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endosymbiosis

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77 items with this tag.

Nov 04, 2026
LIT-2001: The Major Transitions in Evolution
Nov 01, 2026
LIT-1929: Three Problems for the Mutual Manipulability Account of Constitutive Relevance in Mechanisms
Oct 30, 2026
CLAIM-506: The split of the last eukaryotic common ancestor's central carbon metabolism, archaeal enzymes in the cytosol and alphaproteobacterial ones in the mitochondrion, does not single out syntrophy: a host that kept its own archaeal glycolysis and took up a bacterium with a TCA cycle leaves it whether the partnership began in syntrophy or by engulfment by an already complex host, and what the split counts against is a host whose carbon metabolism was replaced by the symbiont's
- endosymbiosis
- natural-sciences
Oct 30, 2026
CLAIM-508: Gene ancestries alone cannot tell a symbiotic partner from a source of transferred genes: a partner whose genes were mostly lost, replaced or spread thin would leave the diffuse trace that Tobiasson and colleagues read as piecemeal transfer, and Bernabeu and colleagues concede that their donor signals say nothing of the kind of interaction
- endosymbiosis
- natural-sciences
Oct 30, 2026
CLAIM-509: Stem lengths alone do not establish an order of acquisition in eukaryogenesis, neither Pittis and Gabaldón's late mitochondrion nor Bernabeu and colleagues' transfer waves: normalized stem length measures time only if rates before and after LECA are proportional, it shortens as closer relatives are sampled, the alphaproteobacterial separation from other bacteria rests on P = 0.044, and on Tobiasson and colleagues' data it does not behave as a clock
- endosymbiosis
- natural-sciences
Oct 30, 2026
QUESTION-353: Across real symbioses, does the partner with the larger and faster-growing population become obligate first more often than chance, and does the other partner's dependence follow the balance of births and deaths inside the collective, as Athreya, Czuppon and Gokhale's model predicts?
- endosymbiosis
- individuation
Oct 30, 2026
THEORY-1197: Eukaryogenesis involved one archaeal host lineage, of Asgard descent, and one bacterial endosymbiont, the alphaproteobacterial ancestor of mitochondria; the eukaryotic genes from other bacteria came by piecemeal gene transfer, not from further symbiotic partners
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1200: The Asgard archaeal ancestor of eukaryotes depended on metabolic partners: like Candidatus Prometheoarchaeum syntrophicum, it degraded amino acids in syntrophy, handing hydrogen and formate to partners that removed them
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1201: Normalized stem length is not a clock of gene acquisition time: it is set mainly by factors other than when a gene was acquired, such as adaptation to the new cell after acquisition, so relative timings of eukaryogenesis drawn from stem lengths alone are not supported
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1203: The host lineage elaborated its cytoskeleton, endomembrane system and nuclear machinery before mitochondrial endosymbiosis began, about 2.2 billion years ago: most pre-LECA duplications in eukaryotic gene families of archaeal origin predate it
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1205: Eukaryotes began in a syntrophic partnership: an archaeal host fermented sugars and passed reducing equivalents to an alphaproteobacterial endosymbiont that contributed a TCA cycle and an electron transport chain, which is why the last eukaryotic common ancestor's central carbon metabolism is archaeal in cytosolic glycolysis and the pentose phosphate pathway and alphaproteobacterial in the mitochondrial TCA cycle
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1206: The mitochondrion was acquired late in eukaryogenesis, by a host whose proteome was already chimaeric, with genes from several bacterial sources acquired before it
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1208: Bacterial endosymbionts lose their cell-envelope and envelope-transport genes together below about 400 kb and begin to lose translation genes below about 200 kb, and the host supplies the membranes, transport and protein synthesis that the smallest-genome symbionts no longer encode, as for organelles
