For over 150 years scientists and researchers have been trying to unlock the mystery that surrounds teeth and birds. However, that mystery has now been solved. Going back to one of the modern-day-bird’s earliest ancestors the Archaeopteryx had a set of teeth. Scientists then wondered whether the teeth stopped growing independently of each other or if there was a common thread in bloodline that would have caused all birds thereafter to be absent of teeth.
Scientists have learned though that it was likely due to the common thread in their bloodline. Roughly 116 million years ago, scientists believe that a single ancestor lost its teeth – and from there the rest of birds afterward were absent of teeth. Scientists and researchers analyzed 48 different bird species, which represented almost all orders of the modern-day bird and what they found was that the same mutations were found in each – leading scientists to the common-ancestor theory.
The team learned this by investigating the six genes that ultimately are responsible for tooth production in birds. These six genes are the ones responsible for creating dentin and enamel in teeth that are found in vertebrates. Enamel is the hard coating found on the outside of teeth, and dentin is the stuff that fills the inside of the tooth. Dentin is significantly less strong than enamel, and what the scientists found was that as the enamel stopped being produced, the existence of teeth began disappearing.
One member of the team responsible for this research pointed out that “The presence of several inactivating mutations that are shared by all 48 bird species suggests that the outer enamel covering of teeth was lost around 116 million years ago.”
These findings were just one of the many findings that were brought to light regarding the evolution of birds throughout their history.
Interestingly though, scientists did find that the closing living reptile to birds still maintain the function of all six genes that are responsible for tooth production. That living relative though, the alligator, would be incredibly hard to imagine without teeth.
The ucrtoday published the work on December 12th.