Mutation and Mutagenesis Mutation is a sudden heritable

Mutation and Mutagenesis Mutation is a sudden heritable change in the genetic material of an organism.

Types of mutations 1 - Spontaneous mutations ( normal ) • a- Somatic mutations • b-Germinal mutations • 1 - Chromosomal mutations ( result of aberrations ) 2 - Gene mutations • # Macromutations ( major gene ) • # Micromutations ( minor gene ) • # Molecular or point mutation • • 2 - Induced mutations ( by human ) • 3 - Cytoplasmic mutations ( Classed as plasmon and • plastidom ) 4 - Conditional mutations (related to environment ) • a- If show phenotypic expression ( restrictive conditions ) • b- if do not show phenotypic expression ( permissive conditions ) •

Classes of conditional mutations 1 - Auxotrophic ( restrictive condition ) • 2 - Temprature-senstive – ( can grow under high and low temprature) – 3 - Suppressor-sensetive (need another genetic • factor called suppresor )

Mutagenic agents 1 - Physical mutagens • a- High-energy ionizing radiations ( x-rays , • gamma , beta and alpha particles , neutrons ) b- Low-energy non-ionizing ( ultraviolet • light) 2 - Chemical mutagens •

Chemical mutagens 1 - Base analogues and related compounds • ( similar to one of the four DNA bases in • which can be incorporated into a DNA molecule during replication ) 2 - Antibiotics ( chromosome breaking ) • 3 - Alkylating agents ( alkyl group ) • 4 - Azide ( carcinogenic ) •