Question

Which sequence of steps is correct in the development of a genetically modified (GM) crop?
A. Insertion of the gene into the vector.
B. Identification of a desired gene.
C. Selection and screening of transformed plants.
D. Transfer of the vector into a plant cell.
Choose the correct answer from the options given below:

• A. A, B, C, D
• B. B, A, D, C
• C. A, C, B, D
• D. D, A, C, B

Hint:

Think of the process like sending a letter. First, you decide what to write (\textbf{B}, identify gene). Then, you put the letter in an envelope (\textbf{A}, insert into vector). Next, you mail the envelope (\textbf{D}, transfer vector). Finally, you check if the recipient received and understood it (\textbf{C}, select and screen).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The question asks for the logical and chronological sequence of steps required to create a genetically modified (GM) plant.
Step 2: Detailed Explanation:
Let's arrange the steps in a logical workflow:

B. Identification of a desired gene: The very first step is to identify a gene that confers a desirable trait (e.g., insect resistance, herbicide tolerance, improved nutrition). You must know what gene you want to transfer before you can do anything else.
A. Insertion of the gene into the vector: Once the desired gene is isolated, it needs to be inserted into a suitable carrier, or vector (usually a plasmid like the Ti plasmid from {Agrobacterium tumefaciens}). This creates a recombinant DNA molecule.
D. Transfer of the vector into a plant cell: The recombinant vector is then used to transfer the desired gene into the target plant cells. This can be done using methods like {Agrobacterium}-mediated transformation or a gene gun.
C. Selection and screening of transformed plants: The transformation process is not 100\% efficient. Therefore, after transformation, it is crucial to select the cells that have successfully incorporated the new gene (often using selectable markers like antibiotic resistance) and then regenerate whole plants from these transformed cells. These plants must then be screened to confirm the presence and expression of the new gene and the desired trait.
Step 3: Final Answer:
The correct sequence of steps is: Identify the gene (B), put it in a vector (A), transfer the vector to the plant (D), and then select and screen the results (C). This corresponds to the order B, A, D, C.