Any hereditary information remains stored in the form of codes in the hereditary material. Hereditary materials are found in the chromosomes.
The substance which is responsible for the transfer of hereditary materials from one generation to other generation and expresses that information in the form of trait is called as hereditary material.
The bodies of organisms are formed by Bio chemicals. So, it is natural that hereditary material is also formed of these biochemicals.
Biochemicals are basically of two types- Proteins and Deoxyribose Nucleic Acid. The DNA has the capacity of replication. No other protein has the capacity of replication. Thus, it has been proved experimentally that DNA is the Genetic Material.
A. DNA is the basis of heredity
DNA is also considered as the basis for heredity. It has following reasons –
(i) It has capacity of duplication
(ii). It is found in every cell
(iii) The replica of DNA remains similar to DNA molecule
(iv) The replication of DNA completes before cell division
(v) If there is a change in the structure of DNA, it will cause symptoms of mutation or permanent changes.
B. Role of DNA
DNA has following roles to play in heredity –
(i) DNA is a hereditary material. All the hereditary information remains coded in the arrangement of nitrogenous bases of it.
(ii) DNA has the capacity of replication due to which it can form its replica which remains very similar to it. This action is necessary for passing the information in other cells and in the next generation also.
(iii) Crossing over results in the process of gene recombination.
(iv)The change in the sequence of DNA nucleotide or change in their number causes mutation which leads to variations.
(v) It produces RNA (Ribose Nucleic Acid) through transcription and RNA has important role in protein synthesis.
(vi) It controls the cell metabolism. For this, it takes help from RNA. Besides this it also controls the processes conducted by RNA and synthesis of bio-chemicals.