scholarly journals Patterns of chromosomal variation in Mexican species of Aeschynomene (Fabaceae, Papilionoideae) and their evolutionary and taxonomic implications

2020 ◽  
Vol 14 (1) ◽  
pp. 157-182
Author(s):  
Fernando Tapia-Pastrana ◽  
Alfonso Delgado-Salinas ◽  
Javier Caballero
Keyword(s):  
Chromosome Number ◽  
Chromosome Size ◽  
Chromosomal Variation ◽  
Chromosomal Structure ◽  
Circular Dna ◽  
Spherical Structure ◽  
Taxonomic Implications ◽  
Diploid Level ◽  
Mexican Species ◽  
Karyotype Heterogeneity

A cytogenetic analysis of sixteen taxa of the genus Aeschynomene Linnaeus, 1753, which includes species belonging to both subgenera Aeschynomene (Léonard, 1954) and Ochopodium (Vogel, 1838) J. Léonard, 1954, was performed. All studied species had the same chromosome number (2n = 20) but exhibited karyotype diversity originating in different combinations of metacentric, submetacentric and subtelocentric chromosomes, chromosome size and number of SAT chromosomes. The plasticity of the genomes included the observation in a taxon belonging to the subgenus Aeschynomene of an isolated spherical structure similar in appearance to the extra chromosomal circular DNA observed in other plant genera. By superimposing the karyotypes in a recent phylogenetic tree, a correspondence between morphology, phylogeny and cytogenetic characteristics of the taxa included in the subgenus Aeschynomene is observed. Unlike subgenus Aeschynomene, the species of Ochopodium exhibit notable karyotype heterogeneity. However the limited cytogenetic information recorded prevents us from supporting the proposal of their taxonomic separation and raise it to the genus category. It is shown that karyotype information is useful in the taxonomic delimitation of Aeschynomene and that the diversity in the diploid level preceded the hybridization/polyploidization demonstrated in the genus. The systematic implications of our results and their value can be extended to other Dalbergieae genera as knowledge about the chromosomal structure and its evolution increases.

Chromatin Diminution in Cyclops kolensis Lill. (Copepoda, Crustacea) as a Radical Way to Inactivate Redundant Genome in Somatic Cells

2018 ◽  
Vol 156 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Andrey K. Grishanin ◽  
Maxim V. Zagoskin
Keyword(s):  
Chromosome Number ◽  
Repetitive Sequences ◽  
Early Embryogenesis ◽  
Chromosome Size ◽  
Chromatin Diminution ◽  
Elimination Process ◽  
Dna Elimination ◽  
Molecular Studies ◽  
Cyclops Kolensis

Chromatin diminution (CD) is a phenomenon of programmed DNA elimination which takes place in early embryogenesis in some eukaryotes. The mechanism and biological role of CD remain largely unknown. During CD in the freshwater copepod Cyclops kolensis, the genome of cells of the somatic lineage is reorganized and reduced in size by more than 90% without affecting the genome of germline cells. Although the diploid chromosome number is unchanged, chromosome size is dramatically reduced by CD. The eliminated DNA consists primarily of repetitive sequences and localizes within granules during the elimination process. In this review, we provide an overview of CD in C. kolensis including both cytological and molecular studies.

Karyological study in fifteen Leucocoryne taxa (Alliaceae)

Biologia ◽  
2012 ◽  
Vol 67 (2) ◽  
Author(s):  
Paola Jara-Arancio ◽  
Pedro Jara-Seguel ◽  
Claudio Palma-Rojas ◽  
Gina Arancio ◽  
Raul Moreno
Keyword(s):  
Chromosome Number ◽  
Secondary Constriction ◽  
Chromosome Morphology ◽  
Chromosome Size ◽  
Chromosome Fusion ◽  
Karyological Study ◽  
Karyotype Asymmetry ◽  
Additional Chromosome ◽  
Karyotype Formula ◽  
Haploid Karyotype

