nigma
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https://phys.org/news/2019-08-thyroid-hormone-vision-zebrafish-potentially.html
The study exposed zebrafish embryos and larvae to greater levels of an active form of thyroid hormone (T3). In those zebrafish, the number of cones that expressed the red-sensitive opsin gene increased with the dosage of T3. Alternatively, if the thyroid gland was removed, the number of cones expressing orange-sensitive opsin increased compared to normal zebrafish. The findings indicate thyroid hormone can control whether red- or orange-sensitive opsin genes are turned on in zebrafish, Mackin said, a process that's not random.
Although individual cones usually produce only one type of opsin, the team found larvae exposed to T3 had individual cones that switched from triggering the orange-sensitive to the red-sensitive opsin gene. This finding suggests cones can change the type of opsins they produce. The authors suggest zebrafish may use thyroid hormone to tweak their eyesight as they grow and change their swimming and feeding behaviors.
Although individual cones usually produce only one type of opsin, the team found larvae exposed to T3 had individual cones that switched from triggering the orange-sensitive to the red-sensitive opsin gene. This finding suggests cones can change the type of opsins they produce. The authors suggest zebrafish may use thyroid hormone to tweak their eyesight as they grow and change their swimming and feeding behaviors.
