DNA as Genetic Material
Scientists discovered that DNA is the primary factor in defining the characteristics of most living organisms. However, some viruses use RNA instead. So, for something to be genetic material, it must:
- Be able to create clones of itself (self replicable).
- Be stable structurally and chemicaly.
- Allow for mutations, which can lead to evolution.
- Be able to pass on traits according to Mendel’s inheritance principles.
Most other compounds, such as proteins, carbohydrates, and lipids, did not meet the previously listed criteria. While RNA could meet those requirements, DNA was favoured over RNA for genetic material for a number of reasons:
- DNA has more structural stability than RNA.
- DNA has higher chemical stability than RNA.
- DNA has a double-stranded structure that allows it to effectively repair replication faults.
- RNA is required for protein production because DNA cannot directly code for them.
Approximate content of DNA in few organisms is given below:
|
Species |
DNA amount pg/per cell |
No. of nucleotide pairs (in millions) |
|---|---|---|
|
Bacteriophage T4 |
0.0024 |
0.7 |
|
Bacteria |
0.002-0.06 |
2 |
|
0.02-0.17 |
20 |
|
|
Sponges |
0.1 |
100 |
|
Molluscs |
1.2 |
1000 |
|
Crustaceans |
3 |
2800 |
|
Fishes |
2 |
2000 |
|
7 |
6500 |
|
|
Birds |
2 |
2000 |
|
Reptiles |
5 |
4500 |
|
6 |
5500 |
DNA as Genetic Material – Hershey And Chase Experiment
The Hershey and Chase Experiment, conducted in 1952 by Alfred Hershey and Martha Chase, demonstrated that DNA contains genetic information. They accomplished this by investigating viruses that infect bacteria, known as bacteriophages. In these tests, scientists labelled the virus’s DNA with a radioactive marker while labelling the protein coat independently with another marker.
When the viruses infected bacteria, researchers discovered that only the DNA identifier, not the protein marker, was passed along to the next generation of viruses. This helped to demonstrate that DNA, not protein, is the molecule that conveys genetic instructions. We will read about the Hershey and Chase Experiment in detail in this article.
Table of Content
- Hershey and Chase Experiment
- DNA as Genetic Material
- What is the Pulse and Chase Experiment?
- Conclusion -DNA as Genetic Material: Hershey And Chase Experiment
- FAQs on DNA As Genetic Material – Hershey And Chase Experiment