An Individual Inherits Two Defective Copies of the MLH1 Gene

question 114

Multiple Choice

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.

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Definitions:

Directional Selection

A type of natural selection that favors one extreme phenotype over another, causing the allele frequency to shift in one direction.

Disruptive Selection

A form of natural selection where extreme values for a trait are favored over intermediate values, potentially leading to the evolution of distinct forms within a population.

Stabilizing Selection

A type of natural selection that favors the average individuals in a population, reducing variation around the mean phenotype.

Antibiotic Resistance

The ability of bacteria to withstand the effects of antibiotics, often through genetic mutations or acquisition of resistance genes.