What is it about?

Thyroid hormone is best known for regulating metabolism. We have discovered a role for the hormone in determining the structure of fish fin rays. Thyroid hormone is needed to shape the bony rays along the axis of the fin during both development and regeneration.

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Why is it important?

Half of all living vertebrates are fish, and fish show great diversity in the structure and patterning of their fin rays. We have shown that thyroid hormone orchestrates the precise patterning of the fin rays, and across diverse species, the hormone helps regulate the shapes of ray segments and location of branches on the rays. This work suggests targets that may have been modulated during evolution to change the overall form of fin rays during the adaptation of different fishes.


The novel shape of the fin rays in hypothyroid zebrafish was originally discovered by a talented undergraduate in my lab, whose discovery set the lab on an exciting research trajectory. This publication is the culmination of many years of work and the efforts of scientists at numerous career stages (undergrad through postdoc). I hope that this research gives people a new appreciation for both thyroid hormone and the beauty of fish fins.

Sarah McMenamin
Boston College

Read the Original

This page is a summary of: Thyroid hormone regulates proximodistal patterning in fin rays, Proceedings of the National Academy of Sciences, May 2023, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2219770120.
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