Chromosome rearrangements are not accompanied by expected genome size change in the tree weta Hemideina thoracica (Orthoptera, Anostostomatidae)

Genome sizes vary considerably across all eukaryotes and even among closely related species. The genesis and evolutionary dynamics of that variation have generated considerable interest, as have the patterns of variation themselves. Here we review recent developments in our understanding of genome size evolution in plants, drawing attention to the higher order processes that can influence the mechanisms generating changing genome size.

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Taxonomy Advancement and Genome Size Change: Two Perspectives on RNA Virus Genetic Diversity

Virus Evolution: Current Research and Future Directions ◽

10.21775/9781910190234.07 ◽

2016 ◽

pp. 215-232

Author(s):

Chris Lauber ◽

Alexander E. Gorbalenya

Keyword(s):

Genetic Diversity ◽

Genome Size ◽

Rna Virus ◽

Size Change

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Within-population genome size variation is mediated by multiple genomic elements that segregate independently during meiosis

Genome Biology and Evolution ◽

10.1093/gbe/evz253 ◽

2019 ◽

Author(s):

Claus-Peter Stelzer ◽

Maria Pichler ◽

Peter Stadler ◽

Anita Hatheuer ◽

Simone Riss

Keyword(s):

Genome Size ◽

Size Variation ◽

Species Variation ◽

Evolutionary Potential ◽

Short Term ◽

Genome Size Variation ◽

Size Change ◽

Diploid Genome ◽

Individual Level ◽

Size Number

Abstract Within-species variation in genome size has been documented in many animals and plants. Despite its importance for understanding eukaryotic genome diversity, there is only sparse knowledge about how individual-level processes mediate genome size variation in populations. Here we study a natural population of the rotifer Brachionus asplanchnoidis whose members differ up to 1.9-fold in diploid genome size, but were still able to interbreed and produce viable offspring. We show that genome size is highly heritable and can be artificially selected up or down, but not below a certain basal diploid genome size for this species. Analyses of segregation patterns in haploid males reveal that large genomic elements (several megabases in size) provide the substrate of genome size variation. These elements, and their segregation patterns, explain the generation of new genome size variants, the short-term evolutionary potential of genome size change in populations, and some seemingly paradoxical patterns, like an increase in genome size variation among highly inbred lines. Our study suggests that a conceptual model involving only two variables, (1) a basal genome size of the population, and (2) a vector containing information on additional elements that may increase genome size in this population (size, number, and meiotic segregation behaviour), can effectively address most scenarios of short-term evolutionary change of genome size in a population.

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Peripatric speciation associated with genome expansion and female-biased sex ratios in the moss genus Ceratodon

10.1101/227280 ◽

2017 ◽

Cited By ~ 1

Author(s):

Marta Nieto-Lugilde ◽

Olaf Werner ◽

Stuart F. McDaniel ◽

Petr Koutecký ◽

Jan Kučera ◽

...

Keyword(s):

New Species ◽

Genome Size ◽

Population Divergence ◽

Size Change ◽

Pcr Marker ◽

Mediterranean Populations ◽

Homogeneous Groups ◽

A Genome ◽

Peripatric Speciation ◽

Well Differentiated

ABSTRACTPREMISE OF THE STUDYA period of allopatry is widely believed to be essential for the evolution of reproductive isolation. However, strict allopatry may be difficult to achieve in some cosmopolitan, spore-dispersed groups, like mosses. Here we examine the genetic and genome size diversity in Mediterranean populations of the moss Ceratodon purpureus s.l. to evaluate the role of allopatry and ploidy change in population divergence.METHODSWe sampled populations of the genus Ceratodon from mountainous areas and lowlands of the Mediterranean region, and from western and central Europe. We performed phylogenetic and coalescent analyses on sequences from five nuclear introns and a chloroplast locus to reconstruct their evolutionary history. We also estimated the genome size using flow cytometry, employing propidium iodide, and determined their sex using a sex-linked PCR marker.KEY RESULTSTwo well differentiated clades were resolved, discriminating two homogeneous groups: the widespread C. purpureus and a local group mostly restricted to the mountains in southern Spain. The latter also possessed a genome size 25% larger than the widespread C. purpureus, and the samples of this group consist entirely of females. We also found hybrids, and some of them had a genome size equivalent to the sum of the C. purpureus and Spanish genome, suggesting that they arose by allopolyploidy.CONCLUSIONSThese data suggest that a new species of Ceratodon arose via peripatric speciation, potentially involving a genome size change and a strong female-biased sex ratio. The new species has hybridized in the past with C. purpureus.

