In hybrid capture, what is the primary role of alkaline phosphatase?

In hybrid capture techniques, alkaline phosphatase plays a critical role in detecting the captured hybrids. This enzyme is often conjugated to a probe that specifically binds to the target nucleic acids, which are part of the hybridization process. Once the hybridization occurs, alkaline phosphatase is used to dephosphorylate substrates, leading to a detectable signal, such as colorimetric or chemiluminescent changes. The output of this reaction allows for quantification and visualization of the hybrid complexes formed between the target and the probe. This process is essential for determining the presence and quantity of specific nucleic acid sequences in a sample.

The other options focus on functions that are not the direct role of alkaline phosphatase in hybrid capture. Amplification of hybrid signals typically refers to polymerase chain reaction (PCR) methods or similar amplification techniques used prior to or after the hybrid capture steps. Binding to RNA targets implies a different mechanism of action that does not encompass the primary function of alkaline phosphatase. Synthesis of nucleic acids is a separate process involving polymerases, and thus is not related to detection. Therefore, the answer regarding alkaline phosphatase clearly aligns with its primary role in the detection of captured hybrids.