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1211: An endosymbiont becomes an organelle in steps: the host first targets effector proteins into it; an imported host protein redundant with one of its functions then lets the endosymbiont's own gene decay, making it dependent; and a general import pathway, once evolved, brings in hundreds of proteins; this genetic integration arises only in permanent, vertically transmitted associations
Oct 30, 2026
THEORY-1214: Cicada hosts whose endosymbiont Hodgkinia has split into many interdependent lineages compensate by sending more Hodgkinia cells to each egg, with Sulcia numbers and the transmission route unchanged, so that every egg still receives every lineage; the raised titre is a host adaptation driven by the symbiont's fragmentation, and a cost of it
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1215: Besides Asgard archaea and the alphaproteobacterial ancestor of mitochondria, Myxococcota and Planctomycetota were major donors of genes to the eukaryotic lineage before its last common ancestor, in waves: Asgard first, then Planctomycetota before the mitochondrion, then the mitochondrial ancestor and Myxococcota together
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1219: Buchnera's metabolism interlocks with its aphid host's: it makes the essential amino acids its host cannot from host-supplied glutamate and aspartate, depends on the host for the non-essential amino acids and its membrane phospholipids, and cannot live outside the bacteriocyte
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1223: Monocercomonoides exilis lost its mitochondrion only after the organelle's essential functions had been removed in steps, Fe–S cluster assembly to a cytosolic SUF system and then the glycine cleavage system by loss, and the loss required no compensating change elsewhere in the cell
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1228: A bacterial endosymbiont becomes genetically integrated, an organelle, when host proteins imported into it replace genes it has lost, and this does not require gene transfer from the endosymbiont: in the Paulinella chromatophore and the nitroplast, the two systems with hundreds of imported proteins, the replacing genes are mostly the host's own or come from other bacteria
- endosymbiosis
- natural-sciences
Oct 30, 2026
THEORY-1235: Losing a costly function whose product leaks to neighbours is favoured by ordinary individual selection in large free-living microbial populations, and the loss proceeds until the remaining producers just supply the community, so that most cells come to depend on a rare few with no relatedness, cooperation or collective required
- endosymbiosis
- ecology
Oct 30, 2026
THEORY-1243: In incipient endosymbioses in nature, mutual dependence evolves ahead of reproductive cohesion, so that endosymbioses are more likely to be mutually dependent than cohesive
- endosymbiosis
- individuation
Oct 27, 2026
CASE-167: The nitroplast: UCYN-A, a streamlined nitrogen-fixing cyanobacterium in a marine alga, whose division is coupled to the host's and which imports host-encoded proteins, reclassified as an early-stage organelle in 2024
- endosymbiosis
- individuation
Oct 27, 2026
CASE-168: Monocercomonoides: a eukaryote that lost its mitochondrion entirely after the organelle's essential jobs were removed in steps, its Fe–S cluster assembly taken over by a bacterial-type SUF system that its relatives share and its glycine cleavage system lost, and kept canonical eukaryotic complexity
- endosymbiosis
- individuation
Oct 27, 2026
CASE-171: Mealybugs, Tremblaya and Moranella: a bacterium inside a bacterium inside an insect, amino-acid pathways patched together from three genomes and genes transferred from other bacteria, and an inner symbiont replaced several times while the transferred genes stayed
Oct 27, 2026
CASE-173: Aphids and Buchnera: an obligate nutritional symbiosis in which neither partner reproduces alone, and the symbiont's genome reduced to a seventh of E. coli's
Oct 27, 2026
CASE-174: Paulinella chromatophora: a photosynthetic organelle in the making, from an endosymbiosis independent of the plastids', its genome reduced to about a third of its coding capacity, and hundreds of host proteins imported into it, most encoded by the host's own genes rather than transferred from the symbiont
- endosymbiosis
- individuation
Oct 27, 2026
