In:
eLife, eLife Sciences Publications, Ltd, Vol. 5 ( 2016-07-12)
Abstract:
The pioneering eye doctor André Rochon-Duvigneaud once wrote that “a bird is a wing guided by an eye”. With this statement, he underscored the sophistication of the bird’s eye, which surpasses our own in several respects. Compared to humans who have three types of cone photoreceptor, birds have four, meaning they can see an extra dimension of color. Birds precisely tune their violet-, blue-, green- and red-sensitive cones by coupling light-sensitive proteins with light-filtering pigments called carotenoids. This combination of sensors and filters increases the number of colors a bird can see. Another exceptional aspect of bird vision is that some species – for example finches and sparrows – can see ultraviolet (UV) light. This ability results from a change in the light-sensitive protein within the violet cone photoreceptor that shifts its sensitivity towards UV light. This expansion of vision into the UV is complemented by a shift in the sensitivity of the blue cone photoreceptor. However, it is not well understood exactly how the sensitivity of the blue cone is shifted and how this shift impacts color vision. To find answers to these questions, Toomey et al. characterized the light-filtering carotenoid pigments from bird species with violet or UV sensitivity, and used computational models of bird vision to predict how these pigments affect the number of colors a bird can see. This approach revealed that blue cone sensitivity is fine-tuned through a change in the chemical structure of the light-filtering carotenoid pigments within the photoreceptor. Computational models also indicated the sensitivity of the violet and blue cones must shift in a coordinated manner to maximize the number of colors a bird can see. These results suggest that both blue and violet cone cells have been fine-tuned during evolution to enhance color vision in birds. An important next step is to investigate the underlying molecular mechanisms that coordinate the modification of the carotenoid pigments and the tuning of light-sensitive proteins in a wide range of bird species.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.15675.001
DOI:
10.7554/eLife.15675.002
DOI:
10.7554/eLife.15675.003
DOI:
10.7554/eLife.15675.004
DOI:
10.7554/eLife.15675.005
DOI:
10.7554/eLife.15675.006
DOI:
10.7554/eLife.15675.007
DOI:
10.7554/eLife.15675.008
DOI:
10.7554/eLife.15675.009
DOI:
10.7554/eLife.15675.010
DOI:
10.7554/eLife.15675.011
DOI:
10.7554/eLife.15675.012
DOI:
10.7554/eLife.15675.013
DOI:
10.7554/eLife.15675.014
DOI:
10.7554/eLife.15675.015
DOI:
10.7554/eLife.15675.016
DOI:
10.7554/eLife.15675.017
DOI:
10.7554/eLife.15675.018
DOI:
10.7554/eLife.15675.019
DOI:
10.7554/eLife.15675.020
DOI:
10.7554/eLife.15675.021
DOI:
10.7554/eLife.15675.022
DOI:
10.7554/eLife.15675.023
DOI:
10.7554/eLife.15675.024
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2016
detail.hit.zdb_id:
2687154-3
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