AbstractThe karyotype of fifteen Leucocoryne taxa was studied, assessing characteristics such as chromosome morphology and size, secondary constriction location, and asymmetry level. Two groups of Leucocoryne taxa were described based on chromosome number (2n = 10 and 2n = 18) and karyotype asymmetry. The haploid karyotype formula for the group 2n = 10 was 3m + 2st (or 2t), whereas for the group 2n = 18 was 7m + 2st (or 2t). Such results corroborate the karyotype descriptions previously carried out for some taxa of the genus. Leucocoryne taxa showed a high resemblance in chromosome morphology, but inter-specific differences were found in mean chromosome size. These data and previous studies based on gross chromosome morphology support Crosa’s hypothesis, which suggests that the cytotype 2n = 10 is diploid and perhaps ancestral, whereas that the cytotype 2n = 18 is tetraploid but with an additional chromosome fusion being probably a derived status.

scholarly journals Nucleic acid content and Chromosome morphology in Chrysanthemum

1969 ◽  
Vol 13 (3) ◽  
pp. 241-250 ◽  
Author(s):  
G. J. Dowrick ◽  
A. S. El Bayoumi
Keyword(s):  
Nucleic Acid ◽  
Chromosome Number ◽  
Dna Content ◽  
Chromosome Numbers ◽  
Chromosome Length ◽  
Chromosome Morphology ◽  
Nucleic Acid Content ◽  
Chromosome Size ◽  
Dna Contents ◽  
The Relationship

1. The DNA contents of twenty-eight different species and forms of Chrysanthemum have been measured by photometry. It is shown that there are large differences in DNA content between some species with identical chromosome numbers.2. The DNA contents of natural polyploids are frequently not those expected when comparison is made with diploid forms of the same species. The DNA contents of induced polyploids are those expected.3. Chromosome length and volume are positively correlated with DNA content.4. The relationship between chromosome number, chromosome size, DNA content and gene number is considered, and it is suggested that the differences in DNA content may result from the presence of differing amounts of genetically inactive DNA in the chromosomes.

scholarly journals Additional karyological dataon goitered gazelle, Gazella subgutturosa, from Turkey

2009 ◽  
Vol 61 (1) ◽  
pp. 45-48
Author(s):  
Coşkun Tez ◽  
Akalin Hilal ◽  
Münife Erkekkardeş
Keyword(s):  
Chromosome Number ◽  
Conservation Biology ◽  
Diploid Chromosome Number ◽  
Chromosomal Variation ◽  
Gazella Subgutturosa

The chromosomes of goitered gazelle, Gazella subgutturosa, in Turkey were karyotyped on the basis of two female specimens. Bothspecimens have 2n = 30 with NF = 60 and NFa = 56. All chromosomes are biarmed. The two female specimens of Turkish G. subgutturosa have a smaller diploid chromosome number compared to those of two males previously reported. This chromosomal variation in Turkish G. subgutturosa may be important for its conservation biology.

Hypoxylon serpens: cytology and taxonomic considerations

1975 ◽  
Vol 53 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Jack D. Rogers
Keyword(s):  
Chromosome Number ◽  
Haploid Chromosome Number ◽  
Taxonomic Implications

The haploid chromosome number of Hypoxylon serpens is seven. Ascospores are initially uninucleate, becoming binucleate after a mitosis. One nucleus is cut off in a cellular appendage which degenerates before ascospores become colored. Mature ascospores are uninucleate and devoid of appendages. Taxonomic implications of these data are discussed.

scholarly journals Interphase nuclear phenotype and chromosomal variation in Cynodon dactylon (L.) pers

2019 ◽  
Vol 27 ◽  
pp. 133-141
Author(s):  
SK Nitu ◽  
SMS Islam ◽  
H Tarique
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Somatic Chromosome ◽  
Cynodon Dactylon ◽  
Nuclear Organization ◽  
Nuclear Volume ◽  
Chromosomal Variation ◽  
Nuclear Area ◽  
Somatic Chromosome Number ◽  
Interphase Chromosome

Interphase nuclear phenotype in different accessions (Acc.) of Cynodon dactylon studied in the present experiment showed chromocentric nuclear organization and the chromocenters were found to be visible clearly. The chromocenter numbers were not same and sometimes it was found to be significantly less and never more than total number of chromosomes. Percentages of heterochromatin values were expressed per nuclear area and the values range from 19.759% (Acc. 16) to 66.022% (Acc.18). Nuclear volume as well as interphase chromosome volume was found to vary 0.674 μm3 (Acc.6) to 41.921 μm3 (Acc.10) and from 0.028 μm3 (Acc. 6) to 1.905 μm3 (Acc. 10), respectively. The somatic chromosome number found to vary from 12 to 40. 2n = 18 chromosomes were found in eight accessions of C. dactylon. Only one accession was found to be tetraploid and rest of them aneuploid whose chromosome numbers were 12, 14, 16, 22, 24, 26, 32, 40 etc. The availability of aneuploid shows great aspects of forage breeding programme. J. bio-sci. 27: 133-141, 2019

