An individual inherits two defective copies of the MLH1 gene, a protein involved in mismatch repair of DNA during its replication.What do you predict will be the consequences of deficient mismatch repair upon DNA replication?
A) The fidelity of DNA polymerase activity will be decreased.
B) Mismatched nucleotides will no longer be detected by the replication complex.
C) Ligase will not be able to repair nicks in the DNA.
D) The excision repair proteins will no longer function.
E) A higher frequency of mutations will become fixed in the newly synthesized strand.

Question

Quizplus · Accepted Answer

Deficient mismatch repair will result in a higher frequency of mutations becoming fixed in the newly synthesized strand because the replication complex will no longer recognize and correct mismatches. This can lead to accumulation of mutations and eventually result in genetic diseases such as cancer.

An Individual Inherits Two Defective Copies of the MLH1 Gene