scholarly journals How small and constrained is the genome size of angiosperm woody species

2015 ◽  
Vol 64 (1-6) ◽  
pp. 20-32 ◽  
Author(s):  
Deepak Ohri
Keyword(s):  
Genome Size ◽  
Cell Size ◽  
Large Population ◽  
Size Variation ◽  
Woody Species ◽  
Herbaceous Species ◽  
Wood Fibers ◽  
Genome Size Variation ◽  
Woody Habit ◽  
Taxonomic Groups

AbstractAngiosperm hardwood species are generally considered to show an average smaller genome size with a narrow range of variation than their herbaceous counterparts. Various explanations pertaining to limitations of cell size exerted by wood fibers, the requirement of smaller stomata, longer generation time, large population size, etc., have been put forward to account for their small and constrained genome size. Yet studies done in the past several years show that genomically as well as evolutionarily, hardwoods are as diverse and active as their herbaceous counterparts. This is entirely supported by the presence of well developed inter and intraspecific polyploid series and natural triploidy in many genera. Polyploidy, in some instances has been shown to confer adaptability to arid and salt stress conditions and in colonization of new areas. Moreover, hardwoods also show reasonable amenability to the induced polyploidy which abruptly changes the balance between nuclear and cell size. Polyploidy has been induced in many hardwoods to restore fertility in interspecific hybrids and for the production of triploids.Furthermore, some cases studied show that genome size variation in hardwoods can be as variable as that of herbaceous species. Genome size has been shown to vary remarkably both at homoploid level as well as by polyploidy in certain genera. In the same way, the genome size is not correlated with the habit in certain groups having both herbaceous and woody taxa. This point is further proved by the presence of secondary and insular woody habit in certain cases where either the transition to woodiness is not followed by any diminution in the genome size, or the genome size of insular woody species may be even more than that of the congeneric herbaceous species. This shows that woody habit does not by itself put any constraints on the genome size either at homoploid or at polyploidy levels. The genome size in fact, not only varies significantly in many congeneric woody species but also may not show any correlation with the habit when woody and herbaceous species are compared in some narrow taxonomic groups studied.

scholarly journals Substantial intraspecific genome size variation in golden-brown algae and its phenotypic consequences

2020 ◽  
Vol 126 (6) ◽  
pp. 1077-1087
Author(s):  
Dora Čertnerová ◽  
Pavel Škaloud
Keyword(s):  
Growth Rate ◽  
Genome Size ◽  
Cell Size ◽  
Nuclear Dna ◽  
Gc Content ◽  
Size Variation ◽  
Nuclear Dna Content ◽  
Genome Size Variation ◽  
Adaptive Consequences ◽  
Genomic Gc Content

Abstract Background and Aims While nuclear DNA content variation and its phenotypic consequences have been well described for animals, vascular plants and macroalgae, much less about this topic is known regarding unicellular algae and protists in general. The dearth of data is especially pronounced when it comes to intraspecific genome size variation. This study attempts to investigate the extent of intraspecific variability in genome size and its adaptive consequences in a microalgal species. Methods Propidium iodide flow cytometry was used to estimate the absolute genome size of 131 strains (isolates) of the golden-brown alga Synura petersenii (Chrysophyceae, Stramenopiles), identified by identical internal transcribed spacer (ITS) rDNA barcodes. Cell size, growth rate and genomic GC content were further assessed on a sub-set of strains. Geographic location of 67 sampling sites across the Northern hemisphere was used to extract climatic database data and to evaluate the ecogeographical distribution of genome size diversity. Key Results Genome size ranged continuously from 0.97 to 2.02 pg of DNA across the investigated strains. The genome size was positively associated with cell size and negatively associated with growth rate. Bioclim variables were not correlated with genome size variation. No clear trends in the geographical distribution of strains of a particular genome size were detected, and strains of different genome size occasionally coexisted at the same locality. Genomic GC content was significantly associated only with genome size via a quadratic relationship. Conclusions Genome size variability in S. petersenii was probably triggered by an evolutionary mechanism operating via gradual changes in genome size accompanied by changes in genomic GC content, such as, for example, proliferation of transposable elements. The variation was reflected in cell size and relative growth rate, possibly with adaptive consequences.

