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.

Evolution of genome size across some cultivated Allium species

Genome ◽  
2005 ◽  
Vol 48 (3) ◽  
pp. 511-520 ◽  
Author(s):  
A Ricroch ◽  
R Yockteng ◽  
S C Brown ◽  
S Nadot
Keyword(s):  
Flow Cytometry ◽  
Genome Size ◽  
Internal Transcribed Spacer ◽  
Life Form ◽  
Nuclear Dna ◽  
Gc Content ◽  
Nuclear Dna Content ◽  
Dna Amount ◽  
Allium Species ◽  
Nuclear Dna Amount

Allium L. (Alliaceae), a genus of major economic importance, exhibits a great diversity in various morphological characters and particularly in life form, with bulbs and rhizomes. Allium species show variation in several cytogenetic characters such as basic chromosome number, ploidy level, and genome size. The purpose of the present investigation was to study the evolution of nuclear DNA amount, GC content, and life form. A phylogenetic approach was used on a sample of 30 Allium species, including major vegetable crops and their wild allies, belonging to the 3 major subgenera Allium, Amerallium, and Rhizirideum and 14 sections. A phylogeny was constructed using internal transcribed spacer (ITS) sequences of 43 accessions representing 30 species, and the nuclear DNA amount and the GC content of 24 Allium species were investigated by flow cytometry. For the first time, the nuclear DNA content of Allium cyaneum and Allium vavilovii was measured, and the GC content of 16 species was measured. We addressed the following questions: (i) Is the variation in nuclear DNA amount and GC content linked to the evolutionary history of these edible Allium species and their wild relatives? (ii) How did life form (rhizome or bulb) evolve in edible Allium? Our results revealed significant interspecific variation in the nuclear DNA amount as well as in the GC content. No correlation was found between the GC content and the nuclear DNA amount. The reconstruction of nuclear DNA amount on the phylogeny showed a tendency towards a decrease in genome size within the genus. The reconstruction of life form history showed that rhizomes evolved in the subgenus Rhizirideum from an ancestral bulbous life form and were subsequently lost at least twice independently in this subgenus.Key words: Allium, nuclear DNA amount, GC content, flow cytometry, internal transcribed spacer (ITS), phylogeny, life form.

scholarly journals Estimating Nuclear DNA Content in Peach and Related Diploid Species Using Laser Flow Cytometry and DNA Hybridization

1994 ◽  
Vol 119 (6) ◽  
pp. 1312-1316 ◽  
Author(s):  
W. Vance Baird ◽  
Agnes S. Estager ◽  
John K. Wells
Keyword(s):  
Flow Cytometry ◽  
Chromosome Number ◽  
Genome Size ◽  
Dna Content ◽  
Nuclear Dna ◽  
Diploid Species ◽  
Nuclear Genome ◽  
Nuclear Dna Content ◽  
Gene Copy ◽  
Polyploid Series

Using laser flow cytometry, nuclear DNA amounts were estimated for 12 Prunus species, representing three subgenera [Prunophora (Prunus), Amygdalus, and Cerasus (Lithocerasus)], two interspecific hybrids, four cultivars, and a synthetic polyploid series of peach consisting of haploids, diploids, triploids, and tetraploids (periclinal cytochimeras). Peach nuclear DNA content ranged from 0.30 pg for the haploid nuclei to 1.23 pg for the tetraploid nuclei. The diploid genome of peach is relatively small and was estimated to be 0.60±0.03 pg (or 5.8×108 nucleotide base pairs). The polyploid series represented the expected arithmetic progression, as genome size positively correlated with ploidy level (i.e., DNA content was proportional to chromosome number). The DNA content for the 12 diploid species and two interspecific diploid hybrids ranged from 0.57 to 0.79 pg. Genome size estimates were verified independently by Southern blot analysis, using restriction fragment length polymorphism clones as gene-copy equivalents. Thus, a relatively small and stable nuclear genome typifies the Prunus species investigated, consistent with their low, basic chromosome number (× = 8).

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.

Genome size in 21 Artemisia L. species (Asteraceae, Anthemideae): Systematic, evolutionary, and ecological implications

Genome ◽  
2001 ◽  
Vol 44 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Montserrat Torrell ◽  
Joan Vallès
Keyword(s):  
Flow Cytometry ◽  
Genome Size ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Life Forms ◽  
Dna Amount ◽  
Ploidy Levels ◽  
Ecological Selection ◽  
Ecological Implications

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.

scholarly journals Miscanthus: Inter- and Intraspecific Genome Size Variation Among M. × Giganteus, M. Sinensis, M. Sacchariflorus Accessions

2015 ◽  
Vol 57 (1) ◽  
pp. 104-113
Author(s):  
Sandra Cichorz ◽  
Maria Gośka ◽  
Monika Rewers
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Nuclear Dna ◽  
Size Variation ◽  
Nuclear Dna Content ◽  
Interspecific Variation ◽  
Genome Size Variation ◽  
2C Dna Content ◽  
Cytological Characteristics ◽  
Stomatal Length

