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Cited by 313Protist diversity and phylogenyPaleontology and Stratigraphy of FossilsPhotosynthetic Processes and Mechanisms

Cyanobacteria and the Great Oxidation Event: evidence from genes and fossils

Open access
Schirrmeister, Bettina E., Gugger, Muriel, Donoghue, Philip C. J.·2015·Palaeontology
DOI 10.1111/pala.12178PMC PMC4755140
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Abstract

Cyanobacteria are among the most ancient of evolutionary lineages, oxygenic photosynthesizers that may have originated before 3.0 Ga, as evidenced by free oxygen levels. Throughout the P recambrian, cyanobacteria were one of the most important drivers of biological innovations, strongly impacting early Earth's environments. At the end of the A rchean E on, they were responsible for the rapid oxygenation of Earth's atmosphere during an episode referred to as the G reat O xidation E vent (GOE). However, little is known about the origin and diversity of early cyanobacterial taxa, due to: (1) the scarceness of P recambrian fossil deposits; (2) limited characteristics for the identification of taxa; and (3) the poor preservation of ancient microfossils. Previous studies based on 16 S r RNA have suggested that the origin of multicellularity within cyanobacteria might have been associated with the GOE. However, single‐gene analyses have limitations, particularly for deep branches. We reconstructed the evolutionary history of cyanobacteria using genome scale data and re‐evaluated the P recambrian fossil record to get more precise calibrations for a relaxed clock analysis. For the phylogenomic reconstructions, we identified 756 conserved gene sequences in 65 cyanobacterial taxa, of which eight genomes have been sequenced in this study. Character state reconstructions based on maximum likelihood and Bayesian phylogenetic inference confirm previous findings, of an ancient multicellular cyanobacterial lineage ancestral to the majority of modern cyanobacteria. Relaxed clock analyses provide firm support for an origin of cyanobacteria in the A rchean and a transition to multicellularity before the GOE. It is likely that multicellularity had a greater impact on cyanobacterial fitness and thus abundance, than previously assumed. Multicellularity, as a major evolutionary innovation, forming a novel unit for selection to act upon, may have served to overcome evolutionary constraints and enabled diversification of the variety of morphotypes seen in cyanobacteria today.

AI snapshot

Written from the paper’s full text.

TL;DR

Genome-scale phylogenomics and relaxed molecular clock analyses of 65 cyanobacterial taxa support an Archean origin of cyanobacteria and an origin of multicellularity before the Great Oxidation Event, with multicellularity later lost and occasionally regained. The authors argue this early multicellularity may have increased cyanobacterial abundance and oxygen production, contributing to the GOE.

Key findings

  • The phylogenomic tree, based on 756 conserved proteins (197,761 amino acid sites) from 65 cyanobacterial taxa, recovered six major clades with full bootstrap support; 100% maximum likelihood bootstrap support was inferred for 57 of 64 branches, compared with 24 of 64 branches in the 16S/23S rRNA tree.
  • Ancestral character state reconstruction inferred a very early transition to multicellularity at node/branch 69; multicellularity was subsequently lost at least five times and regained on one, possibly two, branches leading to *Leptolyngbya* sp. PCC 7376 and *Spirulina subsalsa* PCC 9445, so the majority of modern cyanobacteria are descendants of an ancient multicellular lineage.
  • Relaxed clock analyses, irrespective of prior assumptions for node 69, estimated that multicellularity originated before the GOE; cyanobacteria originated in the Archean/mid-Archean long before the GOE, and the majority of modern clades 2–6 evolved after the GOE.
  • Comparisons of modern cyanobacterial cell sizes to Precambrian microfossils support the inferred presence of multicellular cyanobacteria before the GOE, but the fossil record does not provide evidence for multicellular taxa among the earliest unequivocal fossil assemblages at 3.33–3.45 Ga.

