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Mutations

Although mutations sound negative, they are a fundamental part of natural evolution. Mutations allowed humans to evolve, and is also a large factor in making each human different.

 

Mutations create genetic diversity, but they can also be problematic. Some mutations are small, therefore making them not as life threatening, but others can cause great harm.

 

A mutation is technically defined as any changes or alterations in the sequence of nucleotides in DNA.

Point Mutations

 

One of the most common type of genetic mutations, point mutation, otherwise known as a base-pair substitution, alters a single nucleotide base pair.



There are three types of point mutations:



Silent Mutations: In a silent mutation, there is a change in the DNA sequence, but the mutation does not affects the produced proteins. There are multiple genetic codons (group of three) that codes for the same amino acid. If one of the three nucleotide is changed, depending on the location of the nucleotide, the same amino acid could still be produced.



Missense Mutation: In this mutation, the altered nucleotide sequence will create a different amino acid. Sometimes the change is little, and have no great effect on the individual, other times it could be very dangerous.



Nonsense Mutation: In a nucleotide sequence, there are always codons that signal the end of the translation process, which will stop the protein production. These codons are called "stop codons". In a nonsense mutation, the alteration of the nucleotide sequence will create a stop codon, instead of an amino acid. When this happen, the amino acid sequence is shortened considerably, resulting in a most likely nonfunctioning protein.

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Base-pair Insertions/Deletions

 

In an insertion/deletion, a nucleotide base pair is inserted or deleted from the original gene sequence, creating a frame shift that can affect the entire amino acid sequence, causing them to be nonfunctional.



 

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