The myostatin gene has three exons and two introns. The precursor form of the protein is 335 amino acids long. The final form is a glycoprotein. Caden and Jaden have a G to A point mutation near the end of the first exon near the first intron (figure 6). This mutation alters splicing of the introns out of the mRNA in a way that lengthens the mRNA transcribed from exon 1 and produces a nonsense mutation in exon 2. The result: the gene doesn’t work, the muscles do not produce myostatin, and they overgrow.
11. Explain why all known myostatin mutations that cause double muscling are nonsynonymous (change the encoded amino acid sequence) rather than synonymous (do not change the amino acid sequence).
12. Do you think that someone who is extra strong due to a myostatin mutation should be considered to have an unfair advantage in athletic competition?
13. Suggest a medical treatment that would involve the use of myostatin.