Methods

  • Taxon sampling and phylogenomics: 65 cyanobacterial taxa were analyzed, including 27 unicellular (sections I–II) and 38 multicellular (sections III–V) taxa; eight additional cyanobacterial genomes were sequenced. A total of 756 highly conserved proteins were identified, aligned, and concatenated into a 197,761-amino-acid supermatrix; maximum likelihood trees were reconstructed with RAxML using the LG + Γ model and 1000 bootstrap resamplings, alongside a concatenated 16S/23S rRNA tree.
  • Ancestral character state reconstruction: maximum likelihood methods in the R ape package and Bayesian inference in BayesTraits were used; MCMC analyses ran for 1,010,000 iterations with a 10,000 burn-in, estimating transition rates q01 (to multicellularity) and q10 (to unicellularity).
  • Divergence time estimation: relaxed clocks with lognormal rate distribution were applied in MCMCTREE/PAML, using three calibrations—origin of Cyanobacteria, origin of sections IV and V capable of cellular differentiation, and origin of multicellularity at node 69. Two hypotheses were tested: multicellularity after the GOE (H1) versus before the GOE (H2); four MCMC analyses ran for 10 million generations, sampling every 100 generations with 50% burn-in.

Limitations

  • Stated: deep divergences are limited by the lack of evolutionary information retained in molecular data over long timescales, weaknesses in phylogenetic models, paucity of calibration points, potential misassignment of calibrations, and the likelihood that fossil ages poorly approximate clade ages; posterior node age estimates had large 95% confidence intervals that prevented precise dating.
  • Stated: the Precambrian fossil record is patchy at best; the earliest unequivocal fossil assemblages at 3.33–3.45 Ga do not provide evidence for multicellular cyanobacteria, and filament diameters in older fossils are described as “more probabilistic than deterministic” evidence for cyanobacteria.
  • Evident from the text: the analyses depend on debated fossil interpretations and geochemical inferences for calibration, use only uniform prior distributions, and showed that user-specified priors can differ from effective priors, although the authors judged the age ranges similar enough to accept.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1111/pala.12178

Cites

98 of 98 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 90 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Relaxed clock analyses provide firm support for an origin of cyanobacteria in the Archean.

    “Relaxed clock analyses provide firm support for an origin of cyanobacteria in the Archean and a transition to multicellularity before the GOE.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The divergence of the Gloeobacter lineage from the stem lineage leading to all other extant cyanobacteria occurred between 3.85 and 2.918 Ga (analyses A, C) or between 3.85 and 2.45 Ga (analyses B, D).
  • Findingown data

    Relaxed clock analyses provide firm support for a transition to multicellularity before the GOE.

    “Relaxed clock analyses provide firm support for an origin of cyanobacteria in the Archean and a transition to multicellularity before the GOE.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The most recent common ancestor of subsections IV and V cyanobacteria originated after the GOE but before 1.957 Ga.
  • Findingown data

    Results of all analyses suggest a very early transition to multicellularity at node/branch 69.

    “Results of all analyses suggest a very early transition to multicellularity at ‘node/branch 69’ (Fig. 3; Fig. S3; Table S3).”
    Quote in the paperSubstantial claim
  • Findingown data

    Changing the widths of the uniform distribution in several runs supported an early transition to multicellularity even further.

    “Changing the widths of the uniform distribution in several runs supported an early transition to multicellularity even further (Fig. S3, online Supporting Information).”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    Synechococcus isolated from hot springs are the first group to split from the rest of Cyanobacteria.

    “Assuming that Gloeobacter groups closest to a eubacterial outgroup, as previously suggested based on ribosomal (Schirrmeister et al. 2011b), and phylogenomic data (Blank and Sanchez‐Baracaldo 2010; Shih et al. 2013), Synechococcus isolated from hot springs are the first group to split from the rest of Cyanobacteria, followed by an early branching ‘Clade 1’ of unicellular and multicellular cyan”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 20
  • May combine two claims. 34

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    An evolutionary model assuming equal transition rates resulted in a rate of 0.7575 (standard deviation = 0.1978).

    “An evolutionary model assuming equal transition rates resulted in rates of 0.7575 (standard deviation = 0.1978).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Clade 6 comprises the majority of the subsections I to III cyanobacteria and is well supported in the phylogenomic tree, but not resolved in the ribosomal tree.

