sepia fish turtle octopus. “ to suppose that the eye with all its inimitable contrivances for...
TRANSCRIPT
Sepia
Fish
Turtle
Octopus
“ “ To suppose that the eye with all its inimitable contrivances To suppose that the eye with all its inimitable contrivances
for adjusting the focus to different distances, for admitting for adjusting the focus to different distances, for admitting
different amounts of light, and for the correction of spherical different amounts of light, and for the correction of spherical
and chromatic aberration, could have been formed by natural and chromatic aberration, could have been formed by natural
selection, seems, I freely confess, absurd in selection, seems, I freely confess, absurd in
the highest degree.”the highest degree.”
Organs of extreme perfectionOrgans of extreme perfection
Darwin 1882
“ “ Reason tells me, that if numerous gradations from a Reason tells me, that if numerous gradations from a
simple and imperfect eye to one complex and perfect can simple and imperfect eye to one complex and perfect can
be shown to exist, each grade being useful to its possessor, be shown to exist, each grade being useful to its possessor,
as is certainly the case; if further, the eye ever varies and as is certainly the case; if further, the eye ever varies and
the variations be inherited, as is likewise certainly the case the variations be inherited, as is likewise certainly the case
[...] ”[...] ”
Organs of extreme perfectionOrgans of extreme perfection
Darwin 1882
“ “ [...] and if such variations should be useful to any animal [...] and if such variations should be useful to any animal
under changing conditions of life, then the difficulty of under changing conditions of life, then the difficulty of
believing that a perfect and complex eye could be formed believing that a perfect and complex eye could be formed
by natural selection, though insuperable by our imagination, by natural selection, though insuperable by our imagination,
should not be considered as subversive of the theory. ”should not be considered as subversive of the theory. ”
Organs of extreme perfectionOrgans of extreme perfection
Darwin 1882
“ “ The simplest organ which can be called an The simplest organ which can be called an
eye consists of an optic nerve, surrounded by eye consists of an optic nerve, surrounded by
pigment-cells and covered by translucent skin, pigment-cells and covered by translucent skin,
but without any lens or other refractive body ”but without any lens or other refractive body ”
Organs of extreme perfectionOrgans of extreme perfection
Darwin 1882
Planaria torvaPlanaria torva
Gehring 2002
OriginsOrigins
Polyphyletic Polyphyletic Multiple originsMultiple origins
Monophyletic Monophyletic Single originSingle origin
OriginsOrigins
Polyphyletic Polyphyletic Multiple origins Multiple origins > 40> 40
Monophyletic Monophyletic Single originSingle origin
DesignsDesigns
Fernald 2000
Vertebrate Arthropod Cephalopod Polychaete
DesignsDesigns
Fernald 2000
OriginsOrigins
Polyphyletic Polyphyletic Multiple originsMultiple origins
Monophyletic Monophyletic Single originSingle origin
Gehring & Ikeo 1999
Gehring & Ikeo 1999
HumanHuman Aniridia Aniridia
MouseMouse Small eye Small eye
Fruit flyFruit fly Eyeless Eyeless
Pax6Pax6
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Paired Box domainPaired Box domain
Gehring & Ikeo 1999
HomeodomainHomeodomain
Gehring & Ikeo 1999
Pax6Pax6
Gehring & Ikeo 1999
Ball et al. 2002
Pax FamilyPax Family
EctopicEctopic eyeless eyeless
EctopicEctopic eyeless eyeless
Gehring 2002
Ectopic mouseEctopic mouse Pax 6 Pax 6
Gehring 2002
LegAntenna
Gehring & Ikeo 1999
MorphologyMorphology Photopigment stored in Photopigment stored in
apical microvilli apical microvilli
PhotopigmentPhotopigment r-opsin r-opsin
Transcription factorsTranscription factors Pax6, ath, brn3, BarH1 Pax6, ath, brn3, BarH1
Signaling pathwaySignaling pathway phosphodiesterase phosphodiesterase
G-proteinG-protein G Gq-subunitq-subunit
DistributionDistribution invertebrate eyes invertebrate eyes
vertebrate retinal ganglion vertebrate retinal ganglion
Rhabdomeric PRCsRhabdomeric PRCs
Arendt et al. 2004
MorphologyMorphology Photopigment stored in Photopigment stored in
membranous folds of cilium membranous folds of cilium
PhotopigmentPhotopigment c-opsin c-opsin
Transcription factorsTranscription factors rx rx
Signaling pathwaySignaling pathway phosphodiesterase phosphodiesterase
G-proteinG-protein transducin/G transducin/Gi-subuniti-subunit
DistributionDistribution vertebrate eyes & pineal vertebrate eyes & pineal
invertebrate brain invertebrate brain
Ciliary PRCsCiliary PRCs
Arendt et al. 2004
Vertebrate Arthropod Cephalopod Polychaete
DesignsDesigns
Fernald 2000
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Platynereis dumeriliiPlatynereis dumerilii
Platynereis dumeriliiPlatynereis dumerilii
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Platynereis dumeriliiPlatynereis dumerilii
Larval
Adult
Arendt et al. 2004
OpsinsOpsins
Arendt et al. 2004
OpsinsOpsins
Arendt et al. 2004
OpsinsOpsins
Arendt et al. 2004
r-opsinr-opsin
Arendt et al. 2004
c-opsinc-opsin
Arendt et al. 2004
rxrx
Arendt et al. 2004
bmalbmal
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