EBK BIOLOGY
6th Edition
ISBN: 9780134819150
Author: Maier
Publisher: VST
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Chapter 13, Problem 2AAATB
Summary Introduction
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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)
A 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.
Chapter 13 Solutions
EBK BIOLOGY
Ch. 13 - Define biological species.Ch. 13 - Prob. 2LTBCh. 13 - Prob. 3LTBCh. 13 - Prob. 4LTBCh. 13 - Prob. 5LTBCh. 13 - Prob. 6LTBCh. 13 - The biological definition of race corresponds to...Ch. 13 - All of the following statements support the...Ch. 13 - Similarity in skin color among different human...Ch. 13 - Prob. 10LTB
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- Sickle cell anemia is a genetic disease most common in those of African ancestry that results from the mutation of a single basepair. This mutation results in a change to the hemoglobin protein. In this experiment, “S” will represent the normal allele and “s” thesickle allele. They are codominant alleles. Therefore, SS is normal, Ss is not fatal but mildly symptomatic, and ss is debilitating,painful, and often fatal. After hundreds or even thousands of generations, both alleles are still common in those of African ancestry. How would you explain this?arrow_forwardNiemann Pick Type C disease is a recessive disorder that causes the accumulation of cholesterol and other lipids in lysosomes, ultimately affecting both the liver and the nervous system. Below are the genotypes and phenotypes of offspring of a family with a history of Niemann Pick. 7 NN ( all normal phenotype) 3 Nn (all normal phenotype) 4 nn (1 early onset dementia, 1 mid-life onset dementia, 2 late-onset dementia). From this information, Niemann-Pick disease is an example of: A) variable expressivity B) incomplete dominance C) incomplete penetrance D) variable expressivity and incomplete penetrance E) multiple allelesarrow_forwardCystic fibrosis is an autosomal recessive disease characterized by two copies of a mutated CFTR gene. If one in 100 (hypothetical scenario, not reality) people in the United States have cystic fibrosis, calculate the p and q frequency for the normal allele (p) and the mutated allele (q). Based on those calculations, what percentage of individuals would be expected to be homozygous dominant?arrow_forward
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