Evolutionary DNA variation in Papaver

Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 763-768 ◽  
Author(s):  
Sangeeta Srivastava ◽  
U. C. Lavania
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Chromosome Length ◽  
Evolutionary Divergence ◽  
Strong Positive Correlation ◽  
Dna Amount ◽  
Dna Variation ◽  
Dna Systematics ◽  
Dna Reduction

In 23 species of Papaver L., 2C nuclear DNA amounts range from 4.64 pg in Papaver persicum (2n = 14) to 22.43 pg in Papaver orientale (2n = 42), revealing a fivefold variation within the genus. However, such variation is limited to only twofold among the species that have the same chromosome number (2n = 14). The distribution of DNA is discontinuously spread over six groups in the genus. A strong positive correlation exists between nuclear DNA content and metaphase chromosome length. Viewed in the context of evolutionary divergence, it is revealed that DNA reduction has taken place in conjunction with speciation. This is achieved by equal reduction to each chromosome independent of chromosome size, as apparent from the estimated DNA values for individual chromosomes within the complements. The diminution in DNA amount with evolutionary specialisation appears to be a genomic strategy to dispense with the less important DNA associated with heterochromatic segments. The uniform distribution of such dispensible DNA throughout the complement is probably nucleotypically conducive to allow the genomic loss to be adaptationally operative, lest it affects the very survival of the evolving species.Key words: Papaver, evolution, DNA content, DNA systematics.

B-chromosome and C-band heterochromatin variation in Arizona maize populations adapted to different altitudes

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 659-662 ◽  
Author(s):  
H. L. Porter ◽  
A. Lane Rayburn
Keyword(s):  
Dna Sequences ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
B Chromosome ◽  
Chromosomal Dna ◽  
Dna Amount ◽  
Maize Populations ◽  
Dna Content Variation ◽  
Band Number

The B-chromosome and C-band numbers were determined in 12 Arizona Indian maize populations. These populations were originally collected from altitudes ranging from 100 to 5300 ft (1 ft = 0.3048 m). In addition, the total nuclear DNA amounts of these populations have been observed to vary by as much as 20%. The number of B-chromosomes was not significantly correlated with altitude, C-band number, or nuclear DNA amount. C-band number was significantly correlated with both altitude and genome size. It does not appear that the amount of C-band variation can account for the large nuclear DNA variation observed in these accessions. Additional A-chromosomal DNA sequences may be involved in the nuclear DNA content variation that exists among these accessions.Key words: heterochromatin, DNA content, evolution, repeated DNA.

scholarly journals NUCLEAR DNA CONTENT IN BLUEBERRY DETERMINED BY FLOW CYTOMETRY

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 580e-580
Author(s):  
Rodomiro Ortiz ◽  
D.E. Costich ◽  
T.P. Meagher ◽  
N. Vorsa
Keyword(s):  
Flow Cytometry ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Haploid Genome ◽  
Dna Flow Cytometry ◽  
Dna Amount ◽  
Ploidy Levels ◽  
Polyploid Evolution ◽  
Haploid Genome Size

DNA flow cytometry was used to determine nuclear DNA content in diploid blueberry species, and 3x, 4x, 5x, and 6x ploidy levels. Relative fluorescence intensity of stained nuclei measured by flow cytometry was a function of the number of chromosome sets (X): Y = 3.7X – 2.3 (r2 = 95.1%). DNA flow cytometry should be useful for ploidy level determination in the seedling stage. A significant linear relationship was established between nuclear DNA content and number of chromosomes (x); DNA (pg) = 0.52 x1 (r2 = 99.8%). Based on this equation the haploid genome DNA amount (1C) was calculated as 0.62 ± 0.08 pg, with an approximate haploid genome size of 602 Mbp/1C. The results indicate that conventional polyploid evolution occured in the section Cyanococcus, genus Vaccinium: the increase in DNA was concurrent with increase in chromosome number. DNA content differences among 2x species were correlated with Nei's genetic distance estimates based on 20 isozyme markers. Most of the variation was among species (49%), with 26% between populations within species, and 25% within populations.

Genome size and genome evolution in diploid Triticeae species

Genome ◽  
2007 ◽  
Vol 50 (11) ◽  
pp. 1029-1037 ◽  
Author(s):  
T. Eilam ◽  
Y. Anikster ◽  
E. Millet ◽  
J. Manisterski ◽  
O. Sagi-Assif ◽  
...  
Keyword(s):  
Genome Size ◽  
Intraspecific Variation ◽  
Dna Content ◽  
Nuclear Dna ◽  
Diploid Species ◽  
Nuclear Dna Content ◽  
Dna Amount ◽  
Nuclear Dna Amount ◽  
Speciation Event ◽  
Close Temporal Proximity

