Mutations

Mutation

A permanent alteration in the primary DNA sequence, which may result in changes in the functioning and folding of the resulting protein

How do mutations occur

Mutations can occur from normal cellular divisions, or exposure to mutants such and chemicals, radiation and ultraviolet light

Point mutations

Changes to one singular nucleotide in a gene

Silent mutation

A point, substitution mutation which occurs when one nucleotide is substituted for another nucleotide however does not effect the resulting codon and therefore polypeptide (degenerate and redundant)

Missense mutations

A point, substitution mutation where one nucleotide is substituted for another nucleotide, resulting in the corresponding codon and therefore different amino acid, resulting in a changed primary structure and possibly effecting the function of the protein

Nonsense mutation

A point, substitution mutation where one nucleotide is substituted for another nucleotide, resulting in the corresponding codon resulting in a stop codon, terminating the transcription, resulting in a polypeptide change too short to function properly

Block mutations

Involve altering the structure of chromosomes by inserting, deleting, duplicating or swapping a cluster of nucleotides, potentially involving multiple genes

Types of block mutations

Deletion- a section of DNA is removed from a chromosome, shortening DNA

Duplication- a section of DNA is replicated on a chromosome, lengthening DNA

Inversion- a section of DNA has its sequence reversed on a chromosome

Translocation- a section of DNA is transferred to a different chromosome or switches places on a chromosome

Aneuploidy

A condition that describes the absence of a chromosome or the presence of an additional chromosome (single copy monosomy three copy trisomy)

Polyploidy

Condition where an individual has more than two sets of chromosomes (fatal)