Nonsense mutation

Nonsense mutation is a type of mutation that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and possibly a truncated, and often nonfunctional protein product. This type of mutation can affect the function of the protein and thus the phenotype of the organism.

Causes

Nonsense mutations can be caused by a variety of factors, including errors in DNA replication, exposure to mutagens, or errors in DNA repair mechanisms. They can occur in any part of the gene, but are most harmful when they occur in the early part of the gene sequence, as this can result in a severely truncated protein.

Effects

The effects of nonsense mutations can vary widely, depending on the specific gene and location of the mutation. In some cases, the truncated protein may still be partially functional, or the organism may have other copies of the gene that can compensate for the loss of function. However, in other cases, the mutation can result in a complete loss of function, leading to diseases such as cystic fibrosis or Duchenne muscular dystrophy.

Detection and Treatment

Nonsense mutations can be detected using a variety of techniques, including DNA sequencing, polymerase chain reaction (PCR), and gene expression profiling. Treatment for diseases caused by nonsense mutations can involve gene therapy, in which a normal copy of the gene is introduced into the cells of the organism, or drug therapy, in which drugs are used to suppress the effects of the mutation.

See Also

• Missense mutation
• Frameshift mutation
• Silent mutation
• Point mutation

References

Nonsense mutation Resources
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