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12 Cards in this Set
- Front
- Back
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What are the assumptions of Hardy Weinberg?
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Random mating
No selection No new mutations Population is infinitely large No migration |
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Hardy Weinberg equation
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p^2 + 2pq + q^2 = 1
when p + q = 1 |
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Exceptions to Hardy Weinberg
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Assortive mating
Population Stratification Consanguinity |
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Coefficient of Imbreeding (F)
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Measures the level of consanguinity;
Is the probability that a person who is homozygous at a particular locus inherited both alleles from a single ancestor, or the proportion of loci at which a person is homozygous by descent. Can be calculated by multiplying the propotion of genes two relatives have in common by 1/2. EX: Sibs: 1/2 * 1/2 = 1/4 |
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Coefficient of Impreeding (F) for:
a) Sibs b) Parent - Child c) Half Sibs d) Uncle - niece e) First cousins f) First cousins once removed g) Second cousins |
a) Sibs: 1/4
b) Parent - Child: 1/4 c) Half Sibs: 1/8 d) Uncle - niece: 1/8 e) First cousins: 1/16 f) First cousins once removed: 1/32 g) Second cousins: 1/64 |
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What effect does Selective or Assortive Mating have on Hardy Weinberg?
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Tends to increase the # homozygotes and decrease the # of heterozygotes
-- Acondroplasia + Acondroplasia, Deafness + Deafness, Tall + Tall |
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Fitness (f)
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Probability of transmitting one's genes to the next generation compared to average probability for the population
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Coefficient of selection (s)
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A measure of the loss of fitness
s = 1 - f |
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Equation showing that there is no selection for or against a particular phenotype
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u = q * s
u = mutation rate of the gene q = freq of an allele in the pop s = selection against the allele as selection changes, the frequency of that allele will also change |
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Selection against AD mutations:
a) f = 0 b) f = 1 c) 0 < f < 1 |
a) Complete selection against the mutatation. Eliminated in one generation
b) No deleterious effect on reproduction, no selection against the mutatant allele. s = 0, and virtually all affected inherited the gene from an affected parent (ex: Huntington disease) c) Some affected individuals have an affected parent and some are the result of a new mutation. |
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Genetic Drift
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When the pool of gametes is formed for the next generation, it represents a random sample of alleles from the population, but may vary depending on the sample population you randomly choose. -- more influential in a small population
Founder effects/population bottlenecks are a form of genetic drift |
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Gene flow
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When a population migrates and mates with a new population.
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