by Leigh Cooper, University of Idaho

Exposure to thyroid hormone can alter eye function in zebrafish, a result with implications for curing color blindness and retinal degeneration in humans.

The University of Idaho study found the dosage of thyroid hormone in zebrafish could switch the type of opsin—proteins that support color vision—produced in individual eye cells called cones, likely influencing the animals’ color vision. Zebrafish and humans have similar genetics when it comes to color vision.

The researchers’ findings were published today in Proceedings of the National Academy of Sciences and could lead to new therapies for visual disorders.

Cones distinguish color in vertebrates. Individual cones are sensitive to different colors of light depending on the type of opsin protein the cone produces. A cone that produces red-sensitive opsin is mainly responsive to red light. In humans and other primates, the genes that determine if a cone produces red- or green-sensitive opsin sit next to each other on the X chromosome.

Whether a cone became red- or green-sensitive was thought to be a random process due to this configuration. Recent research has suggested otherwise, said Robert Mackin, a doctoral student in U of I’s College of Science and lead author of the study.

“Red and green are the most important colors we see,” Mackin said. “They allow for our high-acuity vision, which we use for driving and reading. The red and the green cones that allow us to see these colors can die through diseases like macular degeneration, which affects many of the elderly.”…

Read more: https://phys.org/news/2019-08-thyroid-hormone-vision-zebrafish-potentially.html

Source: Phys ORG

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