What type of mutation results in the loss of a DNA segment?

A deletion mutation occurs when a segment of DNA is lost or removed. This type of mutation can lead to significant changes in the genetic sequence, as the deletion can involve one or several nucleotides. When a DNA segment is deleted, the sequence of nucleotides that codes for specific proteins is altered, which can disrupt normal biological functions.

Deletion mutations can have various effects on the organism, ranging from benign to harmful, depending on the role of the deleted segment in the overall genetic code. For example, if the deleted segment contains essential genes or regulatory elements, the consequences can be significant, leading to diseases or developmental problems.

In contrast, other types of mutations such as substitution, insertion, and frameshift do not specifically involve the loss of a segment of DNA. A substitution mutation replaces one nucleotide with another, an insertion mutation adds one or more nucleotides to the DNA sequence, and a frameshift mutation results from insertions or deletions that alter the reading frame of the genetic code but does not exclusively refer to the loss of DNA segments. Therefore, the distinction of a deletion mutation as one that causes the loss of a DNA segment is what makes it the correct answer.