Which of the following is NOT a basic step in the genetic modification of an organism?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Identification of DNA with maximum number of genes
NCERT lists three basic steps in genetically modifying an organism: identifying DNA with desirable genes, introducing it into the host, and maintaining it in the host and passing it to the progeny.
Option (1) Introduction of the identified DNA into the host — A basic step. NCERT gives introduction of the identified DNA into the host as step (ii). The DNA chosen must be put into the host cell before it can act there.
Option (2) Identification of DNA with maximum number of genes — Not a basic step. What matters is the desirable gene, not the largest number of genes.
Option (3) Maintenance of introduced DNA in the host — A basic step. Step (iii) in NCERT is maintenance of introduced DNA in the host. The DNA must stay and work in the host cell; otherwise the change is lost.
Option (4) Transfer of the introduced DNA into the progeny of host — A basic step. Step (iii) also includes transfer of the DNA to its progeny. Passing the DNA to the next generation keeps the new trait in the line.
NCERT Extract:
Principles of Biotechnology – “… You can hence infer that there are three basic steps in genetically modifying an organism —
(i) identification of DNA with desirable genes;
(ii) introduction of the identified DNA into the host;
(iii) maintenance of introduced DNA in the host and transfer of the DNA to its progeny.”