Question

Hello. Can someone tell me why is DNA the genetic material in most of the organisms & not RNA? I need answers with reasoning & explanation. Thanks!

Answer 1

DNA is more stable than RNA

Explanation:

one of the reason why DNA is the genetic material of the organism is because of the following reasons

1. DNA is a duplex which can store the information without any harm to the information which is being passed on. as the DNA gets replicated the information is stored in the exact way but when you want to amplify RNA it is really hard to do so. (Read a little on DNA replication)

2. DNA is stable in various environment because of the lack of free -OH (in the sugar backbone) in the deoxyribonucleotide backbone as compared to free -OH in ribonucleotide present in RNA.

3. (I am not sure of this reason, anybody is welcome to correct me) during duplex formation the DNA strands form H-bonds with each other making it much more invulnerable to the environmental effects of heat. also the charge on the DNA is a point to consider as it makes the DNA to be able to remain intact even in acidic condition and survive for long as it is natural for at least human cells to decrease the pH during high physical activities.

there are experiments which prove the same
1. Griffith experiment with Streptococcus pneumoniae on mouse
2. Avery experiment
3. Hershey-chase experiment

with evidences from the last two experiment it was made clear that DNA is the genetic material.

Note:
1. RNA also act as a genetic material as it is present in various viruses like TMV attacks plant, HIV attacks various animals, etc.
2. double stranded RNA also exists but during evolutionary scale these have now been incorporated as danger signal and are readily removed from cells.

Thank You!
You all are welcome to correct me and point out mistakes if done. they are not intentional