BackIn a population of rabbits, f(C₁) = 0.70 and f(C₂) = 0.30. The alleles exhibit an incomplete dominance relationship in which C₁C₁ produces black rabbits, C₁C₂ produces tan-colored rabbits, and C₂C₂ produces rabbits with white fur. If the assumptions of the Hardy–Weinberg principle apply to the rabbit population, what are the expected frequencies of black, tan, and white rabbits?
Sickle cell disease (SCD) is found in numerous populations whose ancestral homes are in the malaria belt of Africa and Asia. SCD is an autosomal recessive disorder that results from homozygosity for a mutant β-globin gene allele. Data on one affected population indicates that approximately 8 in 100 newborn infants have SCD.
What are the frequencies of the wild-type (βᴬ) and mutant (βˢ) alleles in this population?
Sickle cell disease (SCD) is found in numerous populations whose ancestral homes are in the malaria belt of Africa and Asia. SCD is an autosomal recessive disorder that results from homozygosity for a mutant β-globin gene allele. Data on one affected population indicates that approximately 8 in 100 newborn infants have SCD.
What is the frequency of carriers of SCD in the population?
Epidemiologic data on the population in the previous problem reveal that before the application of modern medical treatment, natural selection played a major role in shaping the frequencies of alleles. Heterozygous individuals have the highest relative fitness, and in comparison with heterozygotes, those who are βᴬβᴬ have a relative fitness of 82%, but only about 32% of those with SCD survived to reproduce. What are the estimated equilibrium frequencies of βᴬ and βˢ in this population?
The frequency of tasters and nontasters of PTC varies among populations. In population A, 64% of people are tasters (an autosomal dominant trait) and 36% are nontasters. In population B, tasters are 75% and nontasters 25%. In population C, tasters are 91% and nontasters are 9%.
Calculate the frequency of the dominant (T) allele for PTC tasting and the recessive (t) allele for nontasting in each population.
The frequency of tasters and nontasters of PTC varies among populations. In population A, 64% of people are tasters (an autosomal dominant trait) and 36% are nontasters. In population B, tasters are 75% and nontasters 25%. In population C, tasters are 91% and nontasters are 9%.
Assuming that Hardy–Weinberg conditions apply, determine the genotype frequencies in each population.
In the mouse, Mus musculus, survival in agricultural fields that are regularly sprayed with a herbicide is determined by the genotype for a detoxification enzyme encoded by a gene with two alleles, F and S. The relative fitness values for the genotypes are
Why will this pattern of natural selection result in a stable equilibrium of frequencies of F and S?
In the mouse, Mus musculus, survival in agricultural fields that are regularly sprayed with a herbicide is determined by the genotype for a detoxification enzyme encoded by a gene with two alleles, F and S. The relative fitness values for the genotypes are
Calculate the equilibrium frequencies of the alleles.
In a population of flowers growing in a meadow, C1 and C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with f (C1) = 0.80 and f (C2) = 0.20. Flowers that are C1C1 are yellow, orange flowers are C1C2, and C2C2 flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C1C1 = 0.30, C1C2 = 0.60, and C2C2 = 1.0.
What are the equilibrium frequencies of C1 and C2 if predation continues?
In a population of flowers growing in a meadow, C1 and C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with f(C1) = 0.80 and f(C2) = 0.20. Flowers that are C1C1 are yellow, orange flowers are C1C2, and C2C2 flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C1C1 = 0.30, C1C2 = 0.60, and C2C2 = 1.0.
Assuming the population begins in H-W equilibrium, what are the allele frequencies after one generation of natural selection?
In a population of flowers growing in a meadow, C1 and C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with f (C1) = 0.80 and f (C2) = 0.20. Flowers that are C1C1 are yellow, orange flowers are C1C2, and C2C2 flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C1C1 = 0.30, C1C2 = 0.60, and C2C2 = 1.0.
Assuming random mating takes place among survivors, what are the genotype frequencies in the second generation?
In a population of flowers growing in a meadow, C1 and C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with f (C1) = 0.80 and f (C2) = 0.20. Flowers that are C1C1 are yellow, orange flowers are C1C2, and C2C2 flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C1C1 = 0.30, C1C2 = 0.60, and C2C2 = 1.0.
If predation continues, what are the allele frequencies when the second generation mates?
Assume that the flower population described in the previous problem undergoes a different pattern of predation. Flower-color determination and the starting frequencies of C₁ and C₂ are as described above, but the new insects attack yellow and red flowers, not orange flowers. As a result of the predation pattern, the relative fitness values are C₁C₁ = 0.40, C₁C₂ = 1.0, and C₂C₂ = 0.80.
What are the genotype frequencies among the progeny of predation survivors?
Assume that the flower population described in the previous problem undergoes a different pattern of predation. Flower-color determination and the starting frequencies of C₁ and C₂ are as described above, but the new insects attack yellow and red flowers, not orange flowers. As a result of the predation pattern, the relative fitness values are C₁C₁ = 0.40, C₁C₂ = 1.0, and C₂C₂ = 0.80.
What are the allele frequencies after one generation of natural selection?