Complex disease & pharmacogenetics Flashcards
What is an allele?
An alternative form of the gene occupying the same locus
What is a locus?
Specific position on a chromosome, whereby a gene responsible for a particular trait is located.
What is codominance?
Two different alleles of a heterozygote are both expressed in the phenotype
What is sex-linkage?
Results when genes are located on the sex chromosomes, whereas autosomal linkage is the converse
What is polygenic inheritance?
A single feature is determined by more than one interacting genes
A particular feature can significantly be influenced by environmental factors during development
What is a chi-squared test?
A statistical test to evaluate whether the observed phenotypic ratios differ significantly from the theoretical frequencies.
What is gene mapping?
A technique used to locate the specific position of a gene occupies on a chromosome
What is a phenotype?
Description of the character manifested by a gene
What is a genotype?
The genetic constitution of an individual at a particular locus
How many blood group allelic forms exist?
3, IA, IB, and IO
What are the mendelian traits?
Phenotype is controlled by a single gene, inheritance abides Mendelian principles; homozygous (identical genes); double homozygous cross breed results in single expressed phenotype and genotype within the first filial generation
How are Mendelian diseases studied?
Analyzing genetic pedigrees
What are the complex traits?
Phenotype is controlled by multiple genes, in addition to environmental influences
How are complex diseases studied?
Studied by evaluating affected individuals within a sampled population
What are SNPs (Genetics)?
Single nucleotide polymorphisms
DNA sequence variations that occur when a single nucleotide is altered; a common form of variation within the human genome.
What is association analysis?
Stratified population-based on genotype groups; identify whether the genotype can distinguish pathology of the disease, conduct a statistical tests to calculate significant difference of results.
What are GWAS?
Genome-wide association studies is an observational study of a genome-wide set of genetic variations in different individuals and identifying any variant associated with a trait.
What does a genome-wide association study require to be effective?
Requires large sample size, and multiple testing
False positives may occur, thus conduct an agnostic search
How is a genome-wide association study conducted?
DNA samples collected from healthy individuals, and those with expressed phenotypic disease traits
DNA and sequences & genotypes are identified, the population is stratified into respective genotype groups.
What is a risk allele?
The allele that is associated with the genetic predisposition of the disease; the allele that is evidently most frequency within the population and thus attributed to developing pathogenesis
What is an additive model?
The addition of each risk allele will increase the risk of disease to an extent.
What are the risk conditions for CVD?
Type 2 diabetes, obesity, high cholesterol, and high blood pressure
What are modifiable risk factors?
Risk factors are conditions that increase the risk of developing a disease. Modifiable factors are concerned with precautionary measures that can be undertaken to change and reduce the risk associated with the factors
What are some examples of modifiable risk factors?
Diet, sedentary lifestyle, smoking, and exercise
What is a risk factor analysis?
Regarding the study of complex disease, identifying modifiable risk factors are pertinent in establishing preventative public health measures and schemes aimed at targeting high-risk groups and lowering the potential for pathology.
Altering habits
Identifying genetic factors can be used to model and predict diseases - strategies can be implemented to facilitate individual lifestyle
Lifestyle habits are observed and collecting within the population, and correlated with risk & frequency of developing CVD.
What is heritability?
The level of phenotypic variations attributed to genetic factors
How can traits be established through twin studies?
Monozygotic twins have a 100% shared genetic component
Dizygotic twins have 50% shared genetic component
Twins have shared environmental conditions, therefore phenotypic variations can be compared to establish a relationship with the hereditary trait
Significant differences compared with monozygotic twins
What is missing heritability?
Single genetic variations cannot account for much of the heritability of diseases, and phenotypes
What are the explanations for missing heritability?
Rare single nucleotide polymorphisms (Risk alleles infrequent)
Low-frequency variants with intermediate effect; inability to be recognized during GWAs, gene interactions (not investigated); miscalculated estimation of heritability diagnosis; reproducibility of results
What is the definition of pharmacogenetics?
The study of variability in drug responses, due to genetic differences concerned with drug reactions, understanding the principles of pharmacogenetics on a patient individual basis can be used to improve drug therapy and prescription
How does genetics influence pharmacology?
Specific medications can be prescribed for the same condition to different patients, patients express degrees of variability in terms of inadvertent drug effects; the concept of personalized medicine