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Genome Size Evolution Differs Between Drosophila Subgenera with Striking Differences in Male and Female Genome Size in Sophophora

G3 Genes|Genome|Genetics ◽

10.1534/g3.119.400560 ◽

2019 ◽

Vol 9 (10) ◽

pp. 3167-3179 ◽

Cited By ~ 1

Author(s):

Carl E. Hjelmen ◽

Heath Blackmon ◽

V. Renee Holmes ◽

Crystal G. Burrus ◽

J. Spencer Johnston

Keyword(s):

Chromosome Number ◽

Genome Size ◽

Related Species ◽

Sexual Differences ◽

Clear Correlation ◽

Size Change ◽

Closely Related Species ◽

Rates Of Change ◽

Genome Size Evolution ◽

Structural Differences

Genome size varies across the tree of life, with no clear correlation to organismal complexity or coding sequence, but with differences in non-coding regions. Phylogenetic methods have recently been incorporated to further disentangle this enigma, yet most of these studies have focused on widely diverged species. Few have compared patterns of genome size change in closely related species with known structural differences in the genome. As a consequence, the relationship between genome size and differences in chromosome number or inter-sexual differences attributed to XY systems are largely unstudied. We hypothesize that structural differences associated with chromosome number and X-Y chromosome differentiation, should result in differing rates and patterns of genome size change. In this study, we utilize the subgenera within the Drosophila to ask if patterns and rates of genome size change differ between closely related species with differences in chromosome numbers and states of the XY system. Genome sizes for males and females of 152 species are used to answer these questions (with 92 newly added or updated estimates). While we find no relationship between chromosome number and genome size or chromosome number and inter-sexual differences in genome size, we find evidence for differing patterns of genome size change between the subgenera, and increasing rates of change throughout time. Estimated shifts in rates of change in sex differences in genome size occur more often in Sophophora and correspond to known neo-sex events.

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Diploidization and genome size change in allopolyploids is associated with differential dynamics of low- and high-copy sequences

The Plant Journal ◽

10.1111/tpj.12168 ◽

2013 ◽

Vol 74 (5) ◽

pp. 829-839 ◽

Cited By ~ 71

Author(s):

Simon Renny-Byfield ◽

Ales Kovarik ◽

Laura J. Kelly ◽

Jiri Macas ◽

Petr Novak ◽

...

Keyword(s):

Genome Size ◽

Size Change

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The dynamics of genome size and GC contents evolution in genus Nicotiana

Brazilian Journal of Biology ◽

10.1590/1519-6984.245372 ◽

2023 ◽

Vol 83 ◽

Author(s):

Z. Hussain ◽

Y. Sun ◽

S. H. Shah ◽

H. Khan ◽

S. Ali ◽

...

Keyword(s):

Genome Size ◽

Gc Content ◽

Species Loss ◽

Evolutionary Time ◽

Size Change ◽

Ancestral Species ◽

Genomic Changes ◽

Nicotiana Species ◽

Content Variation ◽

Gc Contents

Abstract Hybridization and Polyploidization are most common of the phenomenon observed in plants, especially in the genus Nicotiana leading to the duplication of genome. Although genomic changes associated with these events has been studied at various levels but the genome size and GC content variation is less understood because of absence of sufficient genomic data. In this study the flow cytometry technique was used to uncover the genome size and GC contents of 46 Nicotiana species and we compared the genomic changes associated with the hybridization events along evolutionary time scale. The genome size among Nicotiana species varied between 3.28 pg and 11.88 pg whereas GC contents varied between 37.22% and 51.25%. The tetraploid species in genus Nicotiana including section Polydiclae, Repandae, Nicotiana, Rustica and Sauveolentes revealed both up and downsizing in their genome sizes when compared to the sum of genomes of their ancestral species. The genome sizes of three homoploid hybrids were found near their ancestral species. Loss of large genome sequence was observed in the evolutionary more aged species (>10 Myr) as compared to the recently evolved one’s (<0.2 Myr). The GC contents were found homogenous with a mean difference of 2.46% among the Nicotiana species. It is concluded that genome size change appeared in either direction whereas the GC contents were found more homogenous in genus Nicotiana.

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Within-population genome size variation is mediated by multiple genomic elements that segregate independently during meiosis

10.1101/623470 ◽

2019 ◽

Author(s):

Claus-Peter Stelzer ◽

Maria Pichler ◽

Peter Stadler ◽

Anita Hatheuer ◽

Simone Riss

Keyword(s):

Genome Size ◽

Size Variation ◽

Species Variation ◽

Genome Diversity ◽

Evolutionary Potential ◽

Short Term ◽

Genome Size Variation ◽

Size Change ◽

Individual Level ◽

Size Number

AbstractWithin-species variation in genome size has been documented in many animals and plants. Despite its importance for understanding eukaryotic genome diversity, there is only sparse knowledge about how individual-level processes mediate genome size variation in populations. Here we study a natural population of the rotifer Brachionus asplanchnoidis whose members differ up to 1.9-fold in genome size, but were still able to interbreed and produce viable offspring. We show that genome size is highly heritable and can be artificially selected up or down, but not beyond a minimum diploid genome size. Analyses of segregation patterns in haploid males reveal that large genomic elements (several megabases in size) provide the substrate of genome size variation. These elements, and their segregation patterns, explain the generation of new genome size variants, the short-term evolutionary potential of genome size change in populations, and some seemingly paradoxical patterns, like an increase in genome size variation among highly inbred lines. Our study suggests that a conceptual model involving only two variables, (1) a minimum genome size of the population, and (2) a vector containing information on additional elements that may increase genome size in this population (size, number, and meiotic segregation behaviour), can effectively address most scenarios of short-term evolutionary change of genome size in a population.

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