The nucleotypic effects of cellular DNA content in cartilaginous and ray-finned fishes

Genome ◽  
2003 ◽  
Vol 46 (4) ◽  
pp. 683-706 ◽  
Author(s):  
David C Hardie ◽  
Paul D.N Hebert
Keyword(s):  
Genome Size ◽  
Cell Size ◽  
Dna Content ◽  
Significant Positive Correlation ◽  
Cold Water ◽  
Size Variation ◽  
Nucleus Size ◽  
Genome Size Variation ◽  
Cartilaginous Fishes ◽  
Cellular Dna

Cytological and organismal characteristics associated with cellular DNA content underpin most adaptionist interpretations of genome size variation. Since fishes are the only group of vertebrate for which relationships between genome size and key cellular parameters are uncertain, the cytological correlates of genome size were examined in this group. The cell and nuclear areas of erythrocytes showed a highly significant positive correlation with each other and with genome size across 22 cartilaginous and 201 ray-finned fishes. Regressions remained significant at all taxonomic levels, as well as among different fish lineages. However, the results revealed that cartilaginous fishes possess higher cytogenomic ratios than ray-finned fishes, as do cold-water fishes relative to their warm-water counterparts. Increases in genome size owing to ploidy shifts were found to influence cell and nucleus size in an immediate and causative manner, an effect that persists in ancient polyploid lineages. These correlations with cytological parameters known to have important influences on organismal phenotypes support an adaptive interpretation for genome size variation in fishes.Key words: evolution, genome size, DNA content, cell size, erythrocyte size, fishes, nucleotypic effect.

Genome Size in South American Gentianella (Gentianaceae, Swertiinae), with a Special Emphasis on Species from the Bolivian and Ecuadorian Andes

2021 ◽  
Vol 106 ◽  
pp. 31-46
Author(s):  
Simon Pfanzelt ◽  
Jan Ptáček ◽  
Petr Sklenář ◽  
K. Bernhard Von Hagen ◽  
Dirk C. Albach
Keyword(s):  
South America ◽  
Genome Size ◽  
Size Variation ◽  
Corolla Tube ◽  
Comprehensive Treatment ◽  
Mean Annual Temperature ◽  
South American ◽  
Genome Size Variation ◽  
Temperature And Precipitation ◽  
Taxonomic Groups

The subcosmopolitan genus Gentianella Moench (Gentianaceae, Swertiinae), with more than 170 currently accepted species in South America alone, is one of the emblematic examples of major and rapid radiations in the Andes. However, the taxonomy of South American Gentianella is far from being resolved. Over a century has passed since the publication of the last comprehensive treatment by Ernst Gilg in 1916. Using flow cytometry, the genome size of 115 accessions of 39 species, of which 37 were from South America, was measured, with the objective to assess the taxonomic utility of that trait. Also, the relationships of genome size with environmental factors such as mean annual temperature and precipitation, as well as the life history traits, habit, reproduction, habitat, and elevational belt were examined. The genome size values of the investigated South American accessions fell into two size classes, ranging from 2C = 7.60 pg to 11.30 pg and from 2C = 16.54 pg to 18.34 pg. The latter size class contained only accessions of G. briquetiana (Gilg) T. N. Ho & S. W. Liu. These accessions, and a further one of G. limoselloides (Kunth) Fabris with an intermediate value of 2C = 14.71 pg, were inferred to be octoploid. Genome size was not correlated with temperature, precipitation, habit, or elevational belt. By contrast, significant differences in genome size between groups were found regarding habitat and reproduction. Furthermore, genome size of one of the informal taxonomic groups of Gilg (Barbatae) differed from that of the remaining groups. However, this finding is of doubtful taxonomic relevance because of inconsistencies in the application of Gilg’s defining criterion of Barbatae, i.e., the presence of trichomes inside the corolla tube. Based on the overall results, it is concluded that genome size is not a taxonomically useful trait in South American Gentianella. Still, the data offer a first view on genome size variation and evolution in this diverse but poorly studied group.

