EBK BIOLOGY
5th Edition
ISBN: 8220101337627
Author: Maier
Publisher: PEARSON
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Chapter 12, Problem 2AAATB
Summary Introduction
To write:
The PKU is present in the person those are homozygous recessive for this disease allele. The reasons for this disease allele can be present in various frequencies in those populations that can lead to mental retardation in homozygous person.
Introduction:
Genetic drift (allelic drift) can be defined as the variation in the frequency of an existing allele in a population due to an accidental sampling of organisms. Allele frequency of a population is the fraction of the copies of one gene which share a specific form. Reproductive isolation can be defined as the barrier created by the environment, such as a mountain range or river that does not allow mating between two groups of same species.
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Cystic fibrosis is an autosomal recessive disorder that affects 1 in 3 000 newborns with Caucasian background. It causes thick mucus build up in various organs and can cause damages and problems in respiratory and digestive systems.
a) What is the frequency of the cystic fibrosis allele in the Caucasian population? Show all your work and express your answer as a value between 0 and 1 rounded to two decimal places.
b) What percentage of the Caucasian population would be carriers for cystic fibrosis? Show all your work and express your answer rounded to two decimal places.
c)If two individuals are carriers of the cystic fibrosis allele, what is the probability that they would have a girl without cystic fibrosis? Show all your work (including the Punnett square) and express your answer as a value between 0 and 1 rounded to two decimal places.
Sickle cell anemia is caused by a recessive allele at a single gene. As we discussed in class, being a homozygote for the sickle cell allele is almost always lethal, but heterozygotes tend to be resistant against malaria although they have a mild form of anemia. Because of this heterozygote advantage, the allele for sickle cell anemia has a frequency of more than 10% in some human populations.
How would present allele frequencies of the sickle cell allele change, if there was no heterozygote advantage or disadvantage (that is, that heterozygotes would be identical to ‘normal’ homozygotes – no malaria resistance, no anemia)? How would the change in sickle cell allele frequencies compare to scenario a (extirpation of malaria)
Below in Figure 1 is a pedigree for a family afflicted by a genetic disorder. In some populations, Cystic fibrosis has an incidence of 1 in 2500 newborns. The carrier frequency calculated from this is 1/25. Analyze the pedigree below assuming the disease is similar to cystic fibrosis in incidence and carrier frequency. However this disease may not have the same type of genetic transmission as cystic fibrosis.
What type of genetic transmission is most consistent with the pedigree?
Label all the individuals that you can determine, with hypothesized genotypes.
Label the individuals that have unknown genotypes with possible genotypes.
Assuming her father is known to NOT be a carrier, calculate the probability that IV1 is a carrier for disease.
Use the Χ2 test to determine whether your proposed transmission fits this data.
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- Below in Figure 1 is a pedigree for a family afflicted by a genetic disorder. In some populations, Cystic fibrosis has an incidence of 1 in 2500 newborns. The carrier frequency calculated from this is 1/25. Analyze the pedigree below assuming the disease is similar to cystic fibrosis in incidence and carrier frequency. However this disease may not have the same type of genetic transmission as cystic fibrosis. What type of genetic transmission is most consistent with the pedigree? Label all the individuals that you can determine, with hypothesized genotypes. Label the individuals that have unknown genotypes with possible genotypes. Assuming her father is known to NOT be a carrier, calculate the probability that IV1 is a carrier for disease. Use the Χ2 test to determine whether your proposed transmission fits this data.arrow_forwardOne particularly useful feature of the Hardy-Weinberg equation is that it allows us to estimate the frequency of heterozygotes for recessive genetic diseases, assuming that Hardy-Weinberg equilibrium exists. As an example, let’s consider cystic fibrosis, which is a human genetic disease involving a gene that encodes a chloride transporter. Persons with this disorder have an irregularity in salt and water balance. One of the symptoms is thick mucus in the lungs that can contribute to repeated lung infections. In populations of Northern European descent, the frequency of affected individuals is approximately 1 in 2500. Because this is a recessive disorder, affected individuals are homozygotes. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of individuals who are heterozygous carriers?arrow_forwardA research team genotyped hundreds of families affected by haemophilia. Among those families, they found many that had a pattern of RFLP like that of daughter1, her husband and her parents. When they genotyped the children in those families, they found the following association between the RFLP and hemophilia: The numbers at the bottom indicate the number of progeny with that combination of hemophilia phenotype and RFLP polymorphism found among these families. What is the map distance between the RFLP and the hemophilia gene? Show your work.arrow_forward
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- Below in Figure 1 is a pedigree for a family afflicted by a genetic disorder. In some populations, Cystic fibrosis has an incidence of 1 in 2500 newborns. The carrier frequency calculated from this is 1/25. Analyze the pedigree below assuming the disease is similar to cystic fibrosis in incidence and carrier frequency. However this disease may not have the same type of genetic transmission as cystic fibrosis. Assuming her father is known to NOT be a carrier, calculate the probability that IV1 is a carrier for disease. Use the Χ2 test to determine whether your proposed transmission fits this data.arrow_forwardSix single-nucleotide polymorphism (SNP) loci are known to contribute to the development of type 2 diabetes. Diabetes is certain if eight or more of the alleles at these six loci are of the “contributing” variety. An uppercase letter indicates an allele that contributes to diabetes and a lowercase symbol indicates a noncontributing allele. A married couple wants to know the probability of producing a child who is at severe risk of type 2 diabetes. Their genotypes were determined by microarray analysis and are as follows: AaBbccDDEEFf × AaBbCCDdEeFfarrow_forwardCystic fibrosis (CF) is an autosomal recessive trait. A three-generation pedigree is shown below for a family that carries the mutant allele for cystic fibrosis. Note that carriers are not colored in to allow you to figure out their genotypes. Normal allele = F CF mutant allele = f What is the genotype of individual #13? A) ff B) FF C) Ff D) it is impossible to tellarrow_forward
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