scholarly journals Nuclear volume, chromosome size and DNA content relationships in three species of Pinus.

CYTOLOGIA ◽  
1980 ◽  
Vol 45 (3) ◽  
pp. 555-560 ◽  
Author(s):  
Sukhrai S. Dhillon
Keyword(s):  
Dna Content ◽  
Nuclear Volume ◽  
Chromosome Size

scholarly journals The relationship between nuclear DNA content and centromere volume in higher plants

1981 ◽  
Vol 47 (1) ◽  
pp. 91-115 ◽  
Author(s):  
M.D. Bennett ◽  
J.B. Smith ◽  
J. Ward ◽  
G. Jenkins
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Higher Plants ◽  
Nuclear Dna Content ◽  
Close Correlation ◽  
Interspecific Variation ◽  
Nuclear Volume ◽  
Chromosome Size ◽  
Higher Plant ◽  
Single Chromosome

The total volume of centromeres per nucleus varies widely within Triticum aestivum cv. Chinese Spring (7-fold) and between 11 higher plant species (24-fold). Such variation is closely correlated with nuclear DNA content, nuclear volume and, to a lesser extent, the total volume of nucleoli per nucleus. Centromere volume reflects minor intraspecific developmental fluctuations in nuclear size independent of variation in nuclear DNA content, but variation in nuclear DNA plays the major role in determining centromere volume. Thus, in general a given total volume of centromeric material is apparently characteristic of an approximately constant nuclear volume and mass of nuclear DNA, but largely independent of chromosome number. The range of volume of single centromeres in 4 taxa corresponds with the ranges of their single chromosome lengths or chromosome DNA contents. The centromere is, therefore, not a unit structure of constant size and mass but a chromosome segment whose highly variable volume closely reflects the volume and mass of the chromosome to which it belongs. The correlation between centromere size and chromosome size and DNA content is potentially useful for identifying single centromeres in unsquashed interphase and dividing nuclei; thereby facilitating studies of the intranuclear disposition of chromosomes. The present results for centromeres provide probably the first example to indicate that variation in the total DNA content of small segments present on each chromosome sometimes varies directly in proportion to large interspecific variation in nuclear DNA C-value. The close correlation between centromere volume, and nuclear DNA content is probably nucleotypic in origin. The functional significance of the variation in centromere volume is unknown, as is the nature of the mechanism which determines that centromere volume closely reflects nuclear and chromosome size and mass.

Dna Content and Nuclear Volume in Larval Organs ofApis Mellifera

1971 ◽  
Vol 10 (3) ◽  
pp. 125-132 ◽  
Author(s):  
Maria Luiza S. Mello ◽  
Catarina S. Takahashi
Keyword(s):  
Dna Content ◽  
Nuclear Volume

DNA content and chromosome evolution in the shrubby Oxalis

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 52-57 ◽  
Author(s):  
Daniel de Azkue ◽  
Arturo Martínez
Keyword(s):  
Multivariate Analysis ◽  
Dna Content ◽  
Numerical Taxonomy ◽  
Chromosome Evolution ◽  
Chromosome Size ◽  
Size And Shape

The amount of DNA varies widely in 20 shrubby Oxalis species analyzed, ranging from 1.76 pg in O. alstonii to 33.00 pg in O. dispar. This wide variation in DNA content coincided with a wide variation in chromosome size and shape. Numerical taxonomy methods showed that this variation in chromosome size and shape in shrubby Oxalis is mainly due to extra DNA. It was also possible to arrange the 20 species examined in six different groups on the basis of karyotypic similarities.Key words: Oxalis, DNA content, chromosome evolution, multivariate analysis.

DNA content in Tradescantia

1985 ◽  
Vol 27 (6) ◽  
pp. 766-775 ◽  
Author(s):  
Arturo Martínez ◽  
Héctor D. Ginzo
Keyword(s):  
North America ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Life Forms ◽  
Chromosome Size ◽  
Polyploid Complex ◽  
Ploidy Levels ◽  
Vegetative Adaptation ◽  
The Relationship

There is a wide variation in the nuclear DNA content and chromosome size between the species belonging to the T. crassifolia and T. virginiana alliances (all the species but one are native to Central and North America). Also the DNA content per genome decreases when the ploidy level increases within the same specific polyploid complex with three ploidy levels (2x, 4x, and 6x). In contrast, no variation was found in the DNA content per genome between different ploidy levels in the T. fluminensis alliance (all the species are native to South America) where they range from 6x to 22x. Since all the species described here are perennials with various life forms, it was possible to analyze the relationship between the DNA content and their vegetative adaptation to the environment. The more specialized species (geophytes and hemicryptophytes) have a higher amount of DNA than the chamaephytes adapted to live in relatively more mesic regions. In the species living in Central and North America there is a positive correlation between the increase in DNA content and the latitude of their native regions.Key words: Tradescantia, DNA content, geographical distribution, life forms, polyploidy.

