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The first evidence of the fact that the birds’ distant relatives had teeth was the fossils of Archaeopteryx, an ancient bird discovered in 1861. Scientists knew that our modern day birds once had teeth used to kill and chew their prey.
A new study reveals that birds lost their teeth 116 million years ago, something the scientists hadn’t known before. Researchers believe that the common bird ancestor lost its ability to produce teeth, and how exactly this happened lies in the genes of our modern birds.
In order to prove that birds lost their teeth 116 million years ago, scientists studied the genomes of 48 species of living birds and examined six genes which are known to help with the formation of teeth.
The researchers discovered that all the examined bird species have the same genetic mutation which inactivates the genes that produce tooth enamel and the dentin, a part of the tooth.
Based on these mutations, the scientists believe that the ancestors of the modern bird lost its teeth approximately 116 million years ago. Around that time birds started to develop its beaks.
Dr. Mark Springer, one of the researchers involved in the study that shows birds lost their teeth 116 million years ago, said that most likely, the teeth in ancient birds evolved into the horny beak modern birds have.
Researchers also examined the genomes from other vertebrates which have no teeth, like the pangolins and the turtle. The results were similar to the ones involving birds. The vertebrates which have no teeth are known as “edentulous”.
The researchers explained that all the genomes found in toothless vertebrates were characterized by the inactivating mutation. The gene which produces the dentin in teeth is called DSPP and it functions in vertebrates that have teeth without enamel, like the armadillo, the aardvark or the sloth. Also, these genes were found to be functional in the closest living relatives of modern birds, the American alligator.
The new study revealing that birds lost their teeth 116 million years ago was published in the Science Magazine, on December 12.
Image Source: universaljournalreview
