Week 1 Flashcards
What is FISH
Technique used to locate a dna sequence on a chromosome
Used to visualise and map genes
Can identify mutations
What is a germ line mutation
Inherited
What is an acquired mutation
A mutation acquired after conception
What are the two types of functional mutation
Favourable
Non-favourable
What is a silent mutation
A mutation with no change to amino acids
What is a missense mutation
A mutation that changes one amino acid
What is a nonsense mutation
Change in amino acid which changes a stop codon
What is a frame shift mutation
Disruption of the triplet code
Can be insertion or deletion
What is splicing
Affects a splice site
Leads to an intron being removed incorrectly
What happens if there is a mutation in a promoter
Affects rate of transcription
What happens if there is a mutation in a regulatory region or operator site
Gene regulation failure
What happens if there is a mutation in the untranslated regions of 5’ or 3’ end
Disrupts mRNA translation / stability
Mutation in transfer RNAs, micro RNAs, or long non coding RNAs
Leads to dysfunctional gene regulation
What factors determine the effect of a mutation
- the amino acid affected
- amino acid chemical similarity
- sequence position and structure
What is conservative replacement
Amino acids have similar properties
So rarely cause protein dysfunction
What is radical replacement
Amino acids have different properties
So there is a change in phenotype or pathogenicity is caused
What is a loss of function gene
Mutation that reduces or prevents gene expression
What is the effect of a loss of function mutation
Dysfunction or complete loss (null or amorphic)
Often recessive
What is a gain of function mutation
Mutation causing new or abnormal function
Often dominant
What are chromosome aberrations
Aneuploidies
Changes to chromosome number or structure
Structural chromosome aberrations
Translocation
Inversion
Insertion
Amplification
Duplication
Deletion
Numerical chromosome aberrations
Loss or gain of function mutations of a whole chromosome set
What is haploinsufficiency
Where one allele is inactivated by a mutation
So only one functional copy remains
What is the effect of haploinsufficiency
The remaining functional copy doesn’t have enough product to be ‘normal’
Causes an abnormal or decreased state
In some autosomal dominant disorders
What is a dominant negative mutation
Where the non- functional allele does the opposite function to the normal wild type
Can cause phenotypic change like cancer tumours
