nucleation

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

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Properties5
StatusProposed
Tagsendosymbiosis, individuation, natural-sciences
SourceLIT-1560 — Protein import into bacterial endosymbionts and evolving organelles
ExtendsTHEORY-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
Bears onQUESTION-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?

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Source

Sørensen, Stiller, Kröninger & Nowack (2025), LIT-1560, read in full in NOTE-1241. The authors offer the sequence as plausible “in the light of the available, though limited, data”.

Where the evidence stands

What the paper shows, and what it does not, is THEORY-1107, Active, which this entry extends: that entry is the reading, this one the thesis. The promote_when above is THEORY-1107’s condition before the twenty-second status review promoted it, carried here unchanged, because it asks what would make the thesis true and not what the paper says.

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