Formamide and TMAC are utilized in which assay to enhance specificity?

The correct answer highlights the role of formamide and TMAC in enhancing the specificity of the SSOP (Sequence Specific Oligonucleotide Probing) assay. In this context, these additives serve to modify the hybridization conditions of the assay. By incorporating formamide or TMAC, the melting temperature (Tm) of the DNA duplexes formed during hybridization can be altered, which improves the discrimination between closely related sequences.

Specifically, formamide acts as a denaturant, allowing higher specificity by reducing the non-specific binding of probes to unintended targets. It does this by lowering the Tm of the DNA-DNA interactions, enabling more stringent conditions for the binding of probes to their target sequences. Similarly, TMAC enhances specificity by increasing the solubility of nucleic acids and further influencing the hybridization environment, which can lead to improved results in detecting specific alleles or sequences within a complex mixture.

In contrast, other choices focus on processes (like PCR-SSP and AHG-CDC) where the role of formamide and TMAC in enhancing specificity is not relevant or not their primary purpose. For example, while PCR-SSP does involve yield improvements and annealing temperature adjustments, the use of formamide and TMAC