mutations

Substitutions

• When a base pair is inserted instead of another (it’s substituted)

• By cause mutations 

Indels 

• when a base pair is inserted or deleted 

• By cause

Silent mutations

• if a mutation occurred and it does not affect the end protein product

• By effect 

Missense mutation 

• The mutation causes the codon to code for a different amino acid and is prevalent in the final protein product.

• By effect 

Nonsense mutation

• when the mutation changes a codon to become a stop codon

• By effect

Frame shift mutation

• when an indel moves the codon reading frame, and codons are now read in the wrong sequences, resulting in a completely wrong protein

• by effect

Silent mutations are caused by…

Substitutions: yes if the base added codes for the same amino acid.

Indels: yes if they are added/ deleted in 3’s and do not affect the protein’s structure.

Missense mutations are caused by…

Substitutions: Yes, if the bases added make a different amino acid.

Indels: Yes, if the bases are in multiples of 3 and make an amino acid that affects protein structure

Nonsense mutations are caused by…

Substitution: Yes, if the base substituted now codes for a stop codon

Indels: yes, if the bases are inserted/deleted, alter the frame so that a stop codon occurs where the insertion occurs, or if three bases are inserted, create a stop codon.  

Frame shift mutation are caused by

substitution: no

Indels: yes, when bases that aren’t in a multiple of three are added and make all the codons be read in the wrong sequence

Mutations

Permanent changes in DNA that lead to new alleles

Mutations in promoter region

causes loss or change of gene expression

Mutation in exons (coding regions)

Effect how a protein is produced

Mutations in introns

can affect how genes/protein products are spliced, effecting final protein product

Alleles vs Genes

Alleles are different versions of a gene

All human have the same genes, but different alleles that change how to protein is made

(same protein but different version)

Mutations and genetic diversity

Mutation are the basis of genetic diversity, as they add new alleles and thus phenotype into a population, leading to evolution.