Week 10: Cold war and détente

The genetics of hyphal fusion and rejection — het loci, anastomosis, and the one week where the diplomatic label comes closest to literal.

TB0815 · diorama S. Brandt, NHM Basel · CC BY 4.0

Dispatch 10

Date: 26 April 2027
Metaphor: Cold war and détente — sustained non-aggression punctuated by rare, careful cooperation
Phenomenon: Vegetative incompatibility (het-locus recognition) preventing hyphal fusion between incompatible fungal genets, versus fusion between compatible ones

Outline

when two hyphae from the same or a compatible genet meet, they can fuse (anastomose), sharing cytoplasm and nuclei
when they are incompatible, recognition genes at het loci — studied in detail in fungi such as Neurospora crassa and Podospora anserina — trigger rejection, sometimes localised cell death at the contact point, stopping fusion before it happens
read against week 7: this is a finer-grained, genetically specified version of the same border question — not just who wins a patch of soil, but who is permitted to merge with whom at all
why “détente” is the closest of this semester’s borrowed terms to literal: fusion is a real, bounded cooperative event between otherwise separate individuals, gated by an identifiable recognition mechanism — closer to an actual détente than most of this course’s metaphors get to be