Genetic mutation
A genetic mutation is a change in the DNA sequence of a gene. This results erroneous information in
making proteins. Thus,
proteins are absent, deficient or inadequate.
Causes genetic mutations
This change of the genetic
information may cause, during the
translation of the DNA, the production of a protein does not function properly. These
genetic mutations may be due
to both external and
internal factors:
- Internal factors generate
mutations called spontaneous mutations occurring during cell replication.
In general, they are rare and random, and therefore they are the main source of genetic diversity, engine of evolution. The causes of spontaneous mutations are unknown.
- Possible external factors are physical or chemical compounds; they can significantly increase the rate of mutations in certain circumstances. They are called mutagens, such as electromagnetic waves (X rays, gamma rays, ultraviolet rays), cigarettes, alcohol, or chemical substances like pesticides,
benzene derivatives, solvents, colchicine, (they cause an alteration in the number of chromosomes).
If a mutation affected the sex cells (called germ), it is
transmitted to the
descendants of the mutant individual. The new gene sequence is then called an allele. In some cases, this mutation may provide a selective advantage or otherwise be defective.
This is the basis of the process of evolution (this is the natural
selection).
However, for most accidental mutations (caused
by irradiation or chemicals), if it affects non-sex cells (called somatic), mutation is not transmitted and affects only the subject having suffered directly. If there is an uncontrolled overproduction of cells, there is the possibility of creating a tumor may develop into cancer. On the contrary, the effect without excessive division is negligible. So, in conclusion, some of these mutations can be harmful to the human body causing serious illnesses can be fatal.
