KA4 Mutations Higher Human Biology

Mutation

A random change in the DNA which results in no protein or an altered protein being synthesised.

Single Gene Mutation

Changes to a DNA nucleotide sequence which alters the sequence of bases on the DNA.

Substitution Mutation

Replacement of one nucleotide by another, causing missense, nonsense, or splice-site effects.

Missense Mutation

A substitution that changes a single amino acid in the protein.

Nonsense Mutation

A substitution that results in a premature stop codon, producing a shortened protein.

Splice-Site Mutation

A mutation resulting in some introns being retained and/or some exons not being included in the mature transcript.

Frameshift Mutation

A mutation caused by nucleotide insertions or deletions.

Insertion (Single Gene)

Addition of one or more nucleotides to the DNA sequence, causing a frameshift.

Deletion (Single Gene)

Removal of one or more nucleotides from the DNA sequence, causing a frameshift.

Chromosome Structure Mutations

Mutations that alter the structure of a chromosome, affecting multiple genes.

Types of Chromosome Mutations

Duplication, deletion, inversion, and translocation.

Chromosome Duplication

When a section of a chromosome is added from its homologous partner.

Chromosome Deletion

When a section of a chromosome is removed.

Chromosome Inversion

When a section of a chromosome is reversed.

Chromosome Translocation

When a section of a chromosome is added to another chromosome, not its homologous partner.

What do Frameshift Mutations cause?

All codons and amino acids after the mutation to be changed

Effects if Chromosome mutation

Lethal

Example of condition caused by Deletion

Cri-du-chat Syndrome

Example of condition caused by Duplication

Cancers

Example of condition caused by Inversion

Haemophilia A

Example of condition caused by Translocation

Lymphoma