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What is one of the main reasons we use the Hardy-Weinberg Equilibrium Principle?
What is one of the main reasons we use the Hardy-Weinberg Equilibrium Principle?
What is one of the assumptions of the Hardy-Weinberg Equilibrium Principle?
What is one of the assumptions of the Hardy-Weinberg Equilibrium Principle?
What can be predicted using the Hardy-Weinberg Equilibrium Principle, given the allele frequencies?
What can be predicted using the Hardy-Weinberg Equilibrium Principle, given the allele frequencies?
What happens to the allele and genotype frequencies if the assumptions of the Hardy-Weinberg Equilibrium Principle are met?
What happens to the allele and genotype frequencies if the assumptions of the Hardy-Weinberg Equilibrium Principle are met?
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What is an example of a dominant trait in cats, as discussed in the context of the Hardy-Weinberg Equilibrium Principle?
What is an example of a dominant trait in cats, as discussed in the context of the Hardy-Weinberg Equilibrium Principle?
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What is the name of the equation that describes the genotype frequencies in a population, according to the Hardy-Weinberg Equilibrium Principle?
What is the name of the equation that describes the genotype frequencies in a population, according to the Hardy-Weinberg Equilibrium Principle?
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What is the frequency of genotype AA in the given example?
What is the frequency of genotype AA in the given example?
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What is the condition for a population to be in Hardy-Weinberg Equilibrium?
What is the condition for a population to be in Hardy-Weinberg Equilibrium?
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What is the frequency of allele A in the next generation, given the example?
What is the frequency of allele A in the next generation, given the example?
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What is the implication of a population being in Hardy-Weinberg Equilibrium?
What is the implication of a population being in Hardy-Weinberg Equilibrium?
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What is the formula for the frequency of genotype AB in the general case?
What is the formula for the frequency of genotype AB in the general case?
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What is the sum of the allele frequencies in a population?
What is the sum of the allele frequencies in a population?
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What is the conclusion about the genotype frequencies in a population in Hardy-Weinberg Equilibrium?
What is the conclusion about the genotype frequencies in a population in Hardy-Weinberg Equilibrium?
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What is the assumption about the population in the Hardy-Weinberg Equilibrium principle?
What is the assumption about the population in the Hardy-Weinberg Equilibrium principle?
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What is evolution in terms of Hardy-Weinberg?
What is evolution in terms of Hardy-Weinberg?
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What does Hardy-Weinberg equilibrium imply about a population?
What does Hardy-Weinberg equilibrium imply about a population?
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What statistical test is used to determine if a population is in Hardy-Weinberg equilibrium?
What statistical test is used to determine if a population is in Hardy-Weinberg equilibrium?
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What is the consequence of violating the 'no selection' assumption in Hardy-Weinberg equilibrium?
What is the consequence of violating the 'no selection' assumption in Hardy-Weinberg equilibrium?
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What is a key requirement for the Hardy-Weinberg equations to be used?
What is a key requirement for the Hardy-Weinberg equations to be used?
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What is a consequence of random mating in a population?
What is a consequence of random mating in a population?
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Study Notes
Hardy-Weinberg Equilibrium Principle
- The Hardy-Weinberg Equilibrium Principle is used to show that evolution does not happen under certain conditions.
- It provides a set of testable assumptions, and if any of these assumptions are violated, the conclusions do not hold.
- It serves as a null model to test evolution against.
Assumptions of Hardy-Weinberg
- There is no selection, meaning all members contribute equally to the gene pool.
- There is no mutation, meaning no new alleles are created.
- There is no migration, meaning all alleles stay in the gene pool.
- The population size is infinitely large, meaning no random events or genetic drift occur.
- Mates are chosen randomly (panmixia).
Why Use Hardy-Weinberg?
- It allows for the prediction of genotype frequencies given allele frequencies.
- Genotypes will approximate a binomial distribution after one generation of random mating.
- If allele frequencies are known, genotype frequencies can be predicted.
- Allele and genotype frequencies will not change as long as the assumptions are met.
Dominance and Hardy-Weinberg
- A simple phenotypic example of dominance is polydactyly in cats, caused by a variant of the Pd gene.
- In a population of 100 cats, if 60 are polydactyl and 40 are normal, the genotype frequencies can be calculated using the Hardy-Weinberg Equilibrium Principle.
Numerical Example
- Using the Hardy-Weinberg Equilibrium Principle, the genotype frequencies can be calculated:
- AA: 0.36
- Aa: 0.48
- aa: 0.16
- The allele frequencies in the next generation can be calculated:
- Frequency of A: 0.6
- Frequency of a: 0.4
General Case
- A single locus with alleles A and B has three possible diploid genotypes: AA, AB, and BB.
- The frequency of allele A is p, and the frequency of allele B is q, where p + q = 1.
- The genotype frequencies can be calculated using the Hardy-Weinberg Equilibrium Principle:
- AA: p²
- AB: 2pq
- BB: q²
Conclusions
- The allele frequencies in a population will not change, generation after generation.
- If the allele frequencies in a population are given by p and q, the genotype frequencies will be given by p², 2pq, and q².
- A population in Hardy-Weinberg Equilibrium is not evolving.
Testing Hardy-Weinberg Equilibrium
- The Chi-squared test is used to determine if the Hardy-Weinberg Equilibrium holds or is broken.
- The test formula is: χ² = Σ((observed – expected)² / expected).
- The degrees of freedom is 1, and critical values can be looked up online or in a statistics textbook.
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Description
This quiz covers the Hardy-Weinberg Equilibrium Principle, its assumptions, and its importance in understanding evolution. It explains why this principle is used and what happens when its assumptions are violated.
