Telocentric Chromosome

2011 ◽  
Keyword(s):  
Telocentric Chromosome

Telocentric Chromosome

2012 ◽  
Keyword(s):  
Telocentric Chromosome

Transmission of an alien telocentric addition chromosome in common wheat that confers blue seed color

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 30-34 ◽  
Author(s):  
E. D. P. Whelan
Keyword(s):  
Triticum Aestivum ◽  
Common Wheat ◽  
Triticum Aestivum L ◽  
Seed Color ◽  
Chromosome Behavior ◽  
Phenotypic Markers ◽  
Telocentric Chromosome ◽  
Cytogenetic Studies ◽  
Meiotic Analyses ◽  
Color Gene

Phenotypic markers of chromosomes are useful for determining chromosome behavior in cytogenetic studies. Transmission of an alien, telocentric addition from Agropyron tricophorum (Link) Richt. that confers purple aleurone pigment and blue seed color was evaluated in common wheat (Triticum aestivum L.). Twenty-five of 2570 seeds from bagged heads of eight ditelocentric-addition sister plants were almost white rather than blue. Seven of these 25 seeds and 4 of 336 blue seeds segregated 41.4%:58.6% blue:white. Meiotic analyses showed that all plants grown from these 11 seeds were spontaneously produced monotelocentric additions. Transmission of the alien telocentric chromosome through the egg and the pollen was estimated to be 19.5 and 14.3%, respectively, based on BC1F1 seed color. About 28% of F2 and F3 seeds were blue; of these 7.4% were ditelocentric additions. The frequency of blue seed in F2 progeny from spontaneous monotelocentric additions (41.4%) was significantly greater than that of monotelocentric additions from controlled crosses (28%). Penetrance of the blue seed color gene(s) associated with the alien telocentric chromosome was good. Misclassification of seed color for 1595 BC1F1 seeds was less than 3% based on BC1F2 progeny.Key words: Agropyron tricophorum.

THE IDENTIFICATION AND MEIOTIC BEHAVIOR OF A DITELOSOMIC LINE IN AVENA SATIVA L

1970 ◽  
Vol 12 (4) ◽  
pp. 876-881 ◽  
Author(s):  
J. P. Dubuc ◽  
R. C. McGinnis
Keyword(s):  
Avena Sativa ◽  
Reciprocal Translocation ◽  
Meiotic Behavior ◽  
Telocentric Chromosome ◽  
Chromosome 20 ◽  
Ditelosomic Line ◽  
Metaphase I

A ditelosomic line was crossed with 12 identified monosomics. The metaphase I pairing was studied in the 40 + t – chromosome progenies. The telocentric chromosome was found to be homologous to the three previously identified monosomics namely, −7, −10, and −20 suggesting that the same chromosome is missing in all three lines. None of the chromosomes in monosomic condition used in the crosses except ST-7 and ST-17 from A. byzantina were involved in the reciprocal translocation present between Sun II and Garry and Rodney.The gene for normal vs. abaxial curling of the leaves was located on the short arm of chromosome 20. The genes for diploidisation and normal vs. kinky neck were located on 20L.

REACTION OF WHEAT TO COMMON ROOT ROT: LINKAGE OF A MAJOR GENE, Crr, WITH THE CENTROMERE OF CHROMOSOME 5B

1982 ◽  
Vol 24 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Ruby I. Larson ◽  
T. G. Atkinson
Keyword(s):  
Root Rot ◽  
Recombination Frequency ◽  
Major Gene ◽  
Recessive Gene ◽  
Triticum Aestivum L ◽  
Common Root ◽  
Telocentric Chromosome ◽  
Chromosome 5B ◽  
The Difference ◽  
Moderate Resistance

'Cadet' (C), a cultivar of Triticum aestivum L., carries the major recessive gene, Crr, for moderate resistance to common root incited by Cochliobolus sativus (Ito and Kurib.) Drechs. ex Dastur, on the long arm of chromosome 5B. The highly susceptible cultivar, 'Rescue' (R), has the dominant, epistatic allele, crr. The crossover distance from the centromere to this gene was estimated in the genetic background of both Cadet and Rescue. The ditelosomic for the long arm of each of the lines Ct"5BL (Crr) and Rt"5BL (crr) was crossed by the corresponding reciprocal chromosome 5B substitutions, C-R5B (crr) and R-C5B (Crr). The F1's, heterozygous for both the telocentric and the alleles, were then backcrossed by the appropriate recessive lines, Cadet and R-C5B. Each backcross plant was tested for its reaction to root rot and examined cytologically for the presence of a telocentric chromosome. The recombination frequency of the centromere, marked by the presence or absence of the telocentric, with alleles at the Crr locus was 42.9 ± 3.4% in the Cadet background. In the Rescue background, the recombination frequency was 36.1 ± 3.3%. The difference is attributed to a generally lower chiasma frequency in Rescue than in Cadet.

