Multifactorial Inheritance Flashcards
4 characteristics of complex traits?
1) aggregate in families 2) do not follow simple Mendelian inheritance 3) due to variants in multiple genes and non-genetic factors 4) no simple relationships in the population
A ____ heritability implies that differences among individuals with respect to a trait in a population can be attributed to differences in the genetic make-up.
high
_____ is indicated when there is an increased risk to relatives, but there is no consistent pattern of inheritance within families.
Multifactorial inheritance
Give an example of incomplete penetrance.
Type I diabetes and MHC
Multifactorial inheritance
When there is an increased risk to relatives, but there is no consistent pattern of inheritance within families.
Give an example of an allele-linked heterogeneity disease.
cystic fibrosis
Give an example of a variation due to the presence of phenocopies.
Thalidomide-induced limb malformation vs. genetically-induced
Presence of phenocopies
Individuals who have the disease or trait for reasons that are not primarily genetic even though clinical presentation mimics the more genetic version
Who are studied to try to determine genetic vs. environmental causes of variation in traits?
twins (monozygotic vs dizygotic)
The _______ of a trait is the proportion of total variance in a trait that is due to variation in genes.
heritability
Incomplete penetrance
not everyone with predisposing variant develops disease
A low heritability does not imply that _____ is not important.
environment
A high heritability does not imply that _____ are not important.
non-genetic factors
Give an example of a locus-linked heterogeneity disease.
Alzheimer’s Disease
The heritability of a trait is the proportion of total variance in a ____ that is due to variation in ____.
trait; genes