One of the intriguing issues concerning the dynamics of plant genomes is the occurrence of intraspecific variation in nuclear DNA amount. The aim of this work was to assess the ranges of intraspecific, interspecific, and intergeneric variation in nuclear DNA content of diploid species of the tribe Triticeae (Poaceae) and to examine the relation between life form or habitat and genome size. Altogether, 438 plants representing 272 lines that belong to 22 species were analyzed. Nuclear DNA content was estimated by flow cytometry. Very small intraspecific variation in DNA amount was found between lines of Triticeae diploid species collected from different habitats or between different morphs. In contrast to the constancy in nuclear DNA amount at the intraspecific level, there are significant differences in genome size between the various diploid species. Within the genus Aegilops , the 1C DNA amount ranged from 4.84 pg in A. caudata to 7.52 pg in A. sharonensis; among genera, the 1C DNA amount ranged from 4.18 pg in Heteranthelium piliferum to 9.45 pg in Secale montanum . No evidence was found for a smaller genome size in annual, self-pollinating species relative to perennial, cross-pollinating ones. Diploids that grow in the southern part of the group’s distribution have larger genomes than those growing in other parts of the distribution. The contrast between the low variation at the intraspecific level and the high variation at the interspecific one suggests that changes in genome size originated in close temporal proximity to the speciation event, i.e., before, during, or immediately after it. The possible effects of sudden changes in genome size on speciation processes are discussed.

Mise en évidence de variations saltatoires de l'ADN nucléaire dans et entre les espèces du genre Medicago L.

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 825-834 ◽  
Author(s):  
S. Essad
Keyword(s):  
Medicago Sativa ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
The Other ◽  
Genomic Evolution ◽  
Dna Amount ◽  
Total Amplitude ◽  
Two Samples

Forty-two samples representing 20 Medicago L. species were used to determine the nuclear DNA content of each species. Significant intra- and inter-specific variations were evident. The total amplitude of these variations at the 2C level ranged from 1.6 to 9.4 pg, but the maximum significant DNA evolutionary value amounted to 7.2 pg only (Medicago sativa 4x). The occurrence of two nuclear populations from a number of origins was interpreted as corresponding to a fundamental evolutionary value for one of them and to the addition of metabolic DNA for the other. All the values observed were near multiples of a DNA quantum called a "nucleon," which was estimated to be 0.37 pg at the 2C level. This value corresponds to the lower DNA content observed in Angiosperms. Lastly, it appears that the arithmetical distribution of one nucleon among the usual 2n = 16 chromosomes in the genus ascribes a DNA amount of 0.02 pg to each chromatid, the approximate value for a chromosome modulus.Key words: Medicago, DNA content, nucleon, chromosome modules, saltatory genomic evolution.[Journal translation]

scholarly journals Cytogenetic Characterization and Nuclear DNA Content of Diploid and Tetraploid Forms of Stokes Aster

HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2005-2012
Author(s):  
Jessica Gaus Barb ◽  
Dennis J. Werner ◽  
Shyamalrau P. Tallury
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Chromosome Length ◽  
Slight Reduction ◽  
Meiotic Pairing ◽  
Meiotic Irregularities ◽  
Cytogenetic Characterization ◽  
2C Dna Content ◽  
Chromosome Bridges

Stokesia laevis (J. Hill) Greene is a herbaceous perennial native to the southeastern United States. Most cultivars of Stokesia are diploid (2n = 2x = 14) except for ‘Omega Skyrocket’, a tetraploid (2n = 4x = 28) form selected from a natural population. A comparative study of the karyotypes and meiotic behavior of diploid cultivars, seed-derived accessions of ‘Omega Skyrocket’, synthetically derived autotetraploids, and triploid progeny from these taxa strongly suggest that ‘Omega Skyrocket’ is an autotetraploid form of Stokesia. Total karyotype length, 161 μm and 293 μm, and average chromosome length, 11.5 μm and 10.5 μm, of the diploid cultivars and tetraploid accessions of ‘Omega Skyrocket’, respectively, were determined. The karyotype of the diploid cultivars consisted of eight metacentric (m) and six submetacentric (sm) chromosomes with average arm ratio values ranging from 1.12 to 2.06. The karyotype of ‘Omega Skyrocket’ consisted of 23 m chromosomes and 5 sm chromosomes with average arm ratio values ranging from 1.22 to 2.02. Meiotic pairing in the diploids was normal. No meiotic irregularities such as laggards or bridges were observed and disjunction was balanced (7:7). Accessions of ‘Omega Skyrocket’ demonstrated a high frequency (60%) of quadrivalent formation; however, later stages of meiosis were regular with balanced disjunction (14:14) occurring in 95% of the cells. Meiotic configurations in synthetically derived autotetraploids and triploid hybrids from crosses of diploid cultivars × ‘Omega Skyrocket’ consisted of univalents, bivalents, trivalents, quadrivalents, and pentavalents. Abnormalities, including laggards, unequal and/or premature disjunction, chromosome bridges, and chromosome stickiness were observed. Average nuclear 2C DNA content was 20.3 pg for the diploid cultivars and 39.9 pg for the newly synthesized autotetraploids. Average nuclear 2C DNA content for ‘Omega Skyrocket’ was 37.3 pg, which was 8.2% less than twice the average 2C DNA content of the diploid accessions and 6.4% less than the newly synthesized autotetraploids, suggesting that genomic downsizing in ‘Omega Skyrocket’ has occurred. Similarity of the karyotypes of the diploids and ‘Omega Skyrocket’ and the slight reduction in nuclear DNA content suggest that ‘Omega Skyrocket’ has diverged little from its original diploid progenitor.

