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1000
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Abstract/Summary
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This study provides compelling evidence that the previously reported all-cone retina of a diurnal garter snake in fact contains a population of rod photoreceptors with the appearance, and presumably function, of cones. Our results suggest that the evolution of all-cone retinas occurred not through loss of rods but rather via the evolutionary transmutation of ancestral rods into more “cone-like” photoreceptors, to regain functionality that was lost during the early, possibly fossorial, origin of snakes. This study provides a better understanding of the process by which complex molecular/cellular structures and tissue types can evolve, and how, particularly for sensory systems, physiological constraints can be shaped by selective forces to produce evolutionary novelty.
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