scholarly journals Polyploidy and genome size variation in Phlox nana (Polemoniaceae) from the Pecos plains of New Mexico and the Davis Mountains of West Texas

2017 ◽  
Vol 11 (2) ◽  
pp. 351-362
Author(s):  
Jamie Ladner ◽  
Mark H. Mayfield ◽  
L. Alan Prather ◽  
Carolyn J. Ferguson
Keyword(s):  
New Mexico ◽  
Genome Size ◽  
Size Variation ◽  
Chromosome Counts ◽  
Genome Size Variation ◽  
Ploidy Levels ◽  
West Texas ◽  
Popula Tions ◽  
Davis Mountains ◽  
Parapatric Distribution

Polyploidy is conspicuous in the genus Phlox, and some species exhibit variation in ploidy levels, or cytotypic variation. Diploid, tetraploid and hexaploid popula-tions of P. nana occur across parts of the species distribution in the southwestern United States and northern Mexico. A recent study highlighted two areas for which ploidy level inferences were challenging: a population on the Pecos Plains of New Mexico (“Caprock”) and the Davis Mountains region of West Texas. Plants in these areas were sampled and chromosome counts and flow cytometry methods were used to assess ploidy levels and genome sizes. Homoploid variation in ge-nome size was unambiguously documented: the genome size of tetraploid plants from the Davis Mountains was significantly larger than that of plants from Caprock. The general condition of larger genome sizes for plants in the Davis Mountains explains previous difficulty in determining ploidy levels within the region. Most plants at the Caprock population appeared to be tetraploid (2n=28), but chromosome counts revealed variants, including some putative pentaploids. Within the Davis Mountains region, both diploid (2n=14) and tetraploid (2n=28) cytotypes were documented, with a parapatric distribution. Overall, this study clarifies patterns of cytotypic diversity in P. nana, highlights an example of infraspecific, homoploid genome size variation, and contributes to a framework for ongoing evolutionary investigation in this study system.

scholarly journals Genome size variation and karyotype diversity in eight taxa of Sorbus sensu stricto (Rosaceae) from China

2021 ◽  
Vol 15 (2) ◽  
pp. 137-148
Author(s):  
Jiabao Li ◽  
Kailin Zhu ◽  
Qin Wang ◽  
Xin Chen
Keyword(s):  
Flow Cytometry ◽  
Genome Size ◽  
Size Variation ◽  
Sensu Stricto ◽  
Chromosome Size ◽  
Chromosome Counting ◽  
Genome Size Variation ◽  
Ploidy Levels ◽  
First Time ◽  
Karyotype Symmetry

Eight taxa of Sorbus Linnaeus, 1753 sensu stricto (Rosaceae) from China have been studied karyologically through chromosome counting, chromosomal measurement and karyotype symmetry. Genome size was also estimated by flow cytometry. Six taxa, S. amabilis Cheng ex T.T.Yu et K.C.Kuan, 1963, S. hupehensis var. paucijuga (D.K. Zang et P.C. Huang, 1992) L.T. Lu, 2000, S. koehneana C.K. Schneider, 1906, S. pohuashanensis (Hance, 1875) Hedlund, 1901, S. scalaris Koehne, 1913 and S. wilsoniana C.K. Schneider, 1906 are diploids with 2n = 34, whereas two taxa, S. filipes Handel-Mazzetti,1933 and S. ovalis McAllister, 2005 are tetraploid with 2n = 68. In general, the chromosome size is mainly small, and karyotypes are symmetrical with predominance of metacentric chromosomes. Genome size variation of diploids and tetraploids is 1.401 pg –1.676 pg and 2.674 pg –2.684 pg, respectively. Chromosome numbers of S. amabilis and S. hupehensis var. paucijuga, and karyotype and genome size of eight taxa studied are reported for the first time. This study emphasised the reliability of flow cytometry in genome size determination to infer ploidy levels in Chinese native Sorbus species.

scholarly journals Genome Size and Ploidy of Phlox paniculata and Related Germplasm in Subsections Paniculatae and Phlox

2015 ◽  
Vol 140 (5) ◽  
pp. 436-448 ◽  
Author(s):  
Peter J. Zale ◽  
Pablo Jourdan
Keyword(s):  
Genome Size ◽  
Ornamental Plants ◽  
Size Variation ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Triploid Hybrid ◽  
Chromosome Counts ◽  
Ploidy Levels ◽  
First Report ◽  
Phlox Paniculata

