Range of Mutations

Mutations : 1.  Morphological Level (Including Lethal Mutations)
Brief History
Range of Mutations
Stages of Which Mutations Occur
Types of Mutations
Spontaneous Vs Induced Mutations
Mutation Rates and Frequencies
Induced Mutations 
Detection of Mutations in Drosophila 
Detection of Mutations in Plants
Use of Microbial Systems to Assess Potency of Mutagens
Practical Applications of Mutations
Effect of Genotypes on Induction of Mutations (Mutator Gene and Paramutations)
Adaptive Mutations and Genotrophs
Although changes due to single gene mutations may involve sudden and large changes (like that of Ancon breed of sheep), they can also be so small that one may not be able to notice them. Therefore, earlier concept that, mutations could involve sudden and big changes only, was not correct. Mutations could also be observed which do not involve any change in morphology but only modify nutritional requirements as in case of Neurospora (Mutations : 2.  Biochemical Level (Biochemical and Microbial Genetics)). similarly, mutations could be observed in pathogens, as a result of which a pathogen could lose or acquire virulence against a particular host.