    “‘Clade 6’ comprises the majority of the subsections I to III cyanobacteria (except marine picocyanobacteria, hot spring Synechococcus and early‐branching multicellular taxa) and is well supported in the phylogenomic tree, but not resolved in the ribosomal tree (BS: 41%).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For the cyanobacterial stem lineage, posterior age estimates were almost uniformly distributed in Hypothesis 1 and shifted towards an origin of cyanobacteria prior 3.5 Ga for Hypothesis 2.

    “For the cyanobacterial stem lineage (calibration 1; Fig. 4), posterior age estimates were almost uniformly distributed in Hypothesis 1 and shifted towards an origin of cyanobacteria prior 3.5 Ga for Hypothesis 2.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Across the phylogeny, multicellularity is subsequently lost at least five times and regained on one, possibly two, branch leading to Leptolyngbya sp. PCC 7376 and Spirulina subsalsa PCC 9445.

    “Across the phylogeny, multicellularity is subsequently lost at least five times and regained on one, possibly two, branch leading to Leptolyngbya sp. PCC 7376 and Spirulina subsalsa PCC 9445.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    100% maximum likelihood bootstrap values supported 24 of 64 branches of the ribosomal tree, whereas 100% bootstrap support was inferred for 57 of 64 branches of the genomic tree.

    “While 100% maximum likelihood bootstrap (BS) values supported just 24 of 64 branches of the ribosomal tree, 100% bootstrap support was inferred for 57 of 64 branches of the genomic tree.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The use of a large data set (197,766 amino acid sites) helped overcome limitations of previous analyses, substantially improving statistical support across cyanobacterial phylogeny compared with single-gene analyses, and corroborating hypotheses of an early origin of multicellularity in Cyanobacteria.

    “In this study, the use of an impressively large data set (197 766 amino acid sites) helped to overcome the limitations previous analyses might have had, not only substantially improving the statistical support across cyanobacterial phylogeny in comparison with single‐gene analyses, but also corroborating the hypotheses of an early origin of multicellularity in Cyanobacteria (Schirrmeister et al. 2”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Schirrmeister et al. 2011b, 2013

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  • May combine two claims.

    Findingown data

    Our results show that multicellularity evolved very early among cyanobacteria and divergence time estimations confirm previous suggestions of an origin of multicellularity prior to the GOE, independently of whether the 2.0 Ga fossil akinete calibration is used.

    “Our results show that multicellularity evolved very early among cyanobacteria and divergence time estimations (Fig. 5) confirm previous suggestions of an origin of multicellularity prior to the GOE, independently of whether the 2.0 Ga fossil akinete calibration is used.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Cyanobacteria exhibit impressive morphological diversity and have been classified into five subsections.

    “In addition to their ecological variety, cyanobacteria exhibit impressive morphological diversity, particularly for prokaryotes. On this basis, cyanobacteria have been classified and divided into five subsections (Rippka et al. 1979; Castenholz 2001).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Rippka et al. 1979

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    • cites Castenholz 2001

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    Interpretationcitation

    The transition to multicellularity with its increase in overall size could have had a similar effect on metabolic rates in cyanobacteria.

    “The transition to multicellularity with its increase in overall size could have had a similar effect in cyanobacteria.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    Current competing hypotheses that attempt to explain the origin of cyanobacteria ignore the possibility of evolutionary innovations that could have influenced fitness and abundance of cyanobacteria.

    “These hypotheses, however, ignore the possibility of evolutionary innovations that could have influenced fitness and, hence, abundance of cyanobacteria.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Multicellularity may have served to overcome evolutionary constraints and enabled diversification of the variety of morphotypes seen in cyanobacteria today.

    “Multicellularity, as a major evolutionary innovation, forming a novel unit for selection to act upon, may have served to overcome evolutionary constraints and enabled diversification of the variety of morphotypes seen in cyanobacteria today.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    Difficulties in obtaining accurate age estimates for deep speciation events include lack of evolutionary information in molecular data, weaknesses in the phylogenetic model, and paucity of calibration points.

    “Difficulties in obtaining accurate age estimates for such deep speciation events may include: (1) the lack of evolutionary information retained in molecular data over such long timescales; (2) weaknesses in the phylogenetic model to correctly infer evolutionary processes that took place over such long time periods; and (3) the paucity of calibration points for divergence time estimation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Further difficulties of calibrations involve potential misassignment to clades and the likelihood that the age of calibrating fossils is a poor approximation of their clade age.

