Genetic Material- DNA vs RNA

The search for the genetic material of the organisms began long back. Back in time, some debated protein is the hereditary material. But later, the experiments revealed that DNA is the genetic material which is responsible for the inheritance of traits. Hershey-Chase’s experiment proved it unambiguously. However, the hunt for the hereditary material continued and studies showed that RNA replaces DNA in some viruses like Tobacco, Mosaic virus, QB bacteriophage, etc., why? What are the properties of genetic materials? What is the difference between DNA and RNA? Let’s discuss the answers to these questions.

Genetic Material

Not every organism has DNA as their hereditary material, some have RNA. However, DNA is the predominant one. In the majority of higher level organisms, RNA plays the role of a messenger. Though both are nucleic acids, this difference in functions persist, why? Scientist elucidates that, this is due to the difference between the chemical structure of DNA and RNA. For a molecule to be considered as genetic material, it must accomplish certain properties. They are as follows:

  • Replication- it should be able to produce its copies.
  • It should have chemical and structural stability.
  • Mutation- it should offer a chance for evolution.
  • It should possess hereditary unit which expresses in the form of ”Mendelian Characters’’.

DNA vs RNA

The difference between DNA and RNA explains the reason why DNA serves as the genetic material instead of RNA. By comparing DNA and RNA, it is evident that both the nucleic acids are able to replicate. Stability is an important criterion which should not change with the physiological characteristics of an organism. DNA fulfills this criterion. This point was proved in Griffith’s experiment. The heat-killed S strain bacteria retained their virulent property when appropriate conditions were provided. In the case of RNA, 2-OH group present in them make them more reactive. Hence, DNA is proved to be less reactive chemically and more stable structurally than RNA. Another feature which makes DNA more stable than RNA is the thymine which is substituted by uracil in RNA.

DNA vs RNA_ Genetic material

The unstable nature of RNA makes it more labile to mutation. This property help virus with RNA as the genetic material evolves at a faster rate. At last, coming to the expression of Mendelian characters, RNA is much faster than DNA. That is RNA can independently code for protein synthesis while DNA is dependent on RNA for this. RNA acts as a messenger for DNA for protein synthesis.

Difference Between DNA and RNA

DNA

RNA

More stable

Less stable

Double-stranded structure

Single-stranded structure

Presence of deoxyribose sugar

Presence of ribose sugar

Thymine is present as a nitrogenous base

Uric acid is present instead of Thymine

Though both the nucleic acids can act as genetic material, DNA is much more preferred. DNA is stable both chemically and structurally which make it well-built genetic material. RNA in humans does not act as a genetic material but play various other roles such as an adapter, enzyme, helps in protein synthesis, etc. RNA functions as a messenger for information to be transferred.

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Practise This Question

Which of the following molecules acts as messenger of genetic information to make proteins?