Putatively asexual chrysophytes have meiotic genes: evidence from transcriptomic data

Kraus, Diana; Chi, Jingyun; Boenigk, Jens; Beißer, Daniela; Graupner, Nadine; Dunthorn, Micah

doi:10.7717/peerj.5894

Cited by 8 publications

(6 citation statements)

References 42 publications

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“…On theoretical grounds based on the genetic advantages of recombination, it has been argued that most protists are nevertheless likely cryptically sexual at least occasionally (Dunthorn and Katz 2010;Hofstatter and Lahr 2019). And, on experimental grounds, evidence for this cryptic sex throughout the protists has been found by inventorying meiotic genes in different putative asexual lineages (Ramesh et al 2005;Malik et al 2008;Chi et al 2014b;Dunthorn et al 2017;Hofstatter et al 2018;Kraus et al 2018), although these meiotic genes could be used just for selfing or for non-canonical genetic pathways (Dunthorn et al 2017). Sex has, however, been lost in some lineages, some of which could be ancient (Doerder 2014).…”

Section: Sex and Reproduction In Protistsmentioning

confidence: 99%

Genome Evolution of Asexual Organisms and the Paradox of Sex in Eukaryotes

Hörandl

Bast

Brandt

et al. 2020

Evolutionary Biology—A Transdisciplinary Approach

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The predominance of sex in eukaryotes is still enigmatic. Sex, a composed process of meiosis and mixis cycles, confers high costs but the selective advantages remain unclear. In this review, we focus on potentially detrimental effects of asexuality on genome evolution. Theory predicts that asexual lineages should suffer from lack of meiotic DNA repair, accumulation of deleterious mutations, proliferation

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Section: Sex and Reproduction In Protistsmentioning

confidence: 99%

Genome Evolution of Asexual Organisms and the Paradox of Sex in Eukaryotes

Hörandl

Bast

Brandt

et al. 2020

Evolutionary Biology—A Transdisciplinary Approach

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“…The existence of cryptic sexual processes in putative asexuals such as Giardia and Trichomonas was proposed based on testing for the presence of the meiosis‐specific machinery . The same approach was later applied to other putative asexual groups with similar results, but many seemingly asexual lineages remain to be investigated.…”

Section: Meiosis Toolkit Can Reveal the Nature Of Asexual Scandalsmentioning

confidence: 99%

All Eukaryotes Are Sexual, unless Proven Otherwise

Hofstatter

Lahr

2019

BioEssays

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Here a wide distribution of meiotic machinery is shown, indicating the occurrence of sexual processes in all major eukaryotic groups, without exceptions, including the putative “asexuals.” Meiotic machinery has evolved from archaeal DNA repair machinery by means of ancestral gene duplications. Sex is very conserved and widespread in eukaryotes, even though its evolutionary importance is still a matter of debate. The main processes in sex are plasmogamy, followed by karyogamy and meiosis. Meiosis is fundamentally a chromosomal process, which implies recombination and ploidy reduction. Several eukaryotic lineages are proposed to be asexual because their sexual processes are never observed, but presumed asexuality correlates with lack of study. The authors stress the complete lack of meiotic proteins in nucleomorphs and their almost complete loss in the fungus Malassezia. Inversely, complete sets of meiotic proteins are present in fungal groups Glomeromycotina, Trichophyton, and Cryptococcus. Endosymbiont Perkinsela and endoparasitic Microsporidia also present meiotic proteins.

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“…Mitotic divisions lead to the liberation of zoospores and would be analogous to vegetative reproduction. Recently, Kraus et al (2019) observed evidence for meiotic or meiosis-related genes based on transcriptomic data, suggesting they are "secretly sexual. "…”

Section: Chrysophyceaementioning

confidence: 99%

Let's talk about sex: Why reproductive systems matter for understanding algae

Krueger‐Hadfield

2024

Journal of Phycology

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Sex is a crucial process that has molecular, genetic, cellular, organismal, and population‐level consequences for eukaryotic evolution. Eukaryotic life cycles are composed of alternating haploid and diploid phases but are constrained by the need to accommodate the phenotypes of these different phases. Critical gaps in our understanding of evolutionary drivers of the diversity in algae life cycles include how selection acts to stabilize and change features of the life cycle. Moreover, most eukaryotes are partially clonal, engaging in both sexual and asexual reproduction. Yet, our understanding of the variation in their reproductive systems is largely based on sexual reproduction in animals or angiosperms. The relative balance of sexual versus asexual reproduction not only controls but also is in turn controlled by standing genetic variability, thereby shaping evolutionary trajectories. Thus, we must quantitatively assess the consequences of the variation in life cycles on reproductive systems. Algae are a polyphyletic group spread across many of the major eukaryotic lineages, providing powerful models by which to resolve this knowledge gap. There is, however, an alarming lack of data about the population genetics of most algae and, therefore, the relative frequency of sexual versus asexual processes. For many algae, the occurrence of sexual reproduction is unknown, observations have been lost in overlooked papers, or data on population genetics do not yet exist. This greatly restricts our ability to forecast the consequences of climate change on algal populations inhabiting terrestrial, aquatic, and marine ecosystems. This perspective summarizes our extant knowledge and provides some future directions to pursue broadly across micro‐ and macroalgal species.

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Putatively asexual chrysophytes have meiotic genes: evidence from transcriptomic data

Cited by 8 publications

References 42 publications

Genome Evolution of Asexual Organisms and the Paradox of Sex in Eukaryotes

Genome Evolution of Asexual Organisms and the Paradox of Sex in Eukaryotes

All Eukaryotes Are Sexual, unless Proven Otherwise

Let's talk about sex: Why reproductive systems matter for understanding algae

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