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Karly Cohen and Adam Summers in UW News on using fluorescence to observe tooth replacement rates in fish

Friday, October 29, 2021 - 10:30

One of the facts of life for humans is the replacement of baby teeth with permanent adult teeth. Whether pulled out prematurely, wiggled loose by eager hands or naturally falling out unexpectedly, this occasion marks an important milestone in the maturation process that is shared amongst all vertebrates in some form. 

Imagine, though, losing and replacing a tooth every single day. For Pacific lingcod, this isn’t some fairy tale gone wrong or the unfortunate result of dismissing dentist recommendations, and is in fact their reality. In a paper recently published in the Royal Society, researchers from the University of Washington’s Friday Harbor Laboratories assessed over 10,000 teeth in 20 fish to find a daily replacement rate of about 3%.

Using a fluorescent technique called pulse-chase, University of South Florida undergraduate Emily Carr, University of Washington Ph.D. candidate Karly Cohen and professor Adam Summers designed an experiment to track the growth of teeth in these carnivorous fish. Using this method, the researchers were able to observe tooth growth and replacement while the organisms were still alive — which is not the case for other research methods such as CT scans.

The experiment involved transporting the fish from their normal saltwater tank into a tank filled with red dye, kept at a constant temperature and covered with a black tarp to block out light. The lingcod remained in this solution for 12 hours before they were returned to the normal tank. The red dye will stick onto anything hard or mineralized, and will remain in the mineralized tissue even after the organisms are transferred out of the tank containing the dye — allowing Carr, Cohen and Summers to mark off the teeth that were present in the lingcod’s mouth during their tenure in the red dye tank.

Read the full article in the UW College of the Environment News.

Bonus: read related articles in National GeographicThe New York Times, Live Science, Smithsonian Magazine, and TRT World.

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