    “Further difficulties of calibrations involve: (1) the potential for their misassignment to clades; and (2) the likelihood that the age of the calibrating fossils is a poor approximation of their clade age.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Although the limiting factor on precision in divergence time studies is uncertainty associated with fossil calibrations, much of the uncertainty associated with phylogeny and divergence time estimation can be diminished by employing genome scale data.

    “Although the limiting factor on precision in divergence time studies is invariably the uncertainty associated with the fossil calibrations (dos Reis and Yang 2013), in terms of the degree to which fossil minima approximate the true time of divergence, much of the uncertainty associated with phylogeny and divergence time estimation can be diminished by employing genome scale data (dos Reis et al. 2”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites dos Reis and Yang 2013

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    • cites dos Reis et al. 2012

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    Premisecitation

    The overall fossil record is patchy and provides only glimpses into the history of early prokaryotes.

    “Although many multicellular fossil remains from the Archean and Proterozoic (Altermann and Schopf 1995; Schopf 2006) have been interpreted as cyanobacteria, the overall fossil record is patchy at best and provides only glimpses into the history of these early prokaryotes.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Altermann and Schopf 1995

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    • cites Schopf 2006

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    Premisecitation

    The appearance of cyanobacterial fossils attributed to subsections IV and V occurs after the GOE, supporting the hypothesis that heterocyst formation evolved after the increase in atmospheric oxygen.

    “The appearance of cyanobacterial fossils attributed to subsections IV and V cyanobacteria occurs after the GOE, supporting the hypothesis that heterocyst formation evolved after the increase in atmospheric oxygen to allow for nitrogen fixation, spatially separated from photosynthesis (Tomitani et al. 2006).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Tomitani et al. 2006

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Subsections IV and V cyanobacteria can form differentiated cells such as heterocysts for nitrogen fixation and akinetes.

    “bacteria in subsections IV and V have the ability to form differentiated cells, such as metabolically specialized heterocysts for nitrogen fixation and resting cells, so called akinetes (Flores and Herrero 2010).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Flores and Herrero 2010

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Subsection V cyanobacteria are the only cyanobacteria that grow multiseriate filaments and exhibit true branching.

    “Taxa belonging to subsection V are the only cyanobacteria that grow multiseriate filaments (varying cell width) and in several planes exhibit ‘true’ branching, not to be confused with ‘false’ branching (Rippka et al. 1979; Gugger and Hoffmann 2004).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Rippka et al. 1979

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    • cites Gugger and Hoffmann 2004

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  • May combine two claims.

    Premisecitation

    Cyanobacteria are among the most ancient evolutionary lineages and may have originated before 3.0 Ga.

    “Cyanobacteria are among the most ancient of evolutionary lineages, oxygenic photosynthesizers that may have originated before 3.0 Ga, as evidenced by free oxygen levels.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Crowe et al. 2013

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    • cites Lyons et al. 2014

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  • May combine two claims.

    Study design and conductown data

    Age ranges of specified and effective priors were similar and could be accepted for the divergence time analyses.

    “Age ranges of specified and effective priors were similar, however, and could be accepted for the divergence time analyses.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    For all analyses, accepted changes to the chains had values of approximately 30% at the time of convergence.

    “For all analyses, accepted changes to the chains had values of approximately 30% at the time of convergence.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Based on Sm-Nd isotopes, two kerogen-rich shale samples of the Franceville Group were dated 2.099 Ga ± 115 Myr to 2.036 Ga ± 79 Myr, suggesting a conservative minimum constraint for tree calibration of 1.957 Ga.

    “Based on Sm‐Nd isotopes, two kerogen‐rich shale samples of the Franceville Group were dated 2.099 Ga ± 115 Myr to 2.036 Ga ± 79 Myr, which suggests a conservative minimum constrain for the tree calibration of 1.957 Ga (Bros et al. 1992).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bros et al. 1992

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  • Classified as probably not a substantial claim.