CASE-177: Hodgkinia in cicadas: one endosymbiont splitting into two to dozens of interdependent lineages, with near-complementary gene sets, idiosyncratic fragmentation in Magicicada, and hosts transmitting up to six times as many cells to keep every lineage
Oct 27, 2026
LIT-1557: Trafficking of protein into the recently established photosynthetic organelles of Paulinella chromatophora
Oct 27, 2026
LIT-1558: Dominant contribution of Asgard archaea to eukaryogenesis
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1559: Extreme genome reduction in symbiotic bacteria
Oct 27, 2026
LIT-1560: Protein import into bacterial endosymbionts and evolving organelles
Oct 27, 2026
LIT-1561: Gene ancestries reveal diverse microbial associations during eukaryogenesis
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1562: Nitrogen-fixing organelle in a marine alga
Oct 27, 2026
LIT-1563: Sympatric Speciation in a Bacterial Endosymbiont Results in Two Genomes with the Functionality of One
Oct 27, 2026
LIT-1564: Chimeric origins and dynamic evolution of central carbon metabolism in eukaryotes
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1565: An Interdependent Metabolic Patchwork in the Nested Symbiosis of Mealybugs
Oct 27, 2026
LIT-1566: Dated gene duplications elucidate the evolutionary assembly of eukaryotes
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1567: A Eukaryote without a Mitochondrial Organelle
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1568: The Black Queen Hypothesis: Evolution of Dependencies through Adaptive Gene Loss
Oct 27, 2026
LIT-1569: Horizontal Gene Transfer from Diverse Bacteria to an Insect Genome Enables a Tripartite Nested Mealybug Symbiosis
Oct 27, 2026
LIT-1570: The Evolution of Dependence and Cohesion in Incipient Endosymbioses
Oct 27, 2026
LIT-1571: How do bacterial endosymbionts work with so few genes?
Oct 27, 2026
LIT-1572: Repeated replacement of an intrabacterial symbiont in the tripartite nested mealybug symbiosis
Oct 27, 2026
LIT-1573: Accelerated evolution and Muller's rachet in endosymbiotic bacteria
Oct 27, 2026
LIT-1574: The Oxymonad Genome Displays Canonical Eukaryotic Complexity in the Absence of a Mitochondrion
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1585: Chance and necessity in the evolution of minimal metabolic networks
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1586: Multiple origins of interdependent endosymbiotic complexes in a genus of cicadas
Oct 27, 2026
LIT-1588: Endosymbiotic gene transfer: organelle genomes forge eukaryotic chromosomes
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1590: Changes in Endosymbiont Complexity Drive Host-Level Compensatory Adaptations in Cicadas
Oct 27, 2026
LIT-1591: Isolation of an archaeon at the prokaryote–eukaryote interface
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1595: Late acquisition of mitochondria by a host with chimaeric prokaryotic ancestry
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1596: Genome sequence of the endocellular bacterial symbiont of aphids Buchnera sp. APS
Oct 27, 2026
LIT-1597: The hydrogen hypothesis for the first eukaryote
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1602: Idiosyncratic Genome Degradation in a Bacterial Endosymbiont of Periodical Cicadas
Oct 27, 2026
LIT-1605: Host Control of Symbiont Transmission: The Separation of Symbionts Into Germ and Soma
- endosymbiosis
- ecology
Oct 27, 2026
LIT-1611: The consequences of genetic drift for bacterial genome complexity
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1612: Genome expansion via lineage splitting and genome reduction in the cicada endosymbiont Hodgkinia
Oct 27, 2026
LIT-1616: Deletional bias and the evolution of bacterial genomes
- endosymbiosis
- natural-sciences
Oct 27, 2026
LIT-1617: Host–symbiont conflict over the mixing of symbiotic lineages
- endosymbiosis
- ecology
Oct 27, 2026
LIT-1621: Chromatophore Genome Sequence of Paulinella Sheds Light on Acquisition of Photosynthesis by Eukaryotes
- endosymbiosis
- natural-sciences
Oct 27, 2026
QUESTION-277: When formerly autonomous partners come to depend on one another, which of mutual dependence, reproductive cohesion, the distribution of essential functions across genomes, the host's regulatory control and the alignment of selection does each route to dependence bring about, and which of them, alone or together, make the partnership a new evolutionary individual?
