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Record W2170502449 · doi:10.1098/rspb.2006.3531

Origin of mitochondria by intracellular enslavement of a photosynthetic purple bacterium

2006· article· en· W2170502449 on OpenAlex
Thomas Cavalier‐Smith

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

fundA Canadian funder is recorded on the work.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueProceedings of the Royal Society B Biological Sciences · 2006
Typearticle
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicPhotosynthetic Processes and Mechanisms
Canadian institutionsnot available
FundersNatural Environment Research CouncilCanadian Institute for Advanced Research
KeywordsPeriplasmic spaceInner membraneBacterial outer membraneBiologyOrganelleProtein targetingCell biologyMitochondrionTranslocase of the outer membraneMembraneMembrane proteinInner mitochondrial membraneMitochondrial membrane transport proteinBiochemistryGeneEscherichia coli

Abstract

fetched live from OpenAlex

Mitochondria originated by permanent enslavement of purple non-sulphur bacteria. These endosymbionts became organelles through the origin of complex protein-import machinery and insertion into their inner membranes of protein carriers for extracting energy for the host. A chicken-and-egg problem exists: selective advantages for evolving import machinery were absent until inner membrane carriers were present, but this very machinery is now required for carrier insertion. I argue here that this problem was probably circumvented by conversion of the symbiont protein-export machinery into protein-import machinery, in three phases. I suggest that the first carrier entered the periplasmic space via pre-existing beta-barrel proteins in the bacterial outer membrane that later became Tom40, and inserted into the inner membrane probably helped by a pre-existing inner membrane protein, thereby immediately providing the protoeukaryote host with photosynthesate. This would have created a powerful selective advantage for evolving more efficient carrier import by inserting Tom70 receptors. Massive gene transfer to the nucleus inevitably occurred by mutation pressure. Finally, pressure from harmful, non-selected gene transfer to the nucleus probably caused evolution of the presequence mechanism, and photosynthesis was lost.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.003
Threshold uncertainty score0.333

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.001
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.009
GPT teacher head0.217
Teacher spread0.208 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it