What is the purpose of a DNA probe?

The purpose of a DNA probe is fundamentally linked to its ability to identify specific sequences of DNA. When it comes to understanding the role of different alleles in causing diseases, a DNA probe can be used to detect the presence of specific alleles that may be associated with a disease condition. By hybridizing with complementary DNA sequences, the probe can signal the presence or absence of these alleles, offering insights into genetic predispositions to certain diseases. This is critical in research and clinical settings for identifying at-risk individuals based on their genetic makeup.

In contrast, the other options relate to different applications of molecular biology techniques. Identifying pathogens involves using probes to detect infectious agents, while measuring gene expression levels often employs techniques such as quantitative PCR rather than DNA probes directly. Cloning specific DNA segments incorporates other methodologies like restriction enzymes and ligation rather than the straightforward application of DNA probes. Each of these techniques is important in genetics and microbiology, but they serve different purposes than identifying alleles responsible for diseases.