Nuclear DNA content in the Australian Bulbine (Liliaceae)

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 225-234 ◽  
Author(s):  
E. M. Watson

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.

1983 ◽  
Vol 29 (9) ◽  
pp. 1179-1183 ◽  
Author(s):  
A. L. Franklin ◽  
W. G. Filion ◽  
J. B. Anderson

Armillaria mellea, a phytopathogenic fungus, is the only member of the Agaricales (Basidiomycetes) whose fertile vegetative phase in nature is thought to be diploid, rather than dikaryotic. To examine the vegetative ploidy of A. mellea, we used the DNA-binding antibiotic, mithramycin, for fluorometry of in situ nuclear DNA. The measurements of nuclear DNA content indicated that strains derived from single basidiospores of A. mellea were haploid and that strains derived from matings of isolates of single spores were diploid. These data confirm the results of earlier genetic experiments, which show haploidy and diploidy in unmated and mated strains, respectively. Nuclear DNA measurements in known haploid and diploid strains of Aspergillus nidulans confirmed the validity of our protocol.


Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 659-662 ◽  
Author(s):  
H. L. Porter ◽  
A. Lane Rayburn

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.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 580e-580
Author(s):  
Rodomiro Ortiz ◽  
D.E. Costich ◽  
T.P. Meagher ◽  
N. Vorsa

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 ◽  
2007 ◽  
Vol 50 (11) ◽  
pp. 1029-1037 ◽  
Author(s):  
T. Eilam ◽  
Y. Anikster ◽  
E. Millet ◽  
J. Manisterski ◽  
O. Sagi-Assif ◽  
...  

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.


Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 825-834 ◽  
Author(s):  
S. Essad

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]


2016 ◽  
Vol 58 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Małgorzata Podwyszyńska ◽  
Dorota Kruczyńska ◽  
Aleksandra Machlańska ◽  
Barbara Dyki ◽  
Iwona Sowik

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.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 627b-627
Author(s):  
Peter H. Velguth ◽  
Harold Pellett

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.


1998 ◽  
Vol 21 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Margarida Lima Carvalho ◽  
Claudio Oliveira ◽  
Fausto Foresti

The present paper reports nuclear DNA content in 30 Neotropical freshwater fish species and summarizes the data on other Neotropical species presented in the literature. Among Neotropical fishes, the nuclear DNA content ranges from 1.04 ± 0.09 pg/nucleus in Corydoras cf. simulatus (2n = 62) to 248.0 pg/nucleus in Lepidosiren paradoxa (2n = 38). A general analysis of the data obtained in the present study for each species showed that DNA measurements were practically constant at the individual level, while significant differences were observed among individuals of the same population. This observation was valid for all species analyzed and was more evident in those species that presented other karyotypic particularities such as sex chromosomes or supernumerary chromosomes. The importance of changes in nuclear DNA content in the evolutionary process of Neotropical fishes is discussed.


Genome ◽  
2001 ◽  
Vol 44 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Montserrat Torrell ◽  
Joan Vallès

Genome size was estimated by flow cytometry in 24 populations belonging to 22 Artemisia taxa (21 species, 1 with two subspecies), which represent the distinct subgenera, life forms, basic chromosome numbers, and ploidy levels in the genus. 2C nuclear DNA content values range from 3.5 to 25.65 pg, which represents a more than sevenfold variation. DNA content per haploid genome ranges from 1.75 to 5.76 pg. DNA amount is very well correlated with karyotype length and ploidy level. Some variations in genome size have systematic and evolutionary implications, whereas others are linked to ecological selection pressures.Key words: Artemisia, Asteraceae, flow cytometry, genome size, nuclear DNA amount variation, systematics, evolution, ecology.


Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 143-147 ◽  
Author(s):  
Jayanti Sen ◽  
Sumona Mukherjee ◽  
A. K. Sharma

Cells of six different species of Luzula were subjected to in vitro culture and examined for callus formation. The cells of calli from the different species were analyzed for variation in chromosome number. The cells of different species showed a differential response in culture with respect to callus growth. Chromosome number variation in vitro, including both hypo- and hyper-diploidy, was recorded in all species except L. pediformis and L. luzuloides. The chromosome fragments survived as a result of a nonlocalized centromere. With prolonged culture, normal diploid cells were frequent. The nuclear DNA content of cells of these species was also measured, both in vivo and in vitro. The DNA values ranged from 6.05 to 7.03 pg per 4C nucleus. No marked change in DNA value was noted in cells even with high chromosome numbers, thereby confirming their origin through fragmentation of chromosomes. In cells of callus, the DNA amount was observed to be higher than in normal cells, indicating fragmentation and duplication of individual chromosomes. Their importance in the origin of new genotypes has been indicated.Key words: Luzula spp., in vitro growth, chromosomes, nuclear DNA content.


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