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.
This mutation occurs when insertions and deletions alter a gene so that its message is no longer correctly parsed. Effects are one of the following: 1) No effect if the mutated codon still codes for the same amino acid. 2) It can result in the protein having one different amino acid.