Genetics Flashcards
How would you describe the genetic component of a multifactorial disorder? What else plays a role in these disorders?
several genes each contribute some small amount to the quality of a trait
Environment
What’s an amorph or nullimorph
Total loss of function
Hypomorph?
Reduced function of a gene; usually recessive, depends on haplosufficiency.
If it is recessive it’s haplosufficient-meaning it takes mutations in both alleles to cause reduced function, because alone it’s sufficient to prevent disease.
Hypermorph
Increased function of a gene; usually dominant, depends on haplosufficency.
Antimorph
creates an antagonistic effect. Dominant negative mutation
Neomorph
creates a new effect or product. Gain of function mutation
Define epistasis
One gene is dependent on the presence of or more modifier genes.
What is the difference between a qualitative and quantitative trait?
Qualitative traits-yes or no (disease or normal)
Quantitative traits- measurable physiologic or biochem quantity.
Qualitative traits would usually be caused by
A) monogenic traits
B) polygenic traits
C) pleomorphic traits
D) kaopectate
A) A mutation in one gene creating different alleles one of which may cause a disease state.
If a disease demonstrates familial aggregation, what would be the best way to determine the degree of environmental influence?
Analyze twins for differences in phenotype based on their geneotype. Differences are likely environmental.
Remember that concordance is not proof of shared inheritance of a disease causing allele, nor is discordance proof that a disease is environmental
How do you measure familial aggregation?
How does a relative risk for heart disease of 50 compare to one of 3? Which is most likely the result of familial aggregation?
relative risk
The higher the relative risk the more likely its the result of familial aggregation.
This does not mean the disease is genetic, it could be environmental. It just means that the incidence in the family is higher than the general population. This could be due to aunt bettys spare ribs, leading to a spare tire on each member of the family.
Complete this comparison. For diseases with more of a genetic basis concordance should ______ as relatedness of affected family members _____.
Relatedness=more closely related
A) Increase decrease
B) Decrease decrease
C) Decrease increase
D) Increase increase
D
What is the purpose of genome wide association studies?
To examine many common genetic variants in different individuals to see if any variant is associated with a trait
Non affected and affected individuals compared and SNP determined. Differences in these are explored for potential genes of interest.
