Which polymorphism involves variation of a single base pair?

The correct answer is based on the definition of single-nucleotide polymorphism (SNP). A single-nucleotide polymorphism is a variation at a single position in a DNA sequence among individuals. SNPs can occur in coding and non-coding regions of the genome and can affect gene function, regulation, and contribute to the variability found in traits among populations.

SNPs are the most common type of genetic variation in humans and can be crucial for understanding genetic predispositions to diseases and responses to drugs. They can act as markers in genetic studies and are used extensively in genome-wide association studies to investigate associations with various phenotypes.

In contrast, chromosomal polymorphism refers to variations in the structure or number of chromosomes, which is a broader category than just a single base change. DNA polymorphism can include various types of variations, not limited to single base changes, and gene duplication specifically involves the replication of entire sections of DNA sequences rather than individual base pairs. Therefore, single-nucleotide polymorphism is distinct because it specifically addresses the consequence of a single base pair change within the genome.