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.

scholarly journals Patterns of genome size variation in snapping shrimp

Genome ◽  
2016 ◽  
Vol 59 (6) ◽  
pp. 393-402 ◽  
Author(s):  
Nicholas W. Jeffery ◽  
Kristin Hultgren ◽  
Solomon Tin Chi Chak ◽  
T. Ryan Gregory ◽  
Dustin R. Rubenstein
Keyword(s):  
Genome Size ◽  
Phylogenetic Signal ◽  
Size Variation ◽  
Diverse Group ◽  
Chromosome Size ◽  
Genome Size Variation ◽  
Large Genome ◽  
Large Genome Size ◽  
Single Genus ◽  
Geographic Regions

Although crustaceans vary extensively in genome size, little is known about how genome size may affect the ecology and evolution of species in this diverse group, in part due to the lack of large genome size datasets. Here we investigate interspecific, intraspecific, and intracolony variation in genome size in 39 species of Synalpheus shrimps, representing one of the largest genome size datasets for a single genus within crustaceans. We find that genome size ranges approximately 4-fold across Synalpheus with little phylogenetic signal, and is not related to body size. In a subset of these species, genome size is related to chromosome size, but not to chromosome number, suggesting that despite large genomes, these species are not polyploid. Interestingly, there appears to be 35% intraspecific genome size variation in Synalpheus idios among geographic regions, and up to 30% variation in Synalpheus duffyi genome size within the same colony.

scholarly journals Genome size variation in gymnosperms under different growth conditions

Caryologia ◽  
2015 ◽  
Vol 68 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Oriane Hidalgo ◽  
Joan Vallès ◽  
Angel Romo ◽  
Miguel-Ángel Canela ◽  
Teresa Garnatje
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Growth Conditions ◽  
Genome Size Variation

Nuclear genome size variation in fleshy-fruited Neotropical Myrtaceae

2008 ◽  
Vol 276 (3-4) ◽  
pp. 209-217 ◽  
Author(s):  
Itayguara Ribeiro da Costa ◽  
Marcelo Carnier Dornelas ◽  
Eliana Regina Forni-Martins
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Nuclear Genome ◽  
Genome Size Variation

scholarly journals Comparative analysis reveals within-population genome size variation in a rotifer is driven by large genomic elements with highly abundant satellite DNA repeat elements

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
C. P. Stelzer ◽  
J. Blommaert ◽  
A. M. Waldvogel ◽  
M. Pichler ◽  
B. Hecox-Lea ◽  
...  
Keyword(s):  
Genome Size ◽  
Satellite Dna ◽  
Gc Content ◽  
Size Variation ◽  
Isolated Populations ◽  
Genome Size Variation ◽  
Variable Regions ◽  
Geographic Population ◽  
Genome Size Evolution ◽  
Size Evolution

Abstract Background Eukaryotic genomes are known to display an enormous variation in size, but the evolutionary causes of this phenomenon are still poorly understood. To obtain mechanistic insights into such variation, previous studies have often employed comparative genomics approaches involving closely related species or geographically isolated populations within a species. Genome comparisons among individuals of the same population remained so far understudied—despite their great potential in providing a microevolutionary perspective to genome size evolution. The rotifer Brachionus asplanchnoidis represents one of the most extreme cases of within-population genome size variation among eukaryotes, displaying almost twofold variation within a geographic population. Results Here, we used a whole-genome sequencing approach to identify the underlying DNA sequence differences by assembling a high-quality reference genome draft for one individual of the population and aligning short reads of 15 individuals from the same geographic population including the reference individual. We identified several large, contiguous copy number variable regions (CNVs), up to megabases in size, which exhibited striking coverage differences among individuals, and whose coverage overall scaled with genome size. CNVs were of remarkably low complexity, being mainly composed of tandemly repeated satellite DNA with only a few interspersed genes or other sequences, and were characterized by a significantly elevated GC-content. CNV patterns in offspring of two parents with divergent genome size and CNV patterns in several individuals from an inbred line differing in genome size demonstrated inheritance and accumulation of CNVs across generations. Conclusions By identifying the exact genomic elements that cause within-population genome size variation, our study paves the way for studying genome size evolution in contemporary populations rather than inferring patterns and processes a posteriori from species comparisons.

Sign in / Sign up

Export Citation Format

Share Document