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Inversion of Genes

This is where the order of a particular order of genes are reversed as seen below
Normal chromosome un-altered
The connection between genes break and the sequence of these genes are reversed
The new sequence may not be viable to produce an organism, depending on which genes are reversed. Advantageous characteristics from this mutation are also possible.

Translocation of Genes

This is where information from one of two homologous chromosomes breaks and binds to the other. Usually this sort of mutation is lethal
An un-altered pair of homologous chromosomes
Translocation of genes has resulted in some genes from one of the chromosomes attaching to the opposing chromosome.

Alteration of a DNA Sequence

The previous examples of mutation have investigated changes at the chromosome level. The sequence of nucleotides on a DNA sequence are also susceptible to mutation.
DeletionHere, certain nucleotides are deleted, which affects the coding of proteins that use this DNA sequence. If for example, a gene coded for alanine, with a genetic sequence of C-G-G, and the cytosine nucleotide was deleted, then the alanine amino acid would not be able to be created, and any other amino acids that are supposed to be coded from this DNA sequence will also be unable to be produced because each successive nucleotide after the deleted nucleotide will be out of place.

Insertion

Similar to the effects of deletion, where a nucleotide is inserted into a genetic sequence and therefore alters the chain thereafter. This alteration of a nucleotide sequence is known as frameshift.

Inversion

Where a particular nucleotide sequence is reversed, and is not as serious as the above mutations. This is because the nucleotides that have been reversed in order only affect a small portion of the sequence at large.

Substitution

A certain nucleotide is replaced with another, which will affect any amino acid to be synthesised from this sequence due to this change. If the gene is essential, i.e. for the coding of haemoglobin then the effects are serious, and organisms in this instance suffer from a condition called sickle cell anaemia.
All of the genetic mutations looked at through the last 2 pages more or less have a negative impact and are undesired, however, in some cases they can prove advantageous.

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Genetic mutations increase genetic diversity and therefore have an important part to play. They are also the reason many people inherit diseases.
The next page looks at polyploidy, a type of mutation that effects chromosome content of an organism, and also investigates the frequency of mutations and factors that play a part in this.

Deletion of a Gene

As the name implies, genes of a chromosome are permanently lost as they become unattached to the centromere and are lost forever
Normal chromosome before mutation
Genes not attached to centromere become loose and lost forever
New chromosome lacks certain genes which may prove fatal depending on how important these genes are.

Duplication of Genes

In this mutation, the mutants genes are displayed twice on the same chromosome due to duplication of these genes. This can prove to be an advantageous mutation as no genetic information is lost or altered and new genes are gained.

Normal chromosome before mutation

Genes from the homologous chromosome are copied and inserted into the genetic sequence
New chromosome possesses all its initial genes plus a duplicated one, which is usually harmless
The next page continues looking at these chromosome mutations and mutations that happen within genes that can prove to be more harmful to the organism at hand. The following pages also investigates polyploidy in species.

By: Naofer (",)