Oct 27, 2026
THEORY-1048: On the Black Queen Hypothesis of Morris, Lenski and Zinser, losing a costly function whose product leaks to neighbours is favoured by ordinary individual selection in large free-living microbial populations, and the loss proceeds until the remaining producers just supply the community, so that most cells come to depend on a rare few with no relatedness, cooperation or collective required
- endosymbiosis
- ecology
Oct 27, 2026
THEORY-1049: On McCutcheon and colleagues' survey, bacterial endosymbionts lose their own cell-envelope and envelope-transport genes together below about 400 kb, and begin to lose translation genes (ribosomal proteins, tRNAs, aminoacyl-tRNA synthetases) below about 200 kb, so that the smallest-genome symbionts cannot be self-sufficient and their membranes, transport and protein synthesis are presumably supplied by the host, as for organelles
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1050: In Athreya, Czuppon and Gokhale's adaptive-dynamics model of an incipient endosymbiosis, mutual dependence (the product of the partners' obligacies) evolves ahead of reproductive cohesion (the product of their adhesions) early on, but only under the mapping in which each partner's free-living growth depends on its own obligacy alone while dissociation depends on both partners' adhesions; the authors' own appendix shows the bias vanishing under matched mappings and reversing under the opposite one, and their survey of real symbioses cannot test it
- endosymbiosis
- individuation
Oct 27, 2026
THEORY-1051: In Athreya, Czuppon and Gokhale's model of an incipient endosymbiosis, the partner with the larger and faster-growing population evolves faster and becomes fully obligate first, which the authors read as a Red King effect in which the collective's shared fate aligns interests; with equal within-collective rates for both partners, the other partner's dependence then stays where it was, rises to full dependence, or falls to none, according to whether partners are born or die inside the collective; and in its simulations dependence rose from zero at the higher collective carrying capacities tried and not at the lowest, under a condition the authors show sufficient and not necessary, so a full transition to a mutually dependent, co-reproducing pair is a parameter-dependent outcome and not the default
- endosymbiosis
- individuation
Oct 27, 2026
THEORY-1098: On Karnkowska and colleagues' genome analysis, the oxymonad Monocercomonoides exilis lost its mitochondrion only after the organelle's essential functions had been removed one by one, Fe–S cluster assembly to a bacterial-type SUF system shared with mitochondriate relatives and then the glycine cleavage system by loss, and the loss left the rest of the cell canonical, with no compensating changes found
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1099: On Kay and colleagues' relaxed-clock dating of pre-LECA gene duplications, most duplications in eukaryotic gene families of archaeal origin, including actin, tubulin, vesicle-trafficking and nuclear-targeted families, predate the onset of duplications in genes of alphaproteobacterial origin at about 2.2 billion years ago, which the authors take as the start of mitochondrial endosymbiosis, so the host was elaborating its cytoskeleton, endomembranes and nuclear machinery before the mitochondrion; each date is a maximum age for its paralogues' functions, many intervals reach below 2.2 billion years, and the order of phagocytosis and the mitochondrion is left open
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1100: On Sørensen and colleagues' review, a bacterial endosymbiont becomes genetically integrated, the authors' mark of an organelle, when nuclear genes whose products are imported into it functionally replace essential genes it has lost, and this does not require gene transfer from the endosymbiont: in the Paulinella chromatophore and the nitroplast, the two systems with hundreds of imported proteins, many of which fill gaps left by lost genes, the imported proteins come mostly from the host's own genes or from other bacteria, and in the nitroplast no gene transfer from the endosymbiont has been found
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1101: Tobiasson, Luo, Wolf and Koonin find, on 5,850 eukaryotic gene stems, that normalized stem length does not behave as a clock of acquisition time: alphaproteobacterial stems are longer than Asgard ones for the 70% of stems below 0.3 and shorter only above 0.35, oxidative-phosphorylation genes presumed acquired together vary by more than two orders of magnitude, and information-processing genes have short stems; they conclude that even normalized stem lengths are set primarily by factors other than acquisition time, at least over the long timescales analysed, and suggest that adaptation after acquisition lengthens stems
