Genome size is positively correlated with extinction risk in herbaceous angiosperms

Abstract

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.

Why plant diversity and distribution matter

“…(2023), whose results are consistent with the large genome constraint hypothesis (Vinogradov, 2003; Knight et al ., 2005) and with the findings of Soto Gomez et al . (2023), which support the positive relationship between plant genome size and extinction risk reported by Vinogradov (2003).…”

“…The scientific literature on global biodiversity extinction remains dominated by research on vertebrates. Several studies contribute to redressing this (Bachman et al ., 2023; Gallagher et al ., 2023; Soto Gomez et al ., 2023; Brown et al ., 2023a,b), by combining WCVP geographical data with extinction risk data from the International Union for Conservation of Nature (IUCN, 2022) Red List of Threatened Species (hereafter Red List). While WCVP is comprehensive at the species level, Red List coverage of vascular plants is incomplete; fewer than one‐in‐five plants have expert assessments despite concerted efforts to increase coverage (Bachman et al ., 2023).…”

A 160 Gbp fork fern genome shatters size record for eukaryotes

“… 4 These costs, in turn, exert cascading effects impacting the biology of organisms, their ecology and their potential to persist over evolutionary timescales. 29 The results here, coupled with knowledge of genome size diversity at the lower end of the spectrum, suggest that we now know the limits, or are most likely very close to the limits of eukaryotic genome size diversity.…”

The global distribution of angiosperm genome size is shaped by climate

“…Genetic drift could facilitate genome growth in smaller‐ranged species (as proposed in the MHH), which could further reduce the range size of large‐genomed species (LGCH) and throw them into a deadly descending spiral toward extinction. This is supported by evidence showing that large‐genomed species are at higher risk of extinction (Vinogradov, 2003; Soto Gomez et al ., 2023 in this issue).…”

“…Woody angiosperms are seldom polyploid (Müntzing, 1936; Stebbins, 1940; Otto & Whitton, 2000; Zenil‐Fergusson et al ., 2017; Rice et al ., 2019), which could explain why their genomes did not increase in temperate regions. Also, the absence of a relationship between extinction risk and genome size in woody plants (Soto Gomez et al ., 2023) could suggest that genome size dynamics operate differently in woody vs herbaceous species.…”