Question

Now a days it is possible to detect the mutated gene causing cancer by allowing radioactive probe to hybridise its complimentry DNA in a clone of cells,followed by its detection using autroradiography because:

• A. mutated gene does not appear on photographic film as the probe has complimentarity with it.
• B. mutated gene partially appears on a photographic with it.
• C. mutated gene compeletely and clearly appears on a photographic film.
• D. mutated gene does not appear on photographic film as the probe has no complimentarity with it.

Answer 1

The correct option is D mutated gene does not appear on photographic film as the probe has no complimentarity with it.

Cancer is characterised by the formation of tumors. When normal proto-onco genes get mutated they could form oncogenes that are capable of causing cancer. The presence of such mutated genes can be detected by hybridisation of its complementary DNA with a radioactive probe in a clone of cells. A probe is a single stranded DNA or RNA, tagged with a radioactive molecule. The hybridisation is followed by detection using autoradiography. Autoradiography is a technique that makes use of an X- ray film to visualize molecules that have been radioactively labeled. The probe will fail to bind to the mutated gene as it will not have complementarity and hence does not appear on the photographic film.