NEET2026BiologyChapterActual
During a molecular diagnostic procedure, a single-stranded DNA tagged with a radioactive molecule is used to screen a patient's cell clones for a suspected genetic disorder. The probe is designed to match the normal, healthy allele. After allowing hybridization and performing autoradiography, what will be the outcome for a clone that possesses the mutated allele?
Options
- AIt will be clearly visible on the X-ray film because the mutation enhances the binding affinity of the probe.
- BIt will not be recorded on the photographic film since the probe cannot establish complementary base pairing w
- CIt will appear as a faint signal on the film due to the probe hybridizing with the RNA transcripts of the muta
- DIt will be detected successfully because the radioactive molecule emits radiation regardless of whether hybrid
Correct answer
B. It will not be recorded on the photographic film since the probe cannot establish complementary base pairing w
Step-by-step solution
A single-stranded DNA or RNA tagged with a radioactive molecule (probe) is allowed to hybridize to its complementary DNA in a clone of cells. This is followed by detection using autoradiography. The probe is designed to be complementary to the normal, healthy allele. If the clone possesses a mutated allele, the sequence is altered. Consequently, the probe will not have complementarity with the mutated gene and will fail to hybridize. Since the radioactive probe does not bind to the mutated sequence, it will be wash