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In molecular biology and genetics, mutations are accidental changes in a genomic sequence of DNA: the DNA sequence of a cell's genome or the DNA or RNA sequence in some viruses. These random sequences can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic chemicals, as well as errors that occur during meiosis or DNA replication. They can also be induced by the organism itself, by cellular processes such as hypermutation.
Mutation can result in several different types of change in sequences; these can either have no effect, alter the product of a gene, or prevent the gene from functioning properly or completely. 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 having 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 mutations.
Other articles related to "mutation, mutations":
... Mapping between common terms from cancer biology and evolutionary biology Driver mutation = a mutation that gives a selective advantage to a clone in its microenvironment, through ... Driver mutations tend to cause clonal expansions ... Passenger mutation = a mutation that has no effect on the fitness of a clone but may be associated with a clonal expansion because it occurs in the same genome with a driver ...
... a parent, and also not passed to offspring, is called a somatic cell genetic mutation or acquired mutation ... Cells with heterozygous mutations (one good copy of gene and one mutated copy) may function normally with the unmutated copy until the good copy has been spontaneously somatically mutated ... This kind of mutation happens all the time in living organisms, but it is difficult to measure the rate ...
... The mixed mutation causes The soft mutation of b /b/ → v /v/, g /ɡ/ → c'h /x/, gw /ɡw/ → w /w/, m /m/ → v /v/ Hard mutation of d /d/ → t /t/ ...
... The Clearwing budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars ... It is the underlying mutation of the Clearwing variety, often known as Yellowwings in the green series and Whitewings in the blue series ... When combined with the Greywing mutation the variety is known as the Full-bodied Greywing ...
... The Clearwing mutation is one of the few that affect different areas of the body selectively ... Like many budgerigar mutations, it is the black melanin pigment that is affected ... The Clearwing mutation causes a large reduction in the number of pigment granules in the cortex, but only a very small reduction in the number of pigment granules ...