The magazine explains: "A gene is akin to a long sentence consisting of repeating patterns of those four letters (A, T, G, C); the sequence T-G-A is like a period at the end of the sentence. It tells the body where a gene ends. But sometimes the period is out of place — it has been wrongly inserted somewhere in the sentence. Thus the set of instructions to produce the muscle protein, dystrophin, isn't read in full; this causes the body to produce a defective form of dystrophin that is too short to do its job.""
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