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DTSTAMP:20260405T153412Z
UID:612f3252ab264230770596@ist.ac.at
DTSTART:20210929T123000
DTEND:20210929T133000
DESCRIPTION:Speaker: Michael Turelli\nhosted by Nick Barton\nAbstract: Cyto
 plasmic incompatibility (CI) is the most common reproductive manipulation 
 produced by Wolbachia\, obligately intracellular alphaproteobacteria that
  infect roughly half of all insect species. Once infection frequencies wit
 hin host populations approach 10%\, intense CI can drive Wolbachia to ne
 ar fixation within 10 generations. However\, natural selection among Wolb
 achia variants within individual host species does not favor enhanced CI.
  Indeed\, variants that eliminate CI\, but increase host fitness\, are exp
 ected to spread (Turelli 1994). Nevertheless\, roughly half of Wolbachia
  infections cause detectable CI. What selects for and maintains this phen
 otype? CI-causing Wolbachia variants preferentially spread into new host
  species because\, as simple models show\, CI increases equilibrium popula
 tion frequencies and CI-causing variants can be maintained at high frequen
 cies even if conditions fluctuate so that initially beneficial Wolbachia
  infections become deleterious to their hosts. In contrast\, CI does litt
 le to help establish beneficial Wolbachia in new host species. An epidem
 iological model that describes Wolbachia gain and loss by host species a
 nd the loss of CI within Wolbachia lineages yields simple expressions fo
 r the frequency of Wolbachia-infected species and the fraction of those i
 nfections that cause CI. CI exemplifies a common phenotype whose frequency
  and persistence is more plausibly explained by enhancing spread to new ho
 st lineages rather than enhancing spread within host lineages (i.e.\, clas
 sical natural selection). Data documenting recent Wolbachia acquisitions
  by many hosts species\, suggesting ongoing spatial spread within host spe
 cies\, and rapid evolution (especially degradation) of CI-causing loci sup
 port a determinative role for interspecific transmission in maintaining CI
 .  
LOCATION:I22 Lakeside View (I22.O1.006)\, ISTA
ORGANIZER:abonvent@ist.ac.at
SUMMARY:Michael Turelli: Why is Wolbachia-induced cytoplasmic incompatibili
 ty so common?
URL:https://talks-calendar.ista.ac.at/events/3312
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