Phlox is an important genus of herbaceous ornamental plants previously targeted for germplasm development, characterization, and enhancement by the U.S. Department of Agriculture, National Plant Germplasm System. Among Phlox in cultivation, Phlox paniculata is the most widely grown and intensively bred species, but little is known about variation in genome size and ploidy of this species or of related taxa that may be used for germplasm enhancement. The objective of this study was to assess cytotype variation in a diverse collection of cultivars and wild germplasm of P. paniculata (subsection Paniculatae) and of related taxa in subsections Paniculatae and Phlox. The collection included 138 accessions from seven species and two interspecific hybrids. Flow cytometry was used to estimate holoploid (2C) genome sizes and to infer ploidy levels. Chromosome counts were made to calibrate ploidy with genome size for a subset of taxa. Most cultivars were diploid (2n = 2x = 14) and had mean genome sizes that did not vary between subsections Paniculatae (14.33 pg) and Phlox (14.23 pg) although size variation was greater among cultivars within subsection Phlox. Triploid cultivars of P. paniculata, with a mean genome size of 21.36 pg and mitotic chromosome counts of 2n = 3x = 21, were identified. Such triploids suggests previous interploid hybridization within this taxon. Five tetraploid (2n = 4x = 28) cultivars were found in subsection Phlox; all were selections of P. glaberrima ssp. triflora, and had a mean genome size of 25.44 pg; chromosome counts in one of these confirmed they were tetraploid. The putative hybrid Phlox Suffruticosa Group ‘Miss Lingard’ showed an intermediate genome size of 21.21 pg supporting a triploid, hybrid origin of this taxon. Mean 2C genome sizes among wild-collected accessions were similar to values reported for cultivars (Paniculatae = 14.59 pg, Phlox = 14.23 pg), but taxa in subsection Phlox exhibited greater variation that included two tetraploids identified among wild-collected accessions; one, of P. pulchra, had a mean genome size of 26.17 pg, representing the first report of polyploidy in the taxon. This is the first report on genome size for the majority of species in the study. Although genome size could not be used to differentiate taxa in subsections Paniculatae and Phlox, the data provide further insights into cytotype variation of Phlox germplasm useful for plant breeders and systematists.

scholarly journals Genome Size and Ploidy Levels of Cercis (Redbud) Species, Cultivars, and Botanical Varieties

HortScience ◽  
2016 ◽  
Vol 51 (4) ◽  
pp. 330-333 ◽  
Author(s):  
David J. Roberts ◽  
Dennis J. Werner
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Internal Standard ◽  
Close Relative ◽  
Genome Size Variation ◽  
Ploidy Levels ◽  
Wide Range ◽  
Average Size ◽  
Size Estimates ◽  
Botanical Varieties

Cercis is an ancient member of Fabaceae, often cultivated as an ornamental tree, and can be found in numerous regions around the world. Previous studies have reported Cercis canadensis as being diploid with 2n = 2x = 14. However, there have been no further investigations into ploidy and genome size variation among Cercis taxa. A study was conducted to evaluate the relative genome size and ploidy levels of numerous species, cultivars, and botanical varieties of Cercis, representing taxa found in North America, Asia, and the Middle East. In addition, the genome size of Bauhinia forficata, a close relative of Cercis, was also determined. Genome size estimates (2C values) were determined by calculating the mean fluorescence of stained nuclei via flow cytometry. Propidium iodide was used as the staining agent and Glycine max was used as an internal standard for each taxon analyzed. Genome size estimates for all Cercis sampled ranged from 0.70 to 0.81 pg with an average size of 0.75 pg. The genome size of B. forficata was found to be smaller than any other Bauhinia sp. currently on record, with an average size of 0.87 pg. This study confirmed an initial estimation of the genome size of Cercis chinensis and found that floral buds of Cercis proved to be an excellent source of plant tissue for obtaining intact nuclei. All species, botanical varieties, and cultivars of Cercis surveyed for this study had remarkably similar genome sizes despite their wide range of distribution. This information can facilitate a better understanding of phylogenetic relationships within Cercideae and Cercis specifically.

scholarly journals Genome size variation in Deschampsia cespitosa sensu lato (Poaceae) in Eurasia

2022 ◽  
Vol 308 (1) ◽  
Author(s):  
Josef Greimler ◽  
Eva M. Temsch ◽  
Zhiqing Xue ◽  
Hanna Weiss-Schneeweiss ◽  
Polina Volkova ◽  
...  
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Genome Size Variation ◽  
Geographic Scale ◽  
Reproduction Mode ◽  
Ploidy Levels ◽  
Deschampsia Cespitosa ◽  
Flow Cytometric ◽  
Significant Difference ◽  
Disturbed Habitats

