MEP Flashcards
What is epidemiology?
→A resolved measure (diversity) of differences (variables)
What does molecular epidemiology determine?
→Disease distribution in time and place
→Disease transmission
→Disease manifestation
→Disease progression
How many targets do functional characteristics have?
→single
How many targets do genomic characteristics have?
→multiple
What are the types of diversities?
→Single Weighting
→Additive Weighting
What are single weighting diversity?
→Biochemical test
→Presence of O157 antigen
→Presence of Verotoxin
What are the different types of multiple weighting genomic factors?
→factoral- Presence or absence of a gene/base/s change
in genome/gene relative to location in the genome
→functional- Type of substitution (synonymous/non synonymous )
→temporal- Mutation rate (time since the last alteration)
What type of dendogram shows pattern relatedness?
→Spoligotyping
What does variable number tandem repeats result in?
→Result is a profile of the number of specific repeats at multiple genomic loci
Examples of corruptive mutations
→Deletions or Insertions (disrupting coding frame)
→Creation of STOP codons (truncation)
→Corruption of STOP codons (elongation)
→Corruption of CONTROL sequences (eg. promoters)
What is antigenic drift?
→the same antigen changing its sequence base by base
What does accurate predictions in molecular epidemiology assume?
→constant molecular clock
What does a high division rate result in?
→higher mutation rate
What are factors affecting molecular clock?
→Bacterial replication rate →proof reading fidelity →pressure from the host →Degree of redundancy in the genome →Transmission rate
Why is proof reading fidelity important to calculate molecular clock?
→Some species (eg HIV) have low fidelity promoting high mutation rate
→Gives idea on how much weighting is placed on a variant
Why is pressure from the host or environment important to calculate molecular clock?
→High selection pressure removes ‘weak’ mutants and emphasises clusters
→Loss of selection pressure allows deletions
Why is the degree of redundancy in the genome important for molecular clock?
→multiple copies of a single gene in the genome allow for mutations in one copy without compromising overall functionality
→Movement or recombination within genome may not effect phenotype
Which genes change the most?
→Hyper-variable genes
What genes are more likely to be associated with phenotype and virulence?
→conserved genes
What is antigenic shift?
→a sudden replacement of an antigen by recombination with another viral type that has evolved separately
What is molecular restriction typing?
→can monitor effectiveness of control measures
What does choosing the most appropriate system require?
→Knowing the most appropriate variable/s
→Quantitating variations and deriving diversity
→Generating identities or clusters
→Applying related data
