Mutations

Mutation may be defined as any change occurred in the DNA sequence, which changes the gene function regardless of the morphological or physiological results. It is permanent, hereditary and ruled by Mendel’s laws. Such chemical changes are constant and occur during the replication stage and they can be quickly fixed; however, a mutation may occur if not repaired. They can affect autosomal genes (dominant or recessive) or be linked to sex chromosomes. Mutation can result in several different types of change in sequences. This in genes can either have no effect, alter the product of a gene, or prevent the gene from functioning properly or completely. Mutations can also occur in non-genic regions. One study on genetic variations between different species of Drosophila suggests that, if a mutation changes a protein produced by a gene, the result is likely to be harmful, with an estimated 70 percent of amino acid polymorphisms that have damaging effects, and the remainder being either neutral or weakly beneficial. Due to the damaging effects that mutations can have on genes, organisms have mechanisms such as DNA repair to prevent or correct (revert the mutated sequence back to its original state) mutations. There are various types of mutation. Saying in it in a simple way, we know about four, which are: By origin, effect, levels at which they occur and the type of cell.
Mutation by origin: these are originated by different possible causes; chemical, physical or natural. There are two types of this mutation type: spontaneous and induced. The spontaneous changes in genetic material without any apparent reason and the induced is caused by external factor called mutagenic agents, like Hydroxylamine, Base analogs, oxidative agents, etc.
Mutation by effect: These are changes that directly harm the protein and this can be: sense mutation, which changes a codon and producers a modified protein that can work well or partially well; it can be non-sense:, which changes causes