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1102: On Pittis and Gabaldón's stem-length analysis of the LECA proteome, families of alphaproteobacterial origin and mitochondrial location sit closer to their prokaryotic relatives, after correction for each family's rate, than families of other bacterial origin (P = 0.044), which sit closer than archaeal families, and the authors read this as late acquisition of the mitochondrion by a host whose proteome was already chimaeric, under their stated assumption that rates before and after LECA are correlated
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1103: On Shigenobu and colleagues' genome of Buchnera sp. APS, the aphid symbiont keeps the genes for the amino acids its host cannot make and has lost almost all of those its host can, uses host-made glutamate and aspartate as precursors, and lacks phospholipid synthesis and nearly all its own transcriptional regulators, so that its metabolism interlocks with the host's and it presumably lives only inside the bacteriocyte, a state reached by gene loss from an E. coli-like ancestor
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1104: In Tobiasson, Luo, Wolf and Koonin's constrained-tree survey of widespread eukaryotic protein families, Asgard archaea are the largest single prokaryotic source, with about half the likelihood weight in the best-resolved families and the lead in nearly every functional system, while Alphaproteobacteria contribute a small, coherent set centred on the mitochondrion and other bacteria about a third of families, scattered across functions with no pathway led by one donor except a narrow Myxococcota signal in nucleotide-sugar and nicotinate metabolism; the authors read this as one Asgard host lineage, one endosymbiont and piecemeal gene transfer rather than further symbioses
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1105: In Bernabeu, Manzano-Morales, Marcet-Houben and Gabaldón's reconstruction of the last eukaryotic common ancestor's proteome, two bacterial phyla besides the mitochondrial ancestor, Myxococcota and Planctomycetota, each account for a share of the proteome comparable to that of Alphaproteobacteria and Asgard archaea under thresholds calibrated on those accepted partners, and stem-length distributions order the acquisitions as waves, Asgard first, then Planctomycetota, then the mitochondrial ancestor and Myxococcota together; the authors read this as serial associations with several partners, while conceding that their data cannot say whether any donor was a symbiont
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1106: Campbell and colleagues report, from four cicada species with five or six eggs each, that Hodgkinia cells per egg range from about 4,900 in a species with one Hodgkinia lineage to about 30,000, some six times as many, in Magicicada septendecim, whose Hodgkinia has split into many interdependent lineages and the only species that differs significantly, while Sulcia numbers are not raised, the transmission route is the same, and every egg sampled carries every lineage tracked by marker genes; the authors take the raised titre as a host adaptation that compensates for the symbiont's fragmentation, and a cost of it
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1107: On Sørensen and colleagues' scenario, an endosymbiont becomes an organelle in steps: the host first targets effector proteins into it; an imported host protein redundant with one of its functions then lets the endosymbiont's own gene decay, making it dependent; and a general import pathway, once evolved, brings in hundreds of proteins; this genetic integration arises only in permanent, vertically transmitted associations, and host effector control without vertical transmission, as in rhizobia, does not lead to it
Oct 27, 2026
THEORY-1108: On Imachi and colleagues' cultivation of Candidatus Prometheoarchaeum syntrophicum MK-D1, the first Asgard archaeon grown in the laboratory is a small, internally simple coccus with long branching protrusions that degrades amino acids only in syntrophy, handing hydrogen and formate to partners that can be exchanged, and from its genome and other Asgard genomes the authors infer that the Asgard ancestor was likewise dependent on metabolic partners; the isolate is a modern relative separated from the host lineage by about two billion years, grown only in co-culture, and the entangle–engulf–endogenize model built on it is a hypothesis the authors call not definitive
- endosymbiosis
- natural-sciences
Oct 27, 2026
THEORY-1109: Santana-Molina, Williams, Snel and Spang find that the last eukaryotic common ancestor's central carbon metabolism was chimeric: a few Asgard-archaeal enzymes in cytosolic glycolysis and the pentose phosphate pathway, four placed with Asgard archaea at bootstrap 39–97% and two ambiguously, most alphaproteobacterial ones in the mitochondrial TCA cycle and pyruvate conversion, and others from various bacteria with no third dominant donor, since remodelled by loss, horizontal replacement and retargeting so that compartment no longer follows origin; the authors take the cytosol–mitochondrion split as support for syntrophy
- endosymbiosis
- natural-sciences

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