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Disruting Hardy Weinberg
Assortative mating:
Assortative mating is chosing a mate because they posess a certain what?
Assortative mating is usually _______, b/c people pick people who ____like ____.
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Trait
positive; look like themselves
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Distrubing Hardy weinberg
1. Asssortative mating: tendeency to pick partners with similar_____ ____, such as _____.
2. Why do expectations of HW not apply in these cases?
3. What is clinical example of autosomal dominant disorder? what do homozygotes have?
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1. medical problems, deafness
2. B/c genotype of mate at disease locus is not determined by allele frequencies from general population.
3. Achondroplasia; homozygotes have lethal dwarfism
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Disruptions to Hardy weinberg
Consanguinity and inbreeding:
1. consanguinity brings about ____ in frequency of ___ ____ disease by increasing frequency with which carriers of an ____ ______ disorder mate
2. consanguinous mating can cause very ____ disease because consanguinous mating allows uncommon _______ to become homozygous.
3. Example ?
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1. increase; autosomal recessive, autosomal recessive
2. rare; alleles
3. Ashkenazi Jews have mutant alleles for Tay-Sachs disease.
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Exceptions to constant allele Frequencies
Genetic Drift in small populations :
1. if the population is small, random effects such as increased fertility, occuring for reasons ______to carrying the _____ allele, may cause allele _____ to change from one generation to the next.
2. in a large population, what would happen with random effects?
3. Why is this different in a small population?
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1. unrelated; mutant; frequency
2. In a large population, random effects would average out.
3. In a small population, allele frequencies can fluctuate from generation to generation by chance.
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Mutation and Selection
1. Affect HW ____
2. what is fitness?
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1. slowly
2. chief factor that determines whether a mutation is lost immediately; the measure of the number of offspring of affected persons who survive to reproductive age
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Mutation and selection balance in X-linked recessive mutations :
1. Selection occurs in ____ males and not in ____ females.
2. B/c males have one X and females have 2, the pool of X-linked alleles in a population will be ____, with ____ of the mutant alleles appearing in males and ___ present in females.
3. As in autosomal dominant disease mutant alleles lost through selection must be replaced by what? why?
4.
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Hemizygous; heterozygous
2. partitioned; 1/3 in males, 2/3 in females
3. must be replaced by recurrent new mutations to maintain disease incidence.
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Ethnic Differences in Frequency of Genetic diseases
1. B-thalassemia - example of what?
2. what kind of genetic phenomena is it characterized by?
3. Common in people from where ?
4. Most common B-thalassemia _____ tend to cause ___% of disease in mediterranian, but don't appear in east asians.
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1. it's a disease of hemoglobin
2. example of ethnic differences in disease frequency and which alleles are responsible in populations where a high incidence of disease
3. Mediterranian or East Asian descent
4. Alleles; 90.
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Thing that fuck with Hardy weinberg
Genetic drift
1. FOUNDER EFFECT : when a small population does what?
2. why is small population different?
3. If one of the ____ _____ of a new group carries a rare allele, that allele will have a much higher frequency in new group.
4. example?
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1. When a small population breaks off from a larger one.
2. Because by chance, the smaller population may have randomly different alleles
3. original founders
4. High incidence of Huntington's disease in venezuela
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Founder effect
1. Old Order Amish - from where ? settled where?
2. What kinds of marriages?
3. What kind of genotype is Ellis-van Creveld Syndrome?
4. what are the symptoms?
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1. Old Order Amish migrated from Europe
2. large families and consanguineous marriages
3. autosomal recessive
4. short-limbed dwarfism, polydactlyly, abormal nails and teeth, heart defects
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