1. Tardigrade
  2. Question
  3. Biology
  4. In this type of questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as: Assertion: Drosophila flies can be subjected to a contact with pure CO 2 for long hours, without injury. Reason: CO 2 insensitivity is due to sigma factor.

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. In this type of questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
Assertion : Drosophila flies can be subjected to a contact with pure $CO _2$ for long hours, without injury.
Reason : $CO _2$ insensitivity is due to sigma factor.

Principles of Inheritance and Variation

Solution:

Normal strains of Drosophila do not show sensitivity towards pure $CO _2$. L, Heritier and Teisser $(1958)$, however, discovered a true breeding strain of Drosophila which was sensitive to $CO _2$. Sensitive mother always give sensitive progeny, sensitive fathers rarely give sensitive progeny if the mother is normal. This sensitivity can be attributed to a virus like particle called sigma found in cytoplasm of the cells of a sensitive fly. Sigma factor is transmitted through egg cytoplasm and its reproduction depends on initial supply and on suitable temperature of $20^{\circ} C$, because it is heat labile at high temperature.