    Premisecitation

    For analyses B and D, the lower limit on the age of crown Cyanobacteria is based on the estimated beginning of the GOE.

    “For analyses B and D, the lower limit on the age of crown Cyanobacteria is based on the estimated beginning of the GOE (Bekker et al. 2004).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bekker et al. 2004

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    Study design and conductnone given

    All MCMC runs exhibited evidence of sufficient mixing.

    “All MCMC runs exhibited evidence of sufficient mixing.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Fossil akinetes classified as Archaeoellipsoides have been reported from various intervals through the Proterozoic, but the microfossils of the Franceville Group are the earliest of these occurrences.

    “These fossil akinetes, classified as Archaeoellipsoides, have been reported from various intervals through the Proterozoic (Horodyski and Donaldson 1980; Golubic et al. 1995; Srivastava 2005); however, the microfossils of the Franceville Group are the earliest of these occurrences.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Horodyski and Donaldson 1980

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    • cites Golubic et al. 1995

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    • cites Srivastava 2005

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    Premisecitation

    Mo isotope evidence from the Sinqeni Fm., Pongola Supergroup, South Africa, indicates indirectly the presence of manganese oxidation, a process that would require abundant free oxygen.

    “The lower limit on the age of crown Cyanobacteria in analyses A and C is based on Mo isotope evidence for oxygen production from the Sinqeni Fm., Pongola Supergroup, South Africa, indicating indirectly the presence of manganese oxidation, a process that would require abundant free oxygen (Planavsky et al. 2014).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Planavsky et al. 2014

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  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    A previous study by Schirrmeister et al. (2013) estimated divergence times pointing towards an origin of cyanobacteria in the Archean Eon, with multicellularity more likely originating before the GOE.

    “Applying 16S rRNA sequence data and a set of different calibration assumptions, a previous study by Schirrmeister et al. (2013) estimated divergence times that pointed towards an origin of cyanobacteria in the Archean Eon, with multicellularity more likely originating before the GOE.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Schirrmeister et al. (2013)

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  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing). May combine two claims.

    Premisecitation

    Previous hypotheses have argued for an origin of Cyanobacteria shortly before the GOE, followed by a rapid accumulation of oxygen as observed during the GOE.

    “Previous hypotheses have argued for an origin of Cyanobacteria shortly before the GOE (Kirschvink and Kopp 2008), followed by a rapid accumulation of oxygen as observed during the GOE.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Kirschvink and Kopp 2008

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    Premisecitation

    More than 2.83-Gyr-old reef systems from Mushandike, Zimbabwe, and Steep Rock, Canada, seem to have been formed in oxic waters and support hypotheses of Archean oxygen oases based on the absence of mass-independent sulphur fractionation.

    “More than 2.83‐Gyr‐old reef systems from Mushandike, Zimbabwe, and Steep Rock, Canada, seem to have been formed in oxic waters and support the hypotheses of Archean oxygen oases that were based on the absence of mass‐independent sulphur fractionation (Ohmoto et al. 2006).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ohmoto et al. 2006

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  • May combine two claims.

    Premisenone given

    16S rRNA comprises merely 1400 nucleotide sites with only half of them susceptible to change in phylum Cyanobacteria.

    “it comprises merely 1400 nucleotide sites with only half of them susceptible to change in phylum Cyanobacteria.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Calibrations of tip clades have been claimed to be unsuitable for accurate estimation of deep divergence events.

    “Additionally, calibrations of tip clades have been claimed to be unsuitable for the accurate estimation of deep divergence events (Duchene et al. 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Duchene et al. 2014

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    Premisecitation

    Several studies have found evidence of free oxygen and inferred the presence of cyanobacteria hundreds of millions of years prior to the GOE, possibly as early as 3.0 Ga.

    “Alternatively, several studies have found evidence of free oxygen and, thus, inferred the presence of cyanobacteria, hundreds of millions of years prior to the GOE, possibly as early as 3.0 Ga (Nisbet et al. 2007; Nisbet and Nisbet 2008; Crowe et al. 2013; Lyons et al. 2014).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nisbet et al. 2007

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    • cites Nisbet and Nisbet 2008

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    • cites Crowe et al. 2013

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    Premisecitation

    Shih and Matzke (2013) recovered a much more recent origin of living cyanobacterial taxa, concluding that an ancient cyanobacterial stem lineage must be responsible for late Archean oxygen levels.

