Concept explainers
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 to heterozygotes, those who are
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Genetic Analysis: An Integrated Approach (3rd Edition)
- 8% of XY individuals are color blind in a population. Assume Hardy-Weinberg conditions. Submit your answer as it is. a) What is the percentage of color-blind XX individuals? b) What is the percentage of XX individuals who are carriers? c) If this population has 1000 individuals with 50% of male and 50% of female, how many carriers are present in this population? Submit your answer as it is. Do not round up.arrow_forwardThe prevalence (frequency) of sickle-cell disease in Canada is quite low, affecting 1/3800 individuals. However, in some African populations 1/25 individuals are affected by sickle-cell disease. The difference in frequency of this allele within the differing populations has to do with the adaptation pressures that exist in the different environments. Individuals with the heterozygous genotype have a survival advantage in environments where the disease malaria is prevalent as the presence of this mutant allele leads to resistance to malaria. Therefore, the sickle-cell disease tends to be more frequent in environments where the malaria parasite is most common. Question: Explain why the sickle-cell disease remains frequent in some populations while it exists in very low frequency in other populations.arrow_forwardUpon further genetic study of the skunk population, you find the following numbers of haplotypes across the population: AB = 400, Ab = 600, aB = 800, ab = 200. Calculate D (the extent of linkage disequilibrium) for each haplotype. 4) What processes or features might cause the results you observed in part 3 of this question? Give two possibilitiesarrow_forward
- You have collected and determined genotypes of 200 individuals from a population of thr fruit fly, Drosophila pseudoobscura. Your sequencing study revealed 20 individuals with genotype AA, 70 individuals with genotype Aa and 110 individuals with genotype aa. i) what are your theoretical expectations for the number of individuals with each genotype if the population is in Hardy-Weinberg equilibrium. ii) Based on the genotype counts observed, is there evidence that this population of fruit flies deviates from your theoretical expectations under Hardy-Weinberg equilibrium?arrow_forwardAn allele of the G6PD gene acts in a recessive manner to cause sensitivity to fava beans, resulting in ahemolytic reaction (lysis of red blood cells) afteringestion of the beans. The same allele also confersdominant resistance to malaria. The heterozygote hasan advantage in a region where malaria is prevalent.Will the equilibrium frequency (qe) be the same foran African and a North American country? Whatfactors affect qe?arrow_forwardA sample of 100 individuals from a population that is dimorphic at the A locus has genotype counts as follows. AA: 30 Aa: 60 aa: 10 a) What are the allele frequencies in the population? b) What are the expected genotype frequencies, if the population were at HardyWeinberg equilibrium? c) Is the proportion of heterozygotes lower or higher than expected at Hardy-Weinberg equilibrium? What deviations from the assumptions of the model would best explain the observed difference?arrow_forward
- If a disease determined by autosomal recessive heredity occurs at a frequency of 0.04 in a population, what is the frequency of this disease allele in the population? Assume Hardy-Weinberg equilibrium and use Aand a to symbolize the dominant and recessive alleles, respectively. Show calculation.arrow_forwardYou are a scientist studying a population of beetles. Beetle color is controlled by two alleles at a single genetic locus. AA beetles are blue, Aa purple, and aa pink. You count 30 blue beetles, 10 purple beetles, and 40 pink beetles. a) What is the frequency of the A allele? [ Select ] b) What is the observed frequency of the Aa genotype? 1 Select ] c) Under Hardy-Weinberg equilibrium, what is the expected frequency of the aa gentoype? [ Select ] d) Is this beetle population evolving? I Select ]arrow_forwardAn autosomal locus has alleles A and a. The allele frequencies in a population at Hardy Weinberg equilibrium are p = Freq(A) = 0.5 q = Freq(a) = 0.5 What is the frequency of homozygous wild-type (AA) in this population? Enter a single number between 0 and 1, for example, 0.33arrow_forward
- a.)If the frequency of an allele at a locus of interest is 0.57, what is the frequency of the genotype that is homozygous for this allele (that is, that genotype has two copies of this allele)? b.) If we know that the frequency of an allele at a locus of interest is 0.57, we have enough information to calculate the frequency of the related phenotypes in the population, assuming there are only two alleles.arrow_forwardThere are two existing hypotheses for an unusually high frequency of a deleterious recessive allele in a certain population other than it is hidden in the heterozygous genotype and not exposed to selection. Explain what these two likely hypotheses are and how you could distinguish between them based on your understanding of the applicable assumptions that are part of the Hardy-Weinberg Equilibrium Modelarrow_forwardln a population of turtles, there are yellow-green shells and green shells. The yellow shells are caused by a homozygous recessive gene and the green shells are caused by the dominant gene. Given the following data:AA = 340Aa = 270aa = 120 a) Calculate p and q. b) Use a chi square test to determine if these alleles are in Hardy-Weinberg equilibrium. Submit your answer as a pdf or doc file. Show your workarrow_forward
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