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SUMMARY:Sensory receptor diversity and colour vision range in butterflies 
 and diptera - Dr Mike Perry\, NYU
DTSTART:20160429T120000Z
DTEND:20160429T130000Z
UID:TALK66035@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:Butterflies use color vision extensively to navigate the natur
 al world. Their retinas are more complex than those found in Drosophila\, 
 where development and patterning has been heavily studied.  Instead of the
  eight photoreceptors found in flies\, butterflies have an additional nint
 h photoreceptor per ommatidium (“unit eye”). They also have three main
  types of ommatidia instead of the two distributed stochastically in the f
 ly retina. We set out to determine how butterflies generate increased sens
 ory receptor diversity to provide an expanded range of color vision\, and 
 how much of the retinal patterning network from Drosophila they reuse.\nWe
  show that the regulatory network that defines photoreceptor subtypes in D
 rosophila is redeployed in butterflies (Papilio xuthus and Vanessa cardui)
  to generate additional subtypes. The R7 photoreceptor marker Prospero is 
 expressed in two rather than one photoreceptors per ommatidium. In Drosoph
 ila\, a stochastic decision to express the transcription factor Spineless 
 in R7 determines which of two subtypes of ommatidia is specified. CRISPR k
 nock-out of Spineless in butterflies shows that Spineless also controls st
 ochastic choice in each of the two R7s\, suggesting a deep evolutionary co
 nservation of stochastic patterning mechanisms. Having two stochastically 
 distributed types of R7s allows for specification of three ommatidial type
 s instead of two\, which in turn allowed for the evolution and deployment 
 of additional opsins\, tetrachromacy\, and improved color vision. These ef
 forts provide evidence that our extensive knowledge of patterning in the D
 rosophila visual system applies to other groups\, and that adaptation for 
 specific visual requirements can occur through modification of this networ
 k.\n 
LOCATION:Nick Mackintosh Seminar Room\, second floor\, Department of Psych
 ology\, Downing Site\, Cambridge
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