1-17 Bayesian calculations Flashcards
heritability
measurement of the degree to which a characteristic is inherited
“Often expressed as h2, it is the proportion of the phenotypic variance caused by additive genetic variance. It is calculated using normal distribution statistics, can be estimated by studying concordance rates in mono- and dizygotic twins, and is reflected by the degree of resemblance between relatives.”
laws of multiplication and addition
probability of two independent events occuring is equal to the PRODUCT of their individual probabilities.
the probability of EITHER one of two mutually exclusive events occuring is equal to the SUM of their probabilities
bayesian risk calculation
General probability theorem used to calculate the relative probability of two alternate possibilities. Columns are set up for both possibilities, and prior, conditional, joint (prior * conditional), and posterior (joint/(joint + alt joint)) values are assigned for each.
thresholds
model to explain expression of characteristics. If someone has enough of a certain allele to express the characteristic, then they have surpassed the threshold amount.
combined with distribution graph can show what proportion of population should express the trait
normal distribution
can be used to calculate the heritability correlation coefficient
continuous variation
shown by quantitative traits
multifactorial inheritance
refers to traits determined by several genetic/environmental factors (71 loci of crohns’)
quantitative inheritance
deals with traits that are not inherited in a simple mendelian fashion nor associated with chromosomal abnormalities.
-genetic factors play an important role in their causation (weight, height)
multifactorial inheritance in familiies is noted by
clustering without an obvious pattern
recurrance risk increased with more
affected family members and increasing maltormation severity.