AbstractSinceM. sinensisAnderss.,M. sacchariflorus(Maxim.) Hack. andM. ×giganteusJ.M.Greef & Deuter ex Hodk. and Renvoize have considerably the highest potential for biomass production amongMiscanthusAnderss. species, there is an urgent need to broaden the knowledge about cytological characteristics required for their improvement. In this study our objectives were to assess the genome size variation among eighteenMiscanthusaccessions, as well as estimation of the monoploid genome size (2C and Cx) of theM. sinensiscultivars, which have not been analyzed yet. The characterization of threeMiscanthusspecies was performed with the use of flow cytometry and analysis of the stomatal length. The triploid (2n = 3x = 57)M. sinensis‘Goliath’ andM. ×giganteusclones possessed the highest 2C DNA content (8.34 pg and 7.43 pg, respectively). The intermediate 2C-values were found in the nuclei of the diploid (2n = 2x = 38)M. sinensisaccessions (5.52–5.72 pg), whereas they were the lowest in the diploid (2n = 2x = 38)M. sacchariflorusecotypes (4.58–4.59 pg). The presented study revealed interspecific variation of nuclear DNA content (P<0.01) and therefore allowed for recognition of particular taxa, inter- and intraspecific hybrids and prediction of potential parental components. Moreover, intraspecific genome size variation (P<0.01) was observed inM. sinensiscultivars at 3.62%. The values of the stomatal size obtained for the triploidM. ×giganteus‘Great Britain’ (mean 30.70 μm) or ‘Canada’ (mean 29.67 μm) and diploidM. sinensis‘Graziella’ (mean 29.96 μm) did not differ significantly, therefore this parameter is not recommended for ploidy estimation.

C-banding and DNA content in seven species of Tenebrionidae (Coleoptera)

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 834-839 ◽  
Author(s):  
C. Juan ◽  
E. Petitpierre
Keyword(s):  
Genome Size ◽  
X Chromosome ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
C Banding ◽  
Metaphase I

The relative amount of C-banded heterochromatin varies strikingly in seven species of tenebrionid beetles, from 25 to 58%, but most species show procentric bands only. Nevertheless, Gonocephalum patruele exhibits an almost completely heterochromatic X chromosome. The nuclear DNA content of Feulgen-stained spermatids has yielded up to a threefold difference, from 0.27 to 0.86 pg, which is not completely in accordance with the amount of C-banded heterochromatin. However, the genome sizes correlate significantly with the total chromosome areas at metaphase I and with the spermatid areas. Furthermore, the genome sizes agree with the subfamilial taxonomic groupings of these tenebrionids.Key words: Tenebrionidae, genome size, C-banding.

scholarly journals Intraspecific variation in nuclear DNA content in Collinsia verna nutt. (Scrophulariaceae)

Heredity ◽  
1984 ◽  
Vol 52 (2) ◽  
pp. 235-242 ◽  
Author(s):  
Judith K Greenlee ◽  
K S Rai ◽  
Alton D Floyd
Keyword(s):  
Intraspecific Variation ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Collinsia Verna

DNA–Feulgen cytophotometric determination of genome size for the freshwater-invading copepod Eurytemora affinis

Genome ◽  
2004 ◽  
Vol 47 (3) ◽  
pp. 559-564 ◽  
Author(s):  
Ellen M Rasch ◽  
Carol Eunmi Lee ◽  
Grace A Wyngaard
Keyword(s):  
Somatic Cell ◽  
Genome Size ◽  
Dna Content ◽  
Nuclear Dna ◽  
Growth Characteristic ◽  
Nuclear Dna Content ◽  
Cell Nuclei ◽  
Chromatin Diminution ◽  
Eurytemora Affinis ◽  
Genomic Studies

Variation in nuclear DNA content within some eukaryotic species is well documented, but causes and consequences of such variation remain unclear. Here we report genome size of an estuarine and salt-marsh calanoid copepod, Eurytemora affinis, which has recently invaded inland freshwater habitats independently and repeatedly in North America, Europe, and Asia. Adults and embryos of E. affinis from the St. Lawrence River drainage were examined for somatic cell DNA content and the presence or absence of embryonic chromatin diminution, using Feulgen–DNA cytophotometry to determine a diploid or 2C genome size of 0.6–0.7 pg DNA/cell. The majority of somatic cell nuclei, however, have twice this DNA content (1.3 pg/nucleus) in all of the adults examined and possibly represent a population of cells arrested at the G2 stage of the cell cycle or associated with some degree of endopolyploidy. Both suggestions contradict assumptions that DNA replication does not occur in adult tissues during the determinate growth characteristic of copepods. Absence of germ cell nuclei with markedly elevated DNA values, commonly found for species of cyclopoid copepods that show chromatin diminution, indicates that E. affinis lacks this trait. The small genome size and presumed absence of chromatin diminution increase the potential utility of E. affinis as a model for genomic studies on mechanisms of adaptation during freshwater invasions.Key words: copepod, genome size, DNA–Feulgen, calanoid, Eurytemora.

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