific

ABSTRACT Farlowella is one of the most diverse genera of the Loricariinae, restricted to South America rivers. The taxonomic and phylogenetic relationships among its species are contentious and, while genetic studies would contribute to the understanding of their relationships, the only available datum refer to the karyotype description of only one species. In the present study two Amazonian species, Farlowella cf. amazonum and F. schreitmuelleri, were analyzed using conventional and molecular cytogenetic procedures. Both species had diploid chromosome number 58, but different fundamental numbers (NF) 116 and 112, respectively, indicative of chromosomal rearrangements. C-banding is almost poor, especially in F. cf. amazonum, and occurs predominantly in the centromeric and in some telomeric regions, although genome of F. schreitmuelleri possessed a much larger heterochromatin amount then those of F. cf. amazonum. The chromosomes bearing the NOR sites were likely the same for both species, corresponding to the 1st metacentric pair in F. cf. amazonum and to the 28th acrocentric in F. schreitmuelleri. The location of the 5S rDNA was species-specific marker. This study expanded the available cytogenetic data for Farlowella species and pointed the remarkable karyotype diversity among species/populations, indicating a possible species complex within genus.

Genome structure and evolution in the allohexaploid weed Avena fatua L. (Poaceae)

Genome ◽  
1999 ◽  
Vol 42 (3) ◽  
pp. 512-518 ◽  
Author(s):  
Q Yang ◽  
L Hanson ◽  
M D Bennett ◽  
I J Leitch
Keyword(s):  
Ribosomal Dna ◽  
Genomic Structure ◽  
In Situ Hybridisation ◽  
Avena Fatua ◽  
The Other ◽  
Morphological Data ◽  
Avena Species ◽  
Intergenomic Translocations ◽  
Genomic In Situ Hybridisation

Allohexaploid wild oat, Avena fatua L. (Poaceae; 2n = 6x = 42), is one of the world's worst weeds, yet unlike some of the other Avena hexaploids, its genomic structure has been relatively little researched. Consequently, in situ hybridisation was carried out on one accession of A. fatua using an 18S-25S ribosomal DNA (rDNA) sequence and genomic DNA fromA. strigosa (AA-genome diploid) and A. clauda (CC-genome diploid) as probes. Comparing these results with those for other hexaploids studied previously: (i) confirmed that the genomic composition of A. fatua was similar to the other hexaploid Avena taxa (i.e., AACCDD), (ii) identified major sites of rDNA on three pairs of A/D-genome chromosomes, in common with other Avena hexaploids, and (iii) revealed eight chromosome pairs carrying intergenomic translocations between the A/D- and C-genomes in the accession studied. Based on karyotype structure, the identity of some of these recombinant chromosomes was proposed, and this showed that some of these could be divided into two types, (i) those common to all hexaploid Avena species analysed (3 translocations) and (ii) one translocation in this A. fatua accession not previously observed in reports on other hexaploid Avena species. If this translocation is found to be unique to A. fatua, then this information, combined with more traditional morphological data, will add support to the view that A. fatua is genetically distinct from other hexaploid Avena species and thus should retain its full specific status.Key words: wild oats, Avena, genomic in situ hybridisation (GISH), intergenomic translocations, ribosomal DNA.

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