NEETZoologyBiotechnology and Its Applications
In a molecular diagnosis experiment, a custom radioactive probe is artificially synthesized such that it is perfectly complementary ONLY to a specific mutated cancer-causing gene sequence. This custom probe is then applied to a clone of cells obtained from a healthy individual who possesses only the normal (wild-type) gene. Following the hybridization step and autoradiography, what will be the expected outcome on the
Options
- AThe clone will appear clearly on the film because the cells are healthy and possess the normal gene.
- BThe clone will not appear on the film because the custom probe lacks complementarity with the normal gene.
- CThe clone will appear clearly on the film because radioactive probes universally bind to all cellular DNA.
- DThe clone will not appear on the film because the normal gene is dominant and suppresses the radioactive signa
Correct answer
B. The clone will not appear on the film because the custom probe lacks complementarity with the normal gene.
Step-by-step solution
Nucleic acid hybridization relies on the principle of complementarity. A probe will only bind to a DNA sequence if their base pairs are complementary. In this scenario, the custom radioactive probe is designed to be complementary only to the mutated gene sequence. The cells from the healthy individual contain only the normal (wild-type) gene, which has a different sequence. Because the custom probe lacks complementarity with the normal gene, hybridization will not occur. Without hybridization, the radioactive probe