Which type of mutation specifically affects only a single nucleotide position within a gene or genome sequence and may result in substitution, insertion, or deletion of one base?

Introduction / Context:
Mutations can range from single base changes to large chromosomal rearrangements. Single nucleotide changes are among the most common and impactful forms, influencing coding sequences, regulatory elements, and splicing signals. Recognizing the standard term for these events is essential for reading literature and lab reports.

Given Data / Assumptions:

• The mutation affects only one nucleotide position.
• Possible outcomes include base substitution, or occasionally single base insertion or deletion.
• Naming follows widely accepted genetic terminology.

Concept / Approach:
A point mutation is a change at a single nucleotide position. Subtypes include transitions and transversions for substitutions, as well as single nucleotide insertions and deletions that can cause frameshifts if they occur within coding sequences. The term excludes multi nucleotide regional changes and structural variants like inversions or translocations.

Step-by-Step Solution:
Confirm scope: only one base is altered. Apply the standard term in genetics for single nucleotide changes. Identify that point mutation best fits this description. Eliminate distractors that are nonstandard or overly broad.

Verification / Alternative check:
Databases such as dbSNP catalog single nucleotide polymorphisms, which are point mutations at the population level, reinforcing the terminology.

Why Other Options Are Wrong:

• Aerial mutation: not a recognized genetic term.
• Site mutation: vague and nonstandard in this context.
• Regional mutation: implies a larger affected segment, not a single nucleotide.

Common Pitfalls:
Equating point mutations only with substitutions; single nucleotide insertions and deletions are also often included when they affect one position.

Final Answer:
Point mutation