Mutation

Mutation Dr. Mohammad Sabri
It is a heritable change in the genetic material (DNA).

Importance
1) They may have deleterious or (rarely) advantageous consequences to an organism.
2) They are important to geneticists: the most common way we study something is to break it.
3) Mutations are important as the major source of genetic variation which fuels evolutionary changes.

Causes of mutation
Mutations either spontaneous (molecular decay) or induced mutation (caused by mutagens).

Causes of spontaneous mutation
1.Tautomerism: A base is changed by the repositioning of a hydrogen atom, altering the hydrogen bonding pattern of that base resulting in incorrect base pairing during replication.
2. Depurination: Loss of a purine base (A or G) to form an apurinic site (AP site).
3. Deamination: Hydrolysis changes of a normal base to an atypical base containing a keto group in place of the original amine group. Such as, A ?hypoxanthine, which can be corrected by DNA repair mechanisms; and 5-methylcytosine