Which of the following is a property of genetic material?

The correct answer is Option (1) → It should be stable enough to not change during different stages of the life cycle.

A molecule can act as genetic material only if it meets four needs: it can make copies of itself (replication), it is stable chemically and structurally, it allows slow changes (mutation) needed for evolution, and it can express itself as Mendelian characters. Stability means the genetic material does not change with the stages of the life cycle, with age or with changes in the physiology of the organism.

Option (1) It should be stable enough to not change during different stages of the life cycle. — Correct. This is the property of stability. The same genetic material must be carried unchanged through the whole life of the organism.

Option (2) It must degrade easily when exposed to heat. — Incorrect. Genetic material should not break down easily. In Griffith's experiment, heat killed the bacteria but did not destroy some properties of the genetic material. DNA strands separated by heat can come together again.

Option (3) It should mutate rapidly in response to environmental changes. — Incorrect. Genetic material should allow only slow changes (mutation) over time. Rapid change would make it unstable and the offspring would not resemble the parents.

Option (4) It must be structurally unstable to allow rapid adaptation. — Incorrect. Being structurally unstable goes against the need for stability. Evolution needs slow mutation, not an unstable molecule.

NCERT Extract:
Properties of Genetic Material (DNA versus RNA) – “… A molecule that can act as a genetic material must fulfill the following criteria: (i) It should be able to generate its replica (Replication). (ii) It should be stable chemically and structurally. (iii) It should provide the scope for slow changes (mutation) that are required for evolution. (iv) It should be able to express itself in the form of ‘Mendelian Characters’. … The genetic material should be stable enough not to change with different stages of life cycle, age or with change in physiology of the organism.”