Nuclear DNA content in the Australian Bulbine (Liliaceae)

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 225-234 ◽  
Author(s):  
E. M. Watson
Keyword(s):  
Key Words ◽  
Genome Evolution ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Clinal Variation ◽  
Dna Amount ◽  
Climatic Trends ◽  
Eastern Australia ◽  
Dna Measurements

Nuclear DNA measurements for 17 Australian populations of Bulbine support the recognition of the four major groups already suggested by chromosome studies. Within the perennial group, Bulbine bulbosa s. lat., the tuberless, 46-chromosome (hypo-8x) "rock lily" has a similar DNA content to the hypo-4x, 24-chromosome populations of the "bulbosa" complex, which has populations at hypo-4x, -8x, and -12x levels. The "rock lily" also has substantially less DNA than another 46-chromosome entity, represented by the Kroombit population. Within the annual group, Bulbine semibarbata s. lat., the distinctions are less clear. However, the winged-seeded, 4x, 28-chromosome "alata" appears to have slightly more DNA than the closely related 26-chromosome "semibarbata." The 54-chromosome, 8x annual populations of eastern Australia have a DNA amount consistent with their proposed allopolyploid origin. The 52-chromosome "semibarbata" populations of Western Australia have, as expected, a lower DNA content than the 54-chromosome form and approximately twice the 4x "semibarbata" amount. It is suggested that some observed clinal variation in DNA content and an apparent DNA deficit in some of the higher polyploids of both perennial and annual groups may be attributable to climatic trends since the Miocene. Key words: Liliaceae, Bulbine, DNA content, polyploids, genome evolution.

scholarly journals Nuclear DNA Content and Ploidy Level of Apple Cultivars Including Polish ones in Relation to Some Morphological Traits

2016 ◽  
Vol 58 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Małgorzata Podwyszyńska ◽  
Dorota Kruczyńska ◽  
Aleksandra Machlańska ◽  
Barbara Dyki ◽  
Iwona Sowik
Keyword(s):  
Chromosome Number ◽  
Flowering Time ◽  
Ploidy Level ◽  
Dna Content ◽  
Nuclear Dna ◽  
Pollen Viability ◽  
Nuclear Dna Content ◽  
Pollen Grain ◽  
Clear Correlation ◽  
Dna Amount

Abstract Apple species and cultivars differ in nuclear (2C) DNA content and ploidy level. The majority of these genotypes are diploids, but there are some triploids and a few tetraploids. Nuclear DNA content is a specific feature and its flow cytometric evaluation can be helpful in differentiating taxa. For many apple genotypes – including all the Polish ones, these characteristics are not known. 2C DNA was evaluated in relation to leaf, flower, fruit, pollen grain and stomata sizes as well as to the flowering time for seventy genotypes (including 46 Polish cultivars) gathered in the gene bank of the Research Institute of Horticulture, Skierniewice, Poland. For standard cultivars with the known chromosome number, 2C value was 1.71 pg for diploid cultivar ‘Alwa’ (2n=2x=34), 2.55 pg for triploid ‘Boskoop’ (3x=51), and 3.37 pg for tetraploid genome (4x=68) of mixoploid ‘McIntosh 2x+4x’. In 61 cultivars (including 41 Polish ones), the nuclear DNA content ranged from 1.58 to 1.78 pg indicating their diploid chromosome number. Five cultivars were identified as triploids (‘Bursztówka Polska’, ‘Pagacz’, ‘Rapa Zielona’, ‘Rarytas Śląski’ and ‘Witos’) owing to their nuclear DNA amount ranging between 2.42 and 2.58 pg. Leaf, flower, fruit, stomata and pollen grain sizes were on average significantly larger in triploids. Thus, in 3x plants the mean leaf surface was 49.1 cm2, flower diameter – 52.4 mm, fruit weight – 204.7 g, stomata length – 32.1 μm and pollen grain diameter – 33.7 μm, whereas in diploids – 36.0 cm2, 46.1 mm, 162.7 g, 28.4 μm and 30.7 μm, respectively. Pollen grain viability was on average significantly higher in diploids (75.6%), compared to triploids (22%). These results confirm that in apple, as in many other plant species, the higher ploidy level of triploids is generally associated with increased sizes of pollen grains, stomata, flowers, fruits and leaves but decreased pollen viability. No clear correlation between ploidy level and flowering time was found. In the case of mixoploid apple genotypes possessing diploid and tetraploid genomes, some phenotype observation is helpful in describing the ploidy level of the histogenic layers, L1 and L2. Small stomata sizes (similar to diploid) indicate diploid L1 and larger leaf sizes, compared to diploid counterparts, show tetraploid L2. The results will be used for breeding, in which it is important to determine maternal and paternal genotypes as well as the direction of the crossing that is of great importance in obtaining seeds and materials for further selection.

