Mutation
![](https://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/DNA_replication_en.svg/280px-DNA_replication_en.svg.png)
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Inbiology,amutationis a change in thegeneticmaterial.This means changes to theDNAor to thechromosomeswhich carry the DNA. These changes areheritable(can be passed on to the next generation) unless they havelethaleffects.
Mutations can happen for several reasons. It can happen because oferrorswhenmeiosisproduces thegametes(eggs&sperms).Damagebyradiation,or by certainchemicalsmay cause mutations. Mutations occur atrandom.
Also, by derivation, an individual carrying the mutation may be called amutantor amutation.So is thetrait(character) most obviously affected by the mutation.[1]
Types of mutation
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DNA mutations
[change|change source]When DNA is copied mistakes are sometimes made – these are called mutations. There are four main types of mutations:
- Deletion,where one or more DNA bases are left out.
- Insertion,where one or more extra base is put in.
- Substitution,where one or more bases are changed for another base in the sequence.
- Duplication,where whole genes are copied.
Chromosome mutations
[change|change source]These terms are explained in the third diagram.
- Deletion:a piece of chromosome is lost, together with any genes which may be on it.
- Duplication:part of a chromosome is repeated
- Inversion:part of a chromosome is reversed end to end
- Insertion:a smaller chromosome is added into a longer chromosome
- Translocation:part of a chromosome gets moved onto another chromosome
Results of mutation
[change|change source]Mutations may be bad for the organism, or neutral, or benefit the organism. Sometimes mutations are fatal for the organism – theproteinmade by the 'new' DNA does not work at all, and causing theembryoto die. On the other hand,evolutionis moved forward by mutations, when the new version of the protein works better for the organism.
Mutations are the ultimate source ofvariation,upon whichnatural selectionacts. What happens is that some mutations affect the organism's ability to live and reproduce. This is an important part of thetheoryofevolution.The amount of heritable variation carried by a population can be huge, and as a result natural populations can change andadaptto conditions in theirenvironment.[1]
References
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