Why do mammals , including humans, have a single row of teeth while other animals such as sharks display up to five rows of teeth ? According to American researchers at the University of Rochester Medical Center, the key is in the genes.
To prove this, the researchers created a mutant mouse that lacked the Osr2 transcription factor, and found that the mice grew extra teeth that were not in line with the rest. The authors claim that it is the first gene identified unique to mammals that limits the shape and location of teeth . And they believe it works in opposition to other known proteins, called Bmp4 and Msx1 , which according to previous studies stimulate tooth growth. "It takes hundreds of genes to make a single tooth, so we were surprised to find that deleting just one of them activates a totally new dental training program," says geneticist and study co-author Rulang Jiang.
The researchers assure that they will advance their studies, from which interesting medical applications could be derived in the future.
