Genetic Mechanisms and Population Probabilities Flashcards
mutation that confers a novel property on the protein without necessarily altering its normal functions is
novel property
what is a disorder caused by novel property mutation?
Sickle Cell Disease
Why is sickle cell anemia a novel property mutation caused disease?
because hemoglobin containing the mutant B globin subunits are normal in their function of binding oxygen except in deoxygenated blood that they are less soluble and aggregate in sickle shape.
What is the Hardy-weinberg equation?
p^2 + 2pq + q^2
p+q=1
p^2 + 2pq + q^2=1
Assumptions in HWE:
- Population is ____
- ____ Mating
- Allele frequencies remain ____ over time
- No mutations
- No selection
- No migration
- large
- random
- constant
Genetic Drift (fluctuations in the frequency of alleles due to chance occuring in small populations) and founder or bottleneck effect (nonrandom distribution of alleles among founders of subpopulations) are effects of
small populations
Stratification, assortative mating(choice of mate; deaf community), and consanguinity are examples of
non-random mating
Mutation and migration are exceptions to
constant allele frequency
_____ of sickle cell trait have resistance to malaria and results in releatively increased fitness than either homozygote
carriers (heterozygote advantage)
mutation associated with a reduction or a complete loss of one or more of the normal functions of a protein is
Loss of function/gene dosage effects
what is a disorder caused by loss of function and gene dosage effects?
Thalassemias
alpha thalassemia distribution in the world is associated with
regions with prevalent malaria infection resistance to malaria
Most common form of alpha thalassemia are the result of deletions due to homologus pairing and unequal crossover between
between alpha 1 and alpha 2 genes
Hydrops fetalis or Hemoglobin Bart only occur in mutations that are in
Cis (aa/–)
Cis variant of alpha thalassemia minor is more prevalent in
southeast asia
Mutations that are missense, nonsense, and frameshift cause what type of thalassemia?
Beta thalassemia
200 pathogenic mutations in the HBB (beta globin) gene have been described, and this is an example of
Allelic heterogeneity
Mutations in gamma globin genes of fetal hemoglobin are usually
point mutations in the promoter region
*cause persistance HbF production into adulthood
Inappropriate expression of a gene at an abnormal time or place is
heterochronic or ectopic gene expression
What is an example of heterochronic/ectopic gene expression?
hereditary persistence of Hb F
What is an example of gain of function due to a point mutation increasing production of a normal protein?
Factor V Leiden
*Increase thrombosis (blood clot risk)
What is the molecular mechanism of a situation in which the total level of a gene product (a particular protein) produced by the cell is about half of the normal level and that is not sufficient to permit the cell to function normally?
Haploinsufficiency
*requires more than 50% of fully active gene to prevent disease
A mutation whose gene product adversely affects the normal, wild-type gene product within the same cell is
Dominant negative effect
