Biology 1002B Lecture Notes - Lecture 25: Cone Cell, Pax6, Opsin
16 Aug 2017
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Cycle 12 lecture 25: evolution of colour vision. Many animals have eyes (jellyfish, octopus, insects, vertebrates) Independent evolution of eye at least 40 times: tissue recruited to make the eye and structure of the eye is different, harvest and focus light in fundamentally different ways. Huge selective advantage for an organism to perceive its environment. Not homologous: similarity =/= used to be same gene in common ancestor. Family of highly related transcription factors crucial in embryonic development. Specifically involved in development of sensory organs (including eye): activate developmental pathway that leads to formation of the eye early in embryonic development, everything that has an eye has pax6. Homology: originated before major divisions of animals. If you align pax6 sequences from very divergent animals, they align very well with major domains linked to function. Cone cell / photoreceptor cell is a cell and with millions of rhodopsin molecules. 3 different classes of rhodopsin in eye.
