Question

Why do mutations that cripple the mismatch repair system inevitably lead to a higher mutation rate in other genes?

a. Mutations that cripple mismatch repair accelerate production of new mutants in other genes.
b. Mutations that cripple mismatch repair prevent mutations in other genes from being created.
c. Mutations that cripple mismatch repair prevent mistakes made during transcription of other genes from being corrected.
d. Mutations that cripple mismatch repair prevent mistakes made during replication in other genes from being corrected.
e. Mutations that cripple mismatch repair prevent mistakes made during translation of other genes from being corrected.

Answer 1

Mutations in mismatch repair enzymes lead to a higher mutation rate by allowing replication errors to go uncorrected, resulting in permanent DNA sequence changes. This can adversely affect gene function and contribute to diseases and genetic diversity.

Step-by-step explanation:

Mutations that cripple the mismatch repair system inevitably lead to a higher mutation rate in other genes because the mismatch repair system is crucial for correcting errors that occur during DNA replication. When a mutation impairs the mismatch repair enzymes, these enzymes fail to correct the mistakes made when DNA is copied. This oversight results in the accumulation of errors, which manifest as permanent mutations in the genomic sequence. Once such errors become a fixed part of the DNA, they can affect the function of other genes, potentially leading to serious consequences like cancer or other genetic diseases.

Specifically, the correct answer to the student's question is that mutations that cripple mismatch repair prevent mistakes made during replication in other genes from being corrected, which is option d. Without the proper function of mismatch repair systems, the inherent high rate of errors during DNA replication goes unchecked, significantly increasing the overall mutation rate. Therefore, not only is genetic stability compromised, but this also accelerates the rate of evolutionary change, as these mutations can become the fuel for natural selection and genetic variation.