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8 Cards in this Set
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- 3rd side (hint)
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Risk assessment of someone who is autosomal dominant
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1. risk to offspring of affected is 50% regardless of whether affected is result of new mutation
2. risk to sibling of affected depends on whether affected is result of new mutation ex: 50% of those with NF is due to a new mutation |
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Define the following:
1. prior probability 2. conditional probability 3. joint probability 4. posterior probability |
1. prior probability: mendelian risk
2. conditional probability: the chance of an observed outcome given a particular genotype (either carrier or non-carrier) 3. joint probability: product of the prior and conditional probabilities (multiply prior and conditional probabilities) 4. posterior probability: one joint probability is weight against the other |
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What is Bayes analysis?
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mathematical method used to calculate recurrence risks
certain factors can be taken into account during the calculation of carrier risks these include likelihood of a new mutation, penetrance of a given gene, information from the pedigree, and test results |
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What is the risk assessment for autosomal recessive?
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-risk to offspring of affected depends on carrier status of spouse
-if spouse is a carrier, risk to offspring is 50% -if spouse non-carrier, risk to offspring is 0% -if spouse has condition, all offspring are carriers -risk to sibling of affected is 25% (for sibling to be affected) |
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What is hardy weinberg?
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-law that relates gene frequency to teh genotype frequency, used in population genetics to determine the allele frequency and heterozygote frequency when the incidence of a disorder is known
what are the 5 assumptions with this equation? |
1. randomly mating population
2. fairly large population 3. negligible amount of mutation 4. negligible amount of migration into and out of population 5. negligible amount of selection, with all genotypes equally viable and fertile |
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What are the equations used in hardy weinberg?
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For 2 alleles of an autosomal gene, B and b, the genotype frequenices in a population become, after one generation:
-freq of B/B=p^2 -freq of B/b=2pq -freq of b/b=q^2 p+q=1 p^2+2pq+q^2=1 these relative genotype frequencies will remain constant from generation to generation as long as the allele frequency remains constant (random mating, no migration, no selection) |
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What is the risk assessment for x-linked recessive?
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1. typically only males affected
2. affected males pass to all daughters who are carriers 3. 1/3 cases expected to be due to new mutation (not inherited from mother) **ONLY time we take this 1/3 into account is if there a SINGLE affected male in an x-linked recessive condition if there is more than 1 male, we would NOT use this bc the chances of both males being affected by a NEW mutation is VERY unlikely****** |
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How are the following inherited?
1. sickle cell 2. duchennes 3. CF 4. hemophilia |
1. sickle cell: autosomal recessive
2. duchennes: x-linked recessive 3. CF: autosomal recessive 4. hemophilia: x-linked recessive |
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