    “Another study by Shih and Matzke (2013) recovered a much more recent origin of living cyanobacterial taxa concluding that an ancient cyanobacterial stem lineage must be responsible for late Archean oxygen levels.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Shih and Matzke (2013)

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    Premisecitation

    Isotopes from organic carbon in these rocks point towards cyanobacterial RuBisCO I activity in those deposits and support an origin of cyanobacteria in the Archean.

    “Isotopes from organic carbon in these rocks, additionally, point towards cyanobacterial RuBisCO I activity in those deposits and support an origin of cyanobacteria in the Archean (Nisbet et al. 2007; Nisbet and Fowler 2011).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Nisbet et al. 2007

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    • cites Nisbet and Fowler 2011

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    Premisecitation

    The ATPase subunits resulted from an ancient duplication event before the last common ancestor of all living taxa.

    “The ATPase subunits resulted from an ancient duplication event, which occurred before the last common ancestor of all living taxa and has therefore been used in the past to reconstruct the Tree of Life (Iwabe et al. 1989).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Iwabe et al. 1989

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  • May combine two claims.

    Interpretationreasoning

    The assumptions that simple filamentous cyanobacterial taxa were present in 2.0-Gyr-old deposits and that cyanobacteria were responsible for the accumulation of oxygen during the Archean indicate an existence of multicellular cyanobacteria before the GOE.

    “The assumptions that: (1) simple filamentous cyanobacterial taxa were present in 2.0‐Gyr‐old deposits; and (2) cyanobacteria were responsible for the accumulation of oxygen during the Archean, indicates an existence of multicellular cyanobacteria before the GOE.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Simple filamentous cyanobacterial taxa were present in 2.0-Gyr-old deposits.
    • The authors state this as an assumption: Cyanobacteria were responsible for the accumulation of oxygen during the Archean.

  • May combine two claims.

    Premisenone given

    Microfossils from Proterozoic and Archean deposits comprise multicellular forms, such as septate and non-septate filaments, and unicellular remains, such as spheres and rods.

    “Microfossils from Proterozoic and Archean deposits comprise multicellular forms, such as septate and non‐septate filaments, and unicellular remains, such as spheres and rods.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The origin of multicellularity was a major transition in the history of cyanobacteria, forming new units subject to selection, and offering the potential to increase cyanobacterial abundance, consequently initiating the GOE.

    “We suggest that the origin of multicellularity was a major transition in the history of cyanobacteria, forming new units to be subject to selection, and offering the potential to increase cyanobacterial abundance, consequently initiating the GOE.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Experiments have demonstrated the movement of filamentous cyanobacteria to avoid UV light, where prevention of movement resulted in UV-induced inhibition of photosynthesis.

    “Furthermore, experiments have demonstrated the movement of filamentous cyanobacteria to avoid UV light, where prevention of movement resulted in UV‐induced inhibition of photosynthesis (Kruschel and Castenholz 1998).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kruschel and Castenholz 1998

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  • May combine two claims.

    Interpretationcitation

    In Archean environments, Fe(II) toxicity could have prohibited oxygenic photosynthesis and subsequently allowed for only little oxygen production.

    “In Archean environments, Fe (II) toxicity could have prohibited oxygenic photosynthesis and subsequently allowed for only little oxygen production.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The delay in accumulation of free oxygen until the GOE has been explained by a strongly reducing atmosphere where initially produced oxygen was captured by oxygen sinks, such as reduced volcanic gases.

    “The delay in the accumulation of free oxygen until the GOE has been explained by a strongly reducing atmosphere where initially produced oxygen was captured by oxygen sinks, such as reduced volcanic gases (Catling and Claire 2005).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Catling and Claire 2005

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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Multicellularity could have provided novel possibilities for cyanobacterial diversification and adaptation to new oxygenated habitats.