scholarly journals Use of Flow Cytometric Measurement of Nuclear DNA Content to Assess Ploidy Level in Azalea

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 627b-627
Author(s):  
Peter H. Velguth ◽  
Harold Pellett
Keyword(s):  
Ploidy Level ◽  
Dna Content ◽  
Nuclear Dna ◽  
Diploid Species ◽  
Nuclear Dna Content ◽  
Chromosome Counts ◽  
Dna Amount ◽  
The North ◽  
Flow Cytometric ◽  
Flow Cytometric Measurement

We evaluated flow cytometric measurement of nuclear DNA content to determine ploidy level in azalea. If ploidy level correlates with DNA content, ploidy level could be determined more readily than by direct chromosome counts and assist in planning crosses and evaluating progeny. Tested plants included azalea cultivars, materials from the azalea breeding project at the Univ. of Minnesota, and species from the Rhododendron Species Botanic Garden and the North Carolina Arboretum. Data compiled from DNA assays of practically all material analyzed fell into distinct groups consistent with their being either diploid, triploid, or tetraploid. Additionally, a known diploid plant of each of four diploid species, together with a natural or derived tetraploid plant of each of these species was obtained. Results showed that the four diploids had a similar DNA content compared to one another. DNA content of the tetraploids was also similar, and the tetraploid's DNA content was approximately twice that of the diploids, as expected. Unfortunately, success with direct chromosome counts in other material has proven elusive, currently precluding direct correlation of DNA amount with ploidy level across other species and cultivars. Although many cases exist in the literature where DNA content has a direct relationship to ploidy level, this does not always hold. Although the majority of plants tested fell into a diploid, triploid, or tetraploid grouping based on DNA content, further study is required to determine the exact relationship between ploidy level and DNA content in azalea.

Taxonomic remarks on the genus Sternbergia L. (Amaryllidaceae) in Turkey based on leaf anatomy, karyosystematic analysis and nuclear DNA content

Phytotaxa ◽  
2016 ◽  
Vol 265 (3) ◽  
pp. 238 ◽  
Author(s):  
MINE KOÇYIĞIT ◽  
METIN TUNA
Keyword(s):  
Content Analysis ◽  
Cross Sections ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Taxonomic Revision ◽  
Chromosome Length ◽  
Data Matrix ◽  
Vascular Bundles ◽  
Taxonomic Markers

Anatomy of leaf cross sections, karyological studies, and nuclear DNA content analysis by flow cytometry were carried out on the six Sternbergia species from Turkey: S. candida (endemic to the country), S. clusiana, S. colchiciflora, S. lutea, S. sicula and S. vernalis. In karyological analysis, number and morphology of the somatic chromosomes, the ploidy level and karyotype formula of the specimens used in the study were investigated in detail. The measurements of somatic chromosomes were calculated with formula of the relative variation in chromosome lenght (CVCL) and mean centromeric asymmetry (MCA). According to the results of this study, there are two different basic chromosome numbers. i.e. x = 10 (S. candida, S. clusiana, S. colchiciflora and S. vernalis) and x = 11 (S. lutea and S. sicula). Results of karyotype analysis corroborated results of previous studies. The smallest chromosome length was measured as 3.05 μm in S. clusiana while the longest length of 20.89 μm was observed in S. sicula. This is the first study reporting nuclear DNA content results for Sternbergia. Based on results of the nuclear DNA content analysis, there is a great variation within the genus in the interspecific level as 2C DNA content varies between 54.03 and 80.42 pg among the species investigated in the study. Anatomical features of the leaves were good taxonomic markers, especially concerning their palisade cells, ribs, cuticle, laticifer canals, vascular bundles, crystals, stomatal index, and stomata structure. Analytical drawings were presented. Six noteworthy leaf characters were quantified, organized in a data matrix, and analysed with UPGMA methods. In conclusion, cytological characteristics of the Sternbergia species together with their leaf features proved to be quite useful in identification and therefore can provide more clarity for taxonomic revision of the genus.

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