Probability

Question 1

probability

Answer 1

number that reflects the chance or likelihood of event occurring

Question 2

independence

Answer 2

the occurrence of one does not affect the occurrence of another

Question 3

multiplication rule

Answer 3

probability of a given outcome in multiple trials is the given product of the probabilities of each trial outcome

probability of having three girls
1/2x1/2x1/2=1/8
same for boys

Question 4

addition rule

Answer 4

probability of either one outcome or another in the sum of two probabilities
probability of producing either three girls or three boys
1/8+1/8=1/4

Question 5

gene/genotype frequency specifies

Answer 5

the proportion of each allele in a population

the proportion of each genotype in a population

Question 6

know how to calculate gene/geneotype frequency

Answer 6

WILL be on test, practice maths

Question 7

Hardy-Weinberg Principle

Answer 7

specifies the relationship between gene frequency and genotype frequenct

useful in estimating gene frequency from disease prevalence data (to estimate the incidence of heterozygous carriers of recessive disease gene)

Question 8

Equation

Answer 8

know it and how to use it, practice maths

Question 9

autosomal dominant inheritance patterns

Answer 9

vertical transmission

no skipped generations

equal number of affected males and females

father to son transmission may be observed

Question 10

autosomal recessive inheritance patterns

Answer 10

clustering of the disease among siblings

disease is not usually seen in parents or anscestors

equally affects males and females

consaguinuity may be present

Question 11

consangenous matings more likely to produce offspring affected with

Answer 11

rare autosomal disorders

mortalitiy rate is high in first cousin mating offspring

Question 12

A polygenic trait is one in which

Answer 12

variations are thought to be caused by the combined effects of multiple genes

Question 13

Multifactorial factors are

Answer 13

environmental factros that cause variation in a trait

additive effects of genetic and environmental factors, tend to follow a normal bell curve, shows quantitiatve traits

Question 14

Liability of distribution

Answer 14

for diseases that do not follow the bell-curve, ther is a distribution in an underlying liability distribution

Question 15

Threshold of Liability

Answer 15

for multifactorial disease that are either present or absent, it is thought that a threshold of liability must be crossed before the disease is expressed

below threshold: peron appears normal

above threshold: person is affected by disease

Question 16

Example of multifactorial inheritance

Answer 16

pyloric stenosis

five times more common in males than females

least affected sex has a higher risk threshold and transmits teh condition more often and to the most frequently affect sex

meaning: males need less genetic risk to show sx and women need more genetic risk to show sx

children born of women with pyloric stenosis are more likely to be bron with the condition (especially males)

children of affected males are less likely to be born with condition

Question 17

Recurrence risks for multifactorial diseases can change

Answer 17

gene frequencies and environmental factors can differ among populations

Question 18

recurrence risk is higher if

Answer 18

more than one family member is affected

Question 19

if expression of disease in the proband is more severe then the recurrence risk is

Answer 19

higher

Question 20

recurrence risk is higher if the proband is

Answer 20

of the less commonly affected sex

Question 21

the recurrence risk for the diseass usually decreases rapidly in

Answer 21

remotely related relatives

Question 22

Transmission patterns

Answer 22

simultaneous influence of multiple genetic and environmental factors

trait may be influenced by the combination of a single gene with large effects and a multifactorial background

additional genes and environmental factors might have individual effects