Mutation
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| + | In [[biology]], '''mutations''' are changes to the [[base pair]] sequence of [[genetic material]] (either [[DNA]] or [[RNA]]). Mutations can be caused by copying errors in the genetic material during [[cell division]] and by exposure to [[ultraviolet]] or [[ionizing radiation]], chemical [[mutagens]], or [[virus (biology)|viruses]], or can occur deliberately under cellular control during processes such as [[meiosis]] or [[hypermutation]]. In multicellular organisms, mutations can be subdivided into ''[[germline mutation]]s'', which can be passed on to descendants, and ''[[somatic mutation]]s''. The somatic mutations cannot be transmitted to descendants in animals. Plants sometimes can transmit somatic mutations to their descendants asexually or sexually (in case when flower buds develop in somatically mutated part of plant). A new mutation that was not inherited from either parent is called a ''de novo'' mutation. | ||
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| + | Mutations create variations in the [[gene pool]], and the less favorable (or ''deleterious'') mutations are removed from the gene pool by [[natural selection]], while more favorable (''beneficial'' or ''advantageous'') ones tend to accumulate, resulting in [[evolution]]ary change. For example, a butterfly may develop offspring with a new mutation caused say by ultraviolet light from the sun. In most cases, this mutation is not good, since obviously there was no 'purpose' for such change at the molecular level. However, sometimes a mutation may change the butterfly's color, making it harder for predators to see it; this is an advantage and the chances of this butterfly surviving and producing its own offspring are a little better, and over time the number of butterflies with this mutation may form a large percentage of the species. [[Neutral theory of molecular evolution|Neutral mutations]] are defined as mutations whose effects do not influence the [[Fitness (biology)|fitness]] of either the species or the individuals who make up the species. These can accumulate over time due to [[genetic drift]]. The overwhelming majority of mutations have no significant effect, since [[DNA repair]] is able to mend most changes before they become permanent mutations, and many organisms have mechanisms for eliminating otherwise permanently mutated somatic cells. | ||
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In biology, mutations are changes to the base pair sequence of genetic material (either DNA or RNA). Mutations can be caused by copying errors in the genetic material during cell division and by exposure to ultraviolet or ionizing radiation, chemical mutagens, or viruses, or can occur deliberately under cellular control during processes such as meiosis or hypermutation. In multicellular organisms, mutations can be subdivided into germline mutations, which can be passed on to descendants, and somatic mutations. The somatic mutations cannot be transmitted to descendants in animals. Plants sometimes can transmit somatic mutations to their descendants asexually or sexually (in case when flower buds develop in somatically mutated part of plant). A new mutation that was not inherited from either parent is called a de novo mutation.
Mutations create variations in the gene pool, and the less favorable (or deleterious) mutations are removed from the gene pool by natural selection, while more favorable (beneficial or advantageous) ones tend to accumulate, resulting in evolutionary change. For example, a butterfly may develop offspring with a new mutation caused say by ultraviolet light from the sun. In most cases, this mutation is not good, since obviously there was no 'purpose' for such change at the molecular level. However, sometimes a mutation may change the butterfly's color, making it harder for predators to see it; this is an advantage and the chances of this butterfly surviving and producing its own offspring are a little better, and over time the number of butterflies with this mutation may form a large percentage of the species. Neutral mutations are defined as mutations whose effects do not influence the fitness of either the species or the individuals who make up the species. These can accumulate over time due to genetic drift. The overwhelming majority of mutations have no significant effect, since DNA repair is able to mend most changes before they become permanent mutations, and many organisms have mechanisms for eliminating otherwise permanently mutated somatic cells.
