10.11.18 Probabilities in Populations

Question 1

What are the molecular mechanisms of hemoglobinpathies?

Answer 1

1. Novel property mutations
2. Loss of function
3. Heterochronic or ectopic expression

Question 2

Mutation that confers a novel property on the protein without necessarily altering its normal functions (Sickle Cell Disease)

Answer 2

Novel property mechanism

Question 3

How is SCD genetically passed on?

Answer 3

Autosomal recessive

Question 4

Study of the distribution of alleles in populations and of how the frequency of alleles and genotypes are maintained or changed

Answer 4

Population genetics

Question 5

What is the Hardy-Weinberg Principle (2 equations)?

Answer 5

p+q=1

p^2 + 2pq + q^2 =1

Question 6

What is the Hardy-Weinbergy approximation for carrier frequency?

Answer 6

The carrier frequency is about twice the minor allele frequency which twice the square root of prevalence

2pq= 2q

Question 7

What are the assumptions in Hardy Weinberg Equilibrium?

Answer 7

1. Large population
2. Random mating
3. Constant allele frequency

Question 8

Fluctuations in the frequency of alleles resulting from chance occurrences operating in small populations

Answer 8

Genetic drift

Question 9

Non-random distribution of alleles among the individuals who founded particular subpopulations

Answer 9

Founder (bottleneck) effect

Question 10

What are some examples of non-random mating?

Answer 10

1. Stratification
2. Assortative mating
3. Consanguinity

Question 11

Population that contains a number of subgroups that have remained genetically separate during modern times (AA and White mating)

Answer 11

Stratification

Question 12

Choice of mate because the mate possesses some particular trait (deaf x deaf)

Answer 12

Assortive mating

Question 13

Mating with someone who is related by descent

Answer 13

Consanguinity

Question 14

What are some exceptions to constant allele frequency?

Answer 14

1. Selection against or for alleles
2. Mutation
3. Migration

Question 15

Measure of the number of offspring or affected persons who survive to reproductive age

Minor allele causing death; heterozygote advantage

Answer 15

Fitness

Question 16

introduction of new alleles in a population

Answer 16

Mutation

Question 17

Mutations associated with a reduction or a complete loss of one or more of the normal function of a protein (Thalassemia)

Answer 17

Loss of function

Question 18

More than 200 pathogenic mutations in the HBB gene have been described. This is an example of what?

Answer 18

Allelic heterogeneity

Question 19

Inappropriate expression of a gene at an abnormal time or place (Hereditary persistence of fetal Hb)

Answer 19

Heterochronic or ectopic gene expression

Question 20

What molecular mechanism does Factor V Leiden illustrate?

Answer 20

Gain of function- mutant protein enhanced in normal properties and increases production of normal protein (enhanced thrombin generation – venous thrombosis; persists longer in circulation)

Question 21

Loss of half of the normal activity of a protein; refers to dominant phenotypes

Answer 21

Haploinsufficiency

Question 22

Abnormal protein causes an abnormal phenotype by interfering with function of the product of the normal allele (osteogenesis imperfecta)

Answer 22

Dominant negative effect

Question 23

Number of different mutant alleles at a single locus

Answer 23

Allelic heterogeneity

Question 24

Phenotype can be produced by mutations at two or more different loci

Answer 24

Locus heterogeneity

Question 25

At least two cell lines are present that differ in genotype or karyotype

Answer 25

Mosaicism

Question 26

Probability that a gene will have any phenotypic expression

Answer 26

Penetrance

Question 27

One gene has multiple phenotypic effects, particularly when the effects are not obviously related

Answer 27

Pleiotropy

Question 28

Severity of expression of the phenotype, although there is always some degree of expression present

Answer 28

Variable expressivity

Question 29

How is Factor V Leiden inherited?

How are thalassemias, SCD inherited?

How are blood groups inherited?

Answer 29

Autosomal dominant

Autosomal recessive

Codominant