NEETZoologyBiotechnology and Its Applications
A molecular biologist uses a standard radioactive probe, which is complementary to a normal (wild-type) gene, to screen a patient's cell clone for a suspected cancer-causing mutation. After allowing the probe to hybridize with the cellular DNA, autoradiography is performed. The resulting photographic film shows clear and distinct radioactive spots corresponding to the clone. What does this observation indicate about
Options
- AThe cells contain the normal, unmutated gene, as the probe successfully hybridized with it.
- BThe cells contain the mutated cancer-causing gene, which actively bound to the radioactive probe.
- CThe probe failed to undergo hybridization, causing the unbound radioactive material to expose the film.
- DThe cells lack the target gene entirely, allowing the probe to precipitate and form spots.
Correct answer
A. The cells contain the normal, unmutated gene, as the probe successfully hybridized with it.
Step-by-step solution
In molecular diagnosis using autoradiography, a standard radioactive probe is designed to be complementary to the normal (wild-type) gene. If the photographic film shows clear radioactive spots, it indicates that the radioactive probe has successfully hybridized with the DNA in the cell clone. This successful hybridization proves that the cells possess the normal, unmutated gene sequence that is complementary to the probe. If the gene were mutated, it would lack complementarity with the standard probe, hybridizatio