Chromosome Number Variation in the Myrtaceae and Its Taxonomic Implications

1979 ◽  
Vol 27 (5) ◽  
pp. 547 ◽  
Author(s):  
BL Rye
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Evolutionary Potential ◽  
The Family ◽  
Number Variation ◽  
Taxonomic Implications ◽  
Chromosome Number Variation ◽  
Australian Flora ◽  
Base Chromosome Number ◽  
Western Australian

New chromosome number determinations are reported for some 150 Western Australian species of the Myrtaceae. These include the lowest number (n = 5) so far recorded in the family and several newly recorded descending dysploid series. Dysploid chromosome numbers are far less common than the base chromosome number of n = 11 but parallel dysploid series have occurred in many groups and some have played a role in the origin of genera. Polyploidy has been successful at the intraspecific and interspecific levels but is of limited evolutionary potential. The cytoevolutionary trends in the Myrtaceae are examined in relation to taxonomic problems within the family and in relation to cytoevolution in the woody Australian flora as a whole. Smith- White's suggestion that a more natural generic classification in the Chamelauciinae could be obtained by grouping species with the same base chromosome numbers is found to be untenable.

Genome size variation in Begonia

Genome ◽  
2009 ◽  
Vol 52 (10) ◽  
pp. 829-838 ◽  
Author(s):  
Angelo Dewitte ◽  
Leen Leus ◽  
Tom Eeckhaut ◽  
Ives Vanstechelman ◽  
Johan Van Huylenbroeck ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Chromosome Number ◽  
Genome Size ◽  
Size Variation ◽  
South American ◽  
Chromosome Size ◽  
Genome Size Variation ◽  
Length Width ◽  
South American Origin ◽  
Secondary Constrictions

The genome sizes of a Begonia collection comprising 37 species and 23 hybrids of African, Asiatic, Middle American, and South American origin were screened using flow cytometry. Within the collection, 1C values varied between 0.23 and 1.46 pg DNA. Genome sizes were, in most cases, not positively correlated with chromosome number, but with pollen size. A 12-fold difference in mean chromosome size was found between the genotypes with the largest and smallest chromosomes. In general, chromosomes from South American genotypes were smaller than chromosomes of African, Asian, or Middle American genotypes, except for B. boliviensis and B. pearcei. Cytological chromosome studies in different genotypes showed variable chromosome numbers, length, width, and total chromosome volume, which confirmed the diversity in genome size. Large secondary constrictions were present in several investigated genotypes. These data show that chromosome number and structure exhibit a great deal of variation within the genus Begonia, and likely help to explain the large number of taxa found within the genus.

Cytotaxonomy of the Festuca spp. from Patagonia

1992 ◽  
Vol 70 (6) ◽  
pp. 1134-1140 ◽  
Author(s):  
Jorge Dubcovsky ◽  
Arturo J. Martínez
Keyword(s):  
Multivariate Analysis ◽  
Chromosome Number ◽  
Key Words ◽  
Distance Matrix ◽  
Chromosome Size ◽  
Size And Shape ◽  
Cytological Data ◽  
Vegetative Characters ◽  
First Time

Chromosome number and karyotypes of Festuca argentina (2n = 28), Festuca magellanica (2n = 42 and 2n = 56), and Festuca purpurascens (2n = 42) are described here for the first time, as well as new data on the karyotype of Festuca contracta (2n = 42). Multivariate analysis based on chromosome size and shape showed significant (p < 0.05) differences among these species but not among the populations of F. magellanica analyzed. The correlation between a distance matrix among all the Patagonian species based on nine karyotype parameters and one based on morphoreproductive characters was significant (r = 0.60, p < 0.01) but it was not significant when compared with vegetative characters (r = 0.25, p > 0.05). The morphoreproductive and cytological data supported the classification of the Patagonian species in four different subgenera reflecting that the Patagonian Festuca spp. had different phylogenetic origins. Key words: Festuca, karyotype, cytotaxonomy.

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