AbstractThe grass Deschampsia cespitosa is a variable taxon out of which many varieties, subspecies and endemic species have been separated. In this paper, the variation in genome size (GS) and ploidy of this grass including several of its subspecies and two related species in Eurasia was investigated by flow cytometric (FCM) measurements. GS and ploidy data were also related to specific environments and reproduction mode. Ploidy levels found by FCM were confirmed by chromosome counts of diploid (2n = 28) and tetraploid (2n = 52) samples. Seminiferous (seed bearing) D. cespitosa was mainly diploid (GS between 3.754 and 5.438 pg/1C). GS variation in diploids showed a geographic pattern with a significant difference (H = 41,441, P < 0.001) between European (median = 4.377 pg) and Asian (median = 4.881 pg) accessions. Genome size (1C) in tetraploids ranged from 7.9426 to 9.0399 pg. Tetraploid seminiferous D. cespitosa was found mostly in disturbed habitats in western and southern Europe, while tetraploids in Asia were registered in wet Arctic habitats. Genome size (1C between 8.3278 and 8.8603 pg) of the pseudoviviparous plants (spikelets produce plantlets asexually) of wet habitats in central and northern Europe indicated tetraploidy. A putative triploid (GS 6.6817 pg) was detected in Iceland. Summing up, we found a high variation in GS on the geographic scale with significant regional differences in diploid D. cespitosa. Among the tetraploids, the asexually reproducing plants were bound to specific habitats, while the seminiferous plants showed a habitat preference similar to the diploids.

scholarly journals Ploidy tug-of-war: evolutionary and genetic environments influence the rate of ploidy drive in a human fungal pathogen

2016 ◽  
Author(s):  
Aleeza C. Gerstein ◽  
Heekyung Lim ◽  
Judith Berman ◽  
Meleah A. Hickman
Keyword(s):  
Genome Size ◽  
Fungal Pathogen ◽  
Size Variation ◽  
Nuclear Genome ◽  
Complete Medium ◽  
Genome Size Variation ◽  
Ploidy Levels ◽  
Human Fungal Pathogen ◽  
Original Genome ◽  
Phosphorus Depletion

AbstractVariation in baseline ploidy is seen throughout the tree of life, yet the factors that determine why one ploidy level is selected over another remain poorly understood. Experimental evolution studies using asexual fungal microbes with manipulated ploidy levels intriguingly reveals a propensity to return to the historical baseline ploidy, a phenomenon that we term ‘ploidy drive’. We evolved haploid, diploid, and polyploid strains of the human fungal pathogen Candida albicans under three different nutrient limitation environments to test whether these conditions, hypothesized to select for low ploidy levels, could counteract ploidy drive. Strains generally maintained or acquired smaller genome sizes in minimal medium and under phosphorus depletion compared to in a complete medium, while mostly maintained or acquired increased genome sizes under nitrogen depletion. Surprisingly, improvements in fitness often ran counter to changes in total nuclear genome size; in a number of scenarios lines that maintained their original genome size often increased in fitness more than lines that converged towards diploidy. Combined, this work demonstrates a role for both the environment and genotype in determination of the rate of ploidy drive, and highlights questions that remain about the force(s) that cause genome size variation.

scholarly journals Genome size variation and karyotype diversity in eight taxa of Sorbus sensu stricto (Rosaceae) from China

2021 ◽  
Vol 15 (2) ◽  
pp. 137-148
Author(s):  
Jiabao Li ◽  
Kailin Zhu ◽  
Qin Wang ◽  
Xin Chen
Keyword(s):  
Flow Cytometry ◽  
Genome Size ◽  
Size Variation ◽  
Sensu Stricto ◽  
Chromosome Size ◽  
Chromosome Counting ◽  
Genome Size Variation ◽  
Ploidy Levels ◽  
First Time ◽  
Karyotype Symmetry

Eight taxa of Sorbus Linnaeus, 1753 sensu stricto (Rosaceae) from China have been studied karyologically through chromosome counting, chromosomal measurement and karyotype symmetry. Genome size was also estimated by flow cytometry. Six taxa, S. amabilis Cheng ex T.T.Yu et K.C.Kuan, 1963, S. hupehensis var. paucijuga (D.K. Zang et P.C. Huang, 1992) L.T. Lu, 2000, S. koehneana C.K. Schneider, 1906, S. pohuashanensis (Hance, 1875) Hedlund, 1901, S. scalaris Koehne, 1913 and S. wilsoniana C.K. Schneider, 1906 are diploids with 2n = 34, whereas two taxa, S. filipes Handel-Mazzetti,1933 and S. ovalis McAllister, 2005 are tetraploid with 2n = 68. In general, the chromosome size is mainly small, and karyotypes are symmetrical with predominance of metacentric chromosomes. Genome size variation of diploids and tetraploids is 1.401 pg –1.676 pg and 2.674 pg –2.684 pg, respectively. Chromosome numbers of S. amabilis and S. hupehensis var. paucijuga, and karyotype and genome size of eight taxa studied are reported for the first time. This study emphasised the reliability of flow cytometry in genome size determination to infer ploidy levels in Chinese native Sorbus species.

scholarly journals Genomes Vary in Size and Spatial Patterns Within Chimeric Blades of Porphyra spp.