Chromosome size and DNA content of species of anemone L. and related genera (Ranunculaceae)

Chromosoma ◽  
1966 ◽  
Vol 20 (1) ◽  
pp. 54-74 ◽  
Author(s):  
Klaus Rothfels ◽  
Elizabeth Sexsmith ◽  
Margaret Heimburger ◽  
Margarida O. Krause
Keyword(s):  
Dna Content ◽  
Chromosome Size

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 The Relationship between Chromosome size and DNA Content in Birch (Betula) Species

Caryologia ◽  
1973 ◽  
Vol 26 (2) ◽  
pp. 263-273 ◽  
Author(s):  
L. Janette Taper ◽  
W. F. Grant
Keyword(s):  
Dna Content ◽  
Chromosome Size ◽  
The Relationship

Nuclear volume control by nucleoskeletal DNA, selection for cell volume and cell growth rate, and the solution of the DNA C-value paradox

1978 ◽  
Vol 34 (1) ◽  
pp. 247-278 ◽  
Author(s):  
T. Cavalier-Smith
Keyword(s):  
Cell Growth ◽  
Cell Volume ◽  
Growth Rates ◽  
Dna Content ◽  
Somatic Cells ◽  
Life Cycles ◽  
Nuclear Volume ◽  
Small Cells ◽  
Chromatin Diminution ◽  
Protein Coding

The 40,000-fold variation in eukaryote haploid DNA content is unrelated to organismic complexity or to the numbers of protein-coding genes. In eukaryote microorganisms, as well as in animals and plants, DNA content is strongly correlated with cell volume and nuclear volume, and with cell cycle length and minimum generation time. These correlations are simply explained by postulating that DNA has 2 major functions unrelated to its protein-coding capacity: (1) the control of cell volume by the number of replicon origins, and (2) the determination of nuclear volume by the overall bulk of the DNA: cell growth rates are determined by the cell volume and by the area of the nuclear envelope available for nucleocytoplasmic transport of RNA, which in turn depends on the nuclear volume and therefore on the DNA content. During evolution nuclear volume, and therefore DNA content, has to be adjusted to the cell volume to allow reasonable growth rates. The great diversity of cell volumes and growth rates, and therefore of DNA contents, among eukaryotes results from a varying balance in different species between r-selection, which favours small cells and rapid growth rates and therefore low DNA C-values, and K-selection which favours large cells and slow growth rates and therefore high DNA C-values. In multicellular organisms cell size needs to vary in different tissues: size differences between somatic cells result from polyteny, endopolyploidy, or the synthesis of nucleoskeletal RNA. Conflict between the need for large ova and small somatic cells explains why lampbrush chromosomes, nurse cells, chromatin diminution and chromosome elimination evolved. Similar evolutionary considerations clarify the nature of polygenes, the significance of the distribution of haploidy, diploidy and dikaryosis in life cycles and of double fertilization in angiosperms, and of heteroploidy despite DNA constancy in cultured cells, and other puzzles in eukaryote chromosome biology. Eukaryote DNA can be divided into genic DNA (G-DNA), which codes for proteins (or serves as recognition sites for proteins involved in transcription, replication and recombination), and nucleoskeletal DNA (S-DNA) which exists only because of its nucleoskeletal role in determining the nuclear volume (which it shares with G-DNA, and performs not only directly, but also indirectly by coding for nucleoskeletal RNA). Mechanistic and evolutionary implications of this are discussed.

A study of DNA and mitotic activity in the vegetative apex of Douglas fir during the annual growth cycle

1973 ◽  
Vol 51 (7) ◽  
pp. 1395-1409 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder
Keyword(s):  
Mitotic Activity ◽  
Dna Content ◽  
Peripheral Zone ◽  
Growth Cycle ◽  
Nuclear Volume ◽  
Annual Growth ◽  
Axillary Shoots ◽  
Volume Percentage ◽  
Leaf Initiation ◽  
Mother Cells

Vegetative apices of Pseudotsuga menziesii (Mirb.) Franco were studied throughout the annual growth cycle. When observations based on anatomy, histochemistry, and external morphology are combined, the growth cycle of the vegetative apex should be subdivided into five stages: (1) dormancy, (2) early bud-scale initiation, (3) late bud-scale initiation and rapid apical enlargement, (4) early, rapid leaf initiation, and (5) late, slow leaf initiation. The same cytohistological zonation pattern is present in vegetative apices throughout the growth cycle and usually consists of apical, peripheral, and rib meristem zones. During dormancy, early bud-scale initiation, and early leaf initiation, the apical zone is separated into apical initials and central mother cells based on nuclear characteristics and mitotic activity. Cytohistological zonation is supported by constant differences in nuclear volume, mitotic activity, and DNA content between zones. The peripheral zone is mitotically more active than the apical zone; however, the apical zone is not quiescent. Zones vary in size, prominence, and mitotic activity, which often relates to a particular developmental stage of the apex. The dormant apex has no mitotic activity, and cytohistological zonation is present but not distinct. Zonation increases throughout the first half of the growing season, reaches a maximum during late bud-scale and early leaf initiation, and decreases as dormancy approaches. In general, increases in nuclear volume, percentage of nuclei at 4C, and average DNA content per nucleus correlate with increases in the prominence of zonation. Zonation did not result from different zones being "held" at certain C levels of DNA. Although nuclear volume was used in calculating the DNA content, the DNA level often varied independently of volume. Mitotic activity and dormancy appear to be related to carbohydrate levels within the bud and subtending shoot. The period of most prominent zonation is also the period of most active primordial initiation, largest apical size, and the time when new axillary shoots become determined in their pathway of development.

Sign in / Sign up

Export Citation Format

Share Document