Practice question

Allele-specific oligonucleotide hybridization uses labeled probes complementary to wild-type and mutant alleles to genotype individuals. Under stringent conditions, perfect match hybridizes strongly while mismatched probe shows negligible signal. An individual hybridizing exclusively to mutant probe carries mutant sequence on both homologous chromosomes, indicating homozygous mutant genotype expressing disease phenotype if recessive condition is pathogenic. Heterozygous carriers bind both probes, while unaffected homozygotes bind only wild-type probe. This differential hybridization enables rapid screening for point mutations in prenatal and carrier testing.