2021 ◽  
Vol 8 ◽  
Author(s):  
Elena Varela-Álvarez ◽  
João Loureiro ◽  
Patrick G. Meirmans ◽  
Mariana Castro ◽  
Ester A. Serrão
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Life Time ◽  
Single Individual ◽  
Genome Size Variation ◽  
Individual Organism ◽  
Ploidy Levels ◽  
Genome Duplications ◽  
Red Algal ◽  
Species Groups

Genome size variation is of crucial biological importance, however variation in genome sizes within a single individual/organism is rarely reported except for some species groups such as algae where polygenomy, endopolyploidy and mixopolyploidy have previously been reported. The red algal genus Porphyra forms part of very profitable marine food products commonly known as ‘Nori’. Farming of these valuable marine crops was revolutionized by the discovery of their life cycle in the 40’s. One of the most remarkable characteristics of these taxa is the formation of chimeric gametophytic thalli. After meiosis, the four meiotic products are not released as individuals spores, but instead develop together into a single leafy thallus through successive mitotic divisions. In this study, we used flow cytometry to estimate genome sizes in 670 vegetative thallus sections from 195 blades from three Porphyra species, to determine if this chimerism could be related to the presence of multiple genome sizes and mixoploidy within thalli. Our results show a wide variety of genome sizes both within and between thalli. We interpreted these results as the presence of two different genome types of different sizes (a and b) with separate rounds of genome duplications within the vegetative thalli. By analyzing several sections per thallus, we were able to show that the different genome types and ploidy levels are not distributed haphazardly through the thallus, but are distributed along the thallus in a sectorial way in mosaics. In some individuals, the 2C genome size can either be interpreted as diploids or alternatively as haploid cells that are arrested at the G2-stage of the mitotic cycle, acting as diploid with two copies of their genome during most of their life-time. We conclude that Porphyra species belong to an aneuploid/euploid system, where genome duplications, mixoploidy, chromosomal dynamics and the presence of different genome types in the chimeric thalli play a role in shaping the genetic diversity of these taxa. Our results may have important implications to understand red algae biology and evolution and raise further questions on concepts of what constitutes an individual.

Documenting Intraspecfic Genome Size Variation in Soybean

Crop Science ◽  
2004 ◽  
Vol 44 (1) ◽  
pp. 261 ◽  
Author(s):  
A. Lane Rayburn ◽  
D. P. Biradar ◽  
R. L. Nelson ◽  
R. McCloskey ◽  
K. M. Yeater
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Genome Size Variation

scholarly journals Genome size variation in deep-sea amphipods

2017 ◽  
Vol 4 (9) ◽  
pp. 170862 ◽  
Author(s):  
H. Ritchie ◽  
A. J. Jamieson ◽  
S. B. Piertney
Keyword(s):  
Life History ◽  
Genome Size ◽  
Deep Sea ◽  
Research Effort ◽  
Life History Strategy ◽  
Size Variation ◽  
Genome Size Variation ◽  
New Hebrides ◽  
Contrast Analysis ◽  
Independent Contrast

Genome size varies considerably across taxa, and extensive research effort has gone into understanding whether variation can be explained by differences in key ecological and life-history traits among species. The extreme environmental conditions that characterize the deep sea have been hypothesized to promote large genome sizes in eukaryotes. Here we test this supposition by examining genome sizes among 13 species of deep-sea amphipods from the Mariana, Kermadec and New Hebrides trenches. Genome sizes were estimated using flow cytometry and found to vary nine-fold, ranging from 4.06 pg (4.04 Gb) in Paralicella caperesca to 34.79 pg (34.02 Gb) in Alicella gigantea . Phylogenetic independent contrast analysis identified a relationship between genome size and maximum body size, though this was largely driven by those species that display size gigantism. There was a distinct shift in the genome size trait diversification rate in the supergiant amphipod A. gigantea relative to the rest of the group. The variation in genome size observed is striking and argues against genome size being driven by a common evolutionary history, ecological niche and life-history strategy in deep-sea amphipods.

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