Tensor tympani- The tensor tympani is the larger of the two muscles of the auditory canal, the other being stapedius. The muscle functions to dampen down sounds such as chewing. It arises from the cartilaginous portion of the eustachian tube as well as the adjacent section of the greater wing of the sphenoid bone.
A nonsense mutation in the leptin gene that results in a stop codon and lack of leptin production was first observed in mice in 1950. In the mouse gene, arginine-105 is encoded by CGA and only requires one nucleotide change to create the stop codon TGA.
For instance in sicke-cell disease, the 20th nucleotide of the gene for the beta chain of hemoglobin on chromosome 11 is changed from the codon GAG to GTG so that when translated the 6th amino acid is now a valine in stead of glutamic acid. Compare: nonsense mutation, silent mutation.