Point mutation is seen in
**Core Concept**
Point mutations refer to single nucleotide substitutions that occur in the DNA sequence, leading to changes in the amino acid sequence of a protein. This type of mutation can result in various effects on protein function, including loss of function, gain of function, or altered function. Point mutations are a common type of genetic variation that can contribute to disease.
**Why the Correct Answer is Right**
Point mutations occur due to errors during DNA replication or repair, where a single nucleotide is replaced with another. This can lead to changes in the genetic code, resulting in the synthesis of an abnormal protein. The effect of the mutation depends on the location and the type of mutation. For example, a point mutation in a gene coding for a receptor can lead to a change in the binding affinity of the receptor, affecting its function.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because point mutations are not typically associated with chromosomal deletions or duplications, which are larger-scale genetic changes.
**Option B:** This option is incorrect because point mutations do not involve the insertion or deletion of nucleotides, which would result in frameshift mutations.
**Option C:** This option is incorrect because point mutations are not typically associated with viral infections, which can result in genetic changes due to viral integration or recombination.
**Clinical Pearl / High-Yield Fact**
Point mutations can be either germline or somatic, with germline mutations being inherited and somatic mutations occurring in specific cells. Understanding the type of mutation and its location is crucial for predicting the effect on protein function and disease severity.
**Correct Answer:** C.