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SUMMARY:An ancient ecospecies of Helicobacter pylori found in Indigenous p
 opulations and animal adapted lineages - Professor Daniel Falush from Shan
 ghai Institute of Immunity and Infection\, Chinese Academy of Sciences 
DTSTART:20231206T140000Z
DTEND:20231206T150000Z
UID:TALK208714@talks.cam.ac.uk
CONTACT:Caroline Newnham
DESCRIPTION:The colonization of our stomachs by Helicobacter pylori is bel
 ieved to predate the oldest splits between extant human populations. We id
 entify a “Hardy” ecospecies of H. pylori associated with indigenous gr
 oups\, isolated from people in Siberia\, Canada\, and USA. The ecospecies 
 shares the ancestry of “Ubiquitous” H. pylori from the same geographic
 al region in most of the genome but has nearly fixed SNP differences in 10
 0 genes\, many of which encode outer membrane proteins and previously iden
 tified host interaction factors. For these parts of the genome\, the ecosp
 ecies has a separate\, independently evolving gene pool with a distinct ev
 olutionary history. H. acinonychis\, found in big cats\, and a newly ident
 ified primate-associated lineage both belong to the Hardy ecospecies and b
 oth represent human to animal host jumps. Most strains from the ecospecies
  encode an additional iron-dependent urease that is shared by Helicobacter
  from carnivorous hosts\, as well as a tandem duplication of vacA\, encodi
 ng the vacuolating toxin. We conclude that H. pylori split into two highly
  distinct ecospecies approximately 300\,000 years ago and that both disper
 sed around the globe with humans. Coexistence has likely been possible bec
 ause the ecospecies are adapted to different host diets\, but the Hardy ec
 ospecies has gone extinct in most parts of the world. Our analysis also pu
 shes back the likely length of the association between H. pylori and human
 s.
LOCATION:Biffen Lecture theatre and Zoom
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