Mutations can be caused by errors during the DNA repairing process or errors during the replication process. They can also be induced. Induced mutations are caused by chemicals, radiation, diseases and genetic manipulation.
Approximately one out of 100,000,000 copies of DNA strands incurs an error. This produces a naturally occurring mutation. It is estimated that each individual carries up to 10 latent deadly mutations, according to the Tech Museum of Innovation. Cancer is also a form of cell mutation in which the lack of gene p53 leads to the division of mutated cells that become tumors.
Environmental mutations are caused by chemicals that damage the DNA, and they include ultraviolet radiation, tobacco and nitrous acid. Mutations can occur by the deletion, duplication, inversion, insertion or translocation of genes on a chromosome.
Mutations can be beneficial, harmful or neutral to the organism. Harmful mutations include hereditary diseases and errors occurring in the DNA repairing process. Beneficial mutations can cause resistance to HIV and malaria. There are recessive genetic diseases that need two gene copies to cause the illness, but for which only one copy of the mutant gene can cause beneficial effects; for example, having just one copy of the sickle-cell mutated gene helps protect against malaria. Dominant genetic diseases need only one copy to cause harm, such as in the case of Huntington`s disease.