    “Furthermore, multicellularity could have provided novel possibilities for cyanobacterial diversification and adaptation to new oxygenated habitats.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    As the only biological source of oxygen during the early Precambrian, cyanobacterial fitness and ecological success should have had a profound impact on the amount of free net oxygen in Earth's ocean and atmosphere.

    “As the only biological source of oxygen during the early Precambrian, cyanobacterial fitness and ecological success should have had a profound impact on the amount of free net oxygen in Earth's ocean and atmosphere.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Comparisons of modern cyanobacterial taxa to Precambrian microfossils support the inferred presence of multicellular cyanobacteria before the GOE, but the fossil record does not provide evidence for multicellular taxa among the earliest unequivocal fossil assemblages at 3.33-3.45 Ga.

    “Comparisons of modern cyanobacterial taxa to Precambrian microfossils support the inferred presence of multicellular cyanobacteria before the GOE, but the fossil record does not provide evidence for multicellular taxa among the earliest unequivocal fossil assemblages at 3.33–3.45 Ga.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Multicellularity provides selective advantage during early Earth history including movement within microbial mats to avoid lethal UV-C dosages and improved attachment to surfaces during initial mat formation that may have substantially increased the success of cyanobacterial-dominated mat communities and enabled adaptation to novel habitats.

    “Multicellularity provides selective advantage during early Earth history including: (1) movement within microbial mats to avoid lethal UV‐C dosages; and (2) improved attachment to surfaces during initial mat formation that may have substantially increased the success of cyanobacterial‐dominated mat communities and enabled adaptation to novel habitats.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationreasoning

    Increased sizes of multicellular cyanobacteria may have resulted in higher metabolic rates, hence higher photosynthetic activity and increased net oxygen production.

    “Similarly, increased sizes of multicellular cyanobacteria may have resulted in higher metabolic rates, hence, higher photosynthetic activity and increased net oxygen production.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Multicellular growth may have provided competitive advantages that resulted in higher growth success.

    “Additionally, multicellular growth may have provided competitive advantages that resulted in a higher growth success (Fig. 6).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Cyanobacteria originated in the mid-Archean, long before the GOE, with multicellular taxa evolving towards the end of the Archean.

    “Cyanobacteria originated in the mid‐Archean, long before the GOE, with multicellular taxa evolving towards the end of the Archean.”
    Quote in the paperSubstantial claim
48 of 48

  • The authors state this as an assumption.

    The divergence of the Gloeobacter lineage from the stem lineage leading to all other extant cyanobacteria occurred between 3.85 and 2.918 Ga (analyses A, C) or between 3.85 and 2.45 Ga (analyses B, D).

    “The divergence of Gloeobacter lineage from the stem lineage leading to the all other extant cyanobacterial species was assumed to have occurred some time between 3.85 and 2.918 Ga (Table 1, analyses A, C) or 3.85 and 2.45 Ga (Table 1, analyses B, D), with each time point being equally likely (uniform prior distribution).”

  • The authors state this as an assumption.

    The most recent common ancestor of subsections IV and V cyanobacteria originated after the GOE but before 1.957 Ga.

    “we assumed that the most recent common ancestor of subsections IV and V cyanobacteria must have originated after the GOE, but prior to 1.957 Ga.”

  • The authors state this as an assumption.

    The end of the Late Heavy Bombardment at 3.85 Ga can be taken as a similar age for Earth.

    “Given that the heavy lunar bombardment is estimated to have ended at 3.85 Ga, a similar age may be assumed for Earth given the proximity of the moon.”

  • The authors state this as an assumption.

    Simple filamentous cyanobacterial taxa were present in 2.0-Gyr-old deposits.

    “The assumptions that: (1) simple filamentous cyanobacterial taxa were present in 2.0‐Gyr‐old deposits; and (2) cyanobacteria were responsible for the accumulation of oxygen during the Archean, indicates an existence of multicellular cyanobacteria before the GOE.”

  • The authors state this as an assumption.

    Cyanobacteria were responsible for the accumulation of oxygen during the Archean.

    “The assumptions that: (1) simple filamentous cyanobacterial taxa were present in 2.0‐Gyr‐old deposits; and (2) cyanobacteria were responsible for the accumulation of oxygen during the Archean, indicates an existence of multicellular cyanobacteria before the GOE.”
5 of 5

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Cyanobacteria probably evolved during the Archean.