scholarly journals The First Karyological Analysis of the Sixbar Grouper Epinephelus sexfasciatus (Valenciennes, 1828) (Perciformes, Epinephelinae)

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Puan Pengseng ◽  
Keyword(s):  
Nucleolar Organizer ◽  
Andaman Sea ◽  
Banding Technique ◽  
Size Difference ◽  
Nucleolar Organizer Regions ◽  
Single Pair ◽  
Telocentric Chromosome ◽  
Karyotypic Analysis ◽  
Fish Samples ◽  
Southern Thailand

This study examines for the first time of karyotypic analysis and chromosomal characteristic of nucleolar organizer regions/NORs of Epinephelus sexfasciatus. The fish samples were collected from Andaman Sea, Phuket province, southern Thailand. The chromosomes were investigated using conventional Giemsa’s staining and Ag-NORs banding techniques. Fish chromosome preparations were conducted by squash technique from kidney. The results showed that the diploid chromosome number of E. sexfasciatus was 2n=48 and the fundamental number (NF, number of chromosome arms) was 48. The type of chromosomes included 24 large telocentric and 24 medium telocentric chromosomes. After Ag-NOR banding technique, single pair of NORs was observed on the short arm of medium telocentric chromosome pair 23. The idiogram shows gradually decreasing length of the chromosomes. A size difference of the largest and the smallest chromosomes is approximately two folds. The karyotype formula could be infered as: 2n(48) = 2n(48)= Lt24+Mt24.

Cytological Study of the Telocentric Chromosome in Seven Monotelotrisomics of Barley

1981 ◽  
Vol 142 (2) ◽  
pp. 267-273 ◽  
Author(s):  
R. J. Singh ◽  
T. Tsuchiya
Keyword(s):  
Cytological Study ◽  
Telocentric Chromosome

scholarly journals Hexavalents in spermatocytes of Robertsonian heterozygotes between Mus m. domesticus 2n=26 from the Vulcano and Lipari Islands (Aeolian Archipelago, Italy)

2018 ◽  
Author(s):  
Soledad Berríos ◽  
Raúl Fernández-Donoso ◽  
Jesús Page ◽  
Eliana Ayarza ◽  
Ernesto Capanna ◽  
...  
Keyword(s):  
X Chromosome ◽  
Nuclear Architecture ◽  
Mus Musculus Domesticus ◽  
Open Chain ◽  
Telocentric Chromosome ◽  
Telocentric Chromosomes ◽  
Xy Bivalent ◽  
Chromosomal Changes ◽  
A Chain ◽  
Pachytene Spermatocytes

The size and shape of the chromosomes, as well as the chromosomal domains that compose them, are determinants in the distribution and interaction between the bivalents within the nucleus of spermatocytes in prophase I of meiosis. Thus the nuclear architecture characteristic of the karyotype of a species can be modified by chromosomal changes such as Rb chromosomes. In this study we analysed the meiotic prophase nuclear organization of the heterozygous spermatocytes from Mus musculus domesticus 2n=26, and the synaptic configuration of the hexavalent formed by the dependent Rb chromosomes Rbs 6.16, 16.10, 10.15, 15.17 and the telocentric chromosomes 6 and 17. Spreads of 88 pachytene spermatocytes from two males were studied and in all of them five metacentric bivalents, four telocentric bivalents, one hexavalent and the XY bivalent were observed. About 48% of the hexavalents formed a chain or a ring of synapsed chromosomes, the latter closed by synapsis between the short arms of telocentric chromosomes 6 and 17.  About 52% of hexavalents formed an open chain of 10 synapsed chromosomal arms belonging to 6 chromosomes.  In about half of the unsynapsed hexavalents one of the telocentric chromosome short arms appears associated with the X chromosome single axis, which was otherwise normally paired with the Y chromosome.  The cluster of pericentromeric heterochromatin mostly determines the hexavalent’s nuclear configuration, dragging the centromeric regions and all the chromosomes towards the nuclear envelope similar to an association of five telocentric bivalents. These reiterated encounters between these chromosomes restrict the interactions with other chromosomal domains and might favour eventual rearrangements within the metacentric, telocentric or hexavalent chromosome subsets. The unsynapsed short arms of telocentric chromosomes frequently bound to the single axis of the X chromosome could further complicate the already complex segregation of hexavalent chromosomes.

Telocentric Chromosome

2002 ◽  
Author(s):  
Alan P. Wolffe
Keyword(s):  
Telocentric Chromosome
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