Practice question

Allele-specific oligonucleotide hybridization discriminates wild-type and mutant alleles based on thermal stability of perfect versus mismatched duplexes. A short probe complementary to one allele hybridizes strongly only under stringent conditions when the target sequence matches completely. Detection of mutation becomes possible when hybridization signals differ between probes representing alternative alleles, indicating presence, absence or heterozygosity. Skipping PCR would reduce sensitivity, and Southern blot is not essential. Requirement centers on differential signal intensity reflecting sequence complementarity, allowing precise genotyping of point mutations like sickle cell variants.