    “For example, cyanobacteria probably evolved [e.g., (3)] during this period”

    From The Archean atmosphere (2020) · cites this paper as [3]

  • Most studies suggest an earlier Paleoarchean or Mesoarchean age for oxygenic photosynthesis.

    “While some argue that oxygenic photosynthesis evolved only 50 to 100 Ma before the GOE (115), most studies suggest an earlier Paleoarchean or Mesoarchean age [e.g., (3, 118, 119)].”

    From The Archean atmosphere (2020) · cites this paper as [3]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Differentiated-clade calibration has two upper bounds

    Major

    The methods specify an upper bound of 2.45 Ga for the subsections IV and V calibration, but Table 1 gives 2.32 Ga for that calibration in every analysis.

  • Root-calibration assignments are reversed

    Major

    The text assigns the 2.918 Ga lower bound to analyses A and C and the 2.45 Ga bound to B and D. Table 1 assigns them the other way around.

  • Supermatrix length changes in the discussion

    Minor

    The discussion reports 197,766 amino acid sites, while the methods report 197,761 for the same supermatrix.

  • Five stated multicellular strains are six listed strains

    Minor

    The sampling description says five multicellular strains were sequenced, but its list names six: one each under items 1, 2, 3 and 5, and two Pseudanabaena strains under item 4.

  • Figure captions give a different narrow root bound

    Minor

    The figure caption gives 2.958 Ga as the lower bound of the narrow root calibration, whereas Table 1 gives 2.918 Ga.

  • q01 is assigned to both opposing transitions

    Minor

    The results define q01 as both the gain and loss of multicellularity. The methods instead define q01 as the gain and q10 as the transition back to unicellularity.

  • Western Australian deposit is dated in Ma instead of Ga

    Minor

    The discussion dates the deposit containing Oscillatoriopsis to approximately 2.0 Ma. The methods describe the Western Australian deposit containing that fossil as approximately 2.0 Ga.

  • Figure 2 reverses the hypothesis labels

    Minor

    Figure 2 calls an origin before the GOE Hypothesis 1 and an origin after it Hypothesis 2. The results define Hypothesis 1 as after the GOE and Hypothesis 2 as before it.

8 of 8

Cites

1 retracted

Flagged first, then by citations

4 of the 102 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Related

Authors
Schirrmeister, B. E., Gugger, M., & Donoghue, P. C. J.
Affiliations
  • University of Bristol (GB)
  • Institut Pasteur (FR)
ORCID
Venue
Palaeontology
Publisher
Wiley
Published
2015-06-23
Volume
58
Issue
5
Pages
769-785
ISSN
  • 0031-0239 (ISSN-L)
  • 1475-4983
DOI
10.1111/pala.12178
PMC
PMC4755140
OpenAlex
W1831957949
Semantic Scholar
6e03cd37924a78a193bde6f1580e42699eee46c3
Cited by
304
References
102
Citations by year
2026: 24 · 2025: 29 · 2024: 54 · 2023: 31 · 2022: 30 · 2021: 25 · 2020: 21 · 2019: 32 · 2018: 28 · 2017: 18 · 2016: 8 · 2015: 4
FWCI
8.40
Type
journal article
Language
en
Update notices
correction (2015-08-14)
Open access
Licence
Locations
  • Palaeontology (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Explore Bristol Research (publishedVersion, cc-by)
  • HAL (submittedVersion, cc-by)
  • Bristol Research (University of Bristol) (submittedVersion, cc-by)
Funders
  • Biotechnology and Biological Sciences Research Council (BB/J00538X/1)
  • European Commission (FP7 - PEOPLE - 2012 - IEF) (PIEF-GA-2012-330849)
  • Swiss National Science Foundation (PBZHP3_147232)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protist diversity and phylogeny
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Photosynthetic Processes and Mechanisms
Keywords
cyanobacteria, Great Oxidation Event, multicellularity, cyanobacterial evolution, Archean, phylogenomics, character reconstruction, cyanobacterial genome, cyanobacterial diversity

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-08.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-08.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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