Genome Size and the Extinction of Small Populations

LaBar, Thomas; Adami, Christoph

doi:10.1007/978-3-030-39831-6_14

Cited by 7 publications

(4 citation statements)

References 69 publications

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“…3 ). In-silico modelling provides a potential mechanism for this finding, whereby genome expansion drives extinction risk in small populations by increasing the lethal mutational burden (LaBar & Adami, 2020). Restricted ranges may also interact with major anthropogenic impacts like land conversion and species overexploitation to further exacerbate risk.…”

Section: Discussionmentioning

confidence: 99%

Genome size is positively correlated with extinction risk in herbaceous angiosperms

Gomez,

Brown,

Pironon

et al. 2023

Preprint

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SummaryAngiosperms with large genomes experience nuclear-, cellular- and organism-level constraints that may limit their phenotypic plasticity and ecological niche. These constraints have been documented to vary across lineages, life-history strategies, ecogeographic patterns and environmental conditions. Therefore, we test the hypotheses that extinction risk is higher in large-genomed compared to small-genomed species, and that the effect of genome size varies across three selected covariates: life form, endemism, and climatic zones.We collated genome size and extinction risk information for a representative sample of angiosperms comprising 3,250 species, which we analyzed alongside life form, endemism and climate variables using a phylogenetic framework.Angiosperm genome size is positively correlated with extinction risk, a pattern driven by a signal in herbaceous but not woody species, regardless of climate and endemism. The influence of genome size is stronger in endemic herbaceous species, but is relatively homogenous across different climates. Beyond its indirect link via endemism and climate, genome size also influences extinction risk directly and significantly.Genome size may serve as a proxy for difficult-to-measure parameters associated with resilience and vulnerability in herbaceous angiosperms. Therefore, it merits further exploration as a useful biological attribute for understanding intrinsic extinction risk and augmenting plant conservation efforts.

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Section: Discussionmentioning

confidence: 99%

Genome size is positively correlated with extinction risk in herbaceous angiosperms

Gomez,

Brown,

Pironon

et al. 2023

Preprint

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“…4a). Associations between genome size, seed size, and ecological niche might be reinforced by the fact that species with larger genomes have greater extinction risk (Vinogradov, 2003; LaBar & Adami, 2020; Soto Gomez et al, in prep).…”

Section: Discussionmentioning

confidence: 99%

The global distribution of angiosperm genome size is shaped by climate

Bureš

Elliott

Veselý

et al. 2022

Preprint

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(1) Evolution of genome size is shaped by various intrinsic and extrinsic factors. We explored three long-standing hypotheses concerning factors shaping the global distribution of genome size: the mutational hazard hypothesis, the polyploidy-mediated hypothesis and the climate-mediated hypothesis. (2) We compiled the largest genome size dataset to date, encompassing >5% of known angiosperm species and analyzed genome size distribution using a comprehensive geographic distribution dataset for all angiosperms across all continents. (3) Angiosperm species with large range sizes only have small genomes, consistent with the mutational hazard hypothesis. We also uncovered a unique latitudinal pattern in the distribution of genome size diversity. Climate had a strong effect on the latitudinal pattern in genome size, while the effect of polyploidy was small. Contrary to the unimodal latitudinal patterns found for plant size traits and polyploidy, the increase in angiosperm genome sizes from the equator to 40-50 degrees N/S is probably mediated by different (mostly climatic) mechanisms from those underpinning the decrease in genome sizes observed from 40-50 degrees northwards. (4) Overall, our global analyses highlight that species range size and climate factors are the main drivers shaping the global distribution of angiosperm genome sizes, with their relative importance varying across the latitudinal gradient.

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“…Our observations confirm those made by Lynch and Conery (2003) that an increased genetic drift, here associated with a decreased population size, increases the genome size. Our result also point towards an equilibrium genome size: a sufficient number of genes makes it possible to fine-tune the phenotype to the environment, but the genome also has to be short enough to prevent the degeneration caused by an excess of chromosomal rearrangements (Knibbe et al, 2007; LaBar and Adami, 2020). Increasing the mutation rate or the population size displaces this equilibrium toward shorter genomes, either through a more efficient genome purification of non-coding sequences (when increasing N ) or a loss of both coding and non-coding sequences to recover a minimal level of robustness (when increasing µ ).…”

Section: Discussionmentioning

confidence: 71%

Genome streamlining: effect of mutation rate and population size on genome size reduction

Luiselli,

Rouzaud-Cornabas,

Lartillot

et al. 2024

Preprint

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Genome streamlining, i.e. genome size reduction, is observed in bacteria with very different life traits, including endosymbiotic bacteria and several marine bacteria, raising the question of its evolutionary origin. None of the hypotheses proposed in the literature is firmly established, mainly due to the many confounding factors related to the diverse habitats of species with streamlined genomes. Computational models may help overcome these difficulties and rigorously test hypotheses. In this work, we used Aevol, a platform designed to study the evolution of genome architecture, to test two main hypotheses: that an increase in population size (N) or mutation rate (mu) could cause genome reduction. Pre-evolved individuals were transferred into new conditions, characterized by an increase in population size or mutation rate. In our experiments, both conditions lead to streamlining. However, they lead to very different genome structures. Under increased population size, genomes loose a significant fraction of non-coding sequences, but maintain their coding size, resulting in densely packed genomes (akin to streamlined marine bacteria genomes). By contrast, under increased mutation rate, genomes loose coding and non-coding sequences (akin to endosymbiotic bacteria genomes). Hence, both factors lead to an overall reduction in genome size, but the coding density of the genome appears to be determined by N x mu. Thus, a broad range of genome size and density can be achieved by different combinations of N and mu. Our results suggest that genome size and coding density are determined by the interplay between selection for phenotypic adaptation and selection for robustness.

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Genome Size and the Extinction of Small Populations

Cited by 7 publications

References 69 publications

Genome size is positively correlated with extinction risk in herbaceous angiosperms

Genome size is positively correlated with extinction risk in herbaceous angiosperms

The global distribution of angiosperm genome size is shaped by climate

Genome streamlining: effect of mutation rate and population size on genome size reduction

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