Concept explainers
Tay-Sachs disease is an autosomal recessive neurological disorder that is fatal in infancy. Despite its invariably lethal effect, Tay
a. What is a genetic bottleneck?
b. Explain how a genetic bottleneck and its aftermath could result in a population that carries a lethal allele in high frequency
c. In the population described, what is the frequency of the recessive allele that produces Tay
d. Assuming mating occurs at random in this population, what is the probability a couple are both carriers of Tay
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Genetic Analysis: An Integrated Approach (3rd Edition)
- Cystic fibrosis is a genetic disease mostly affecting people of European descent that is caused by a recessive allele. You sample 1000 people for this allele and find 772 homozygous normal individuals, 221 heterozygotes, and 7 people homozygous for cystic fibrosis. Is this population in Hardy-Weinberg equilibrium?arrow_forwardIf the frequency of those exhibiting a monogenic autosomal recessive phenotype caused by a rare clinically relevant allele is 1/8500 in a given population, what is the carrier frequency? Please give your answer as a percentage to 3 decimal places, do not include the % symbol. ANSWER: In a population where the frequency of those exhibiting a monogenic autosomal recessive phenotype caused by only one known mutation is 1/8500 the carrier frequency is a percent.arrow_forwardA mountain region has a population of 5,000 mountain goats. You score these animals for the R locus and find that this locus has two alleles, R (dominant) and r (recessive). 3200 individuals are homozygous dominant, 1,600 are heterozygous, and 200 are homozygous recessive. A deadly virus infects all of the RR mountain goats in the population (above), killing all individuals of this genotype and leaving the population with only the rr and Rr mountain goats. a) Calculate the new allele frequencies for this population. Show your work. b) Calculate the new (observed) genotypic frequencies for this population. Show your work. c) Does this population still appear to be at H-W equilibrium? Why or why not? (You do not need to analyze this statistically).arrow_forward
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- Tay-Sachs disease is a recessive genetic disease. Individuals with this disease rarely survive past the age of four. In the general population, approximately 1 person in 300 carries the allele for this disease. However, in some populations, including the Irish Americans, the Ashkenazi Jews and the Cajuns from Louisiana, the proportion of Tay-Sachs carriers is much higher (1 in 27 to 1 in 50) than in other populations. Which evolutionary scenario can be predicted to produce a high frequency of Tay-Sachs disease in these populations? Select one: a. All three populations descend from a small number of settlers b. The Tay-Sachs allele is advantageous at the heterozygous state c. These populations experienced disruptive selection d. These populations experienced stabilizing selection e. These populations have higher than average mutation ratesarrow_forwardThere are 150 dominant homozygotes, 100 heterozygotes, and 50 recessive homozygotes in a population. How many dominant and how many recessive alleles are in this population? What would be there respective allele frequencies?arrow_forwardA certain autosomal recessive trait occurs in a population with a frequency of 1 in 6000. what is the expected frequency of heterozygous carriers in this population? (Assume the population is in Hardy-Weinberg equilibrium)arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning