Spontaneous and Induced mutations: 
Major differences
| 
Spontaneous
  mutations | 
Induced
  mutations | 
| 
1.     
  It is caused by
  natural agents, so it is also known as natural mutations or background
  mutations. | 
It is caused by man | 
| 
2.     
  Frequency of
  mutation is very low (about one per million genes) | 
It is very faster | 
| 
3.     
  It is due to  mutagens in many cellular products such as
  formaldehyde, nitrous acid, peroxides etc | 
It is due to physical
  mutagens (radiations, temperature etc) and chemical mutagens (mustard gas,
  vinyl chloride, acridine dyes, ammonia etc) |