Concept explainers
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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Biology: Science for Life with Physiology (5th Edition)
- 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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- Sickle cell anemia is a genetically inherited autosomal recessive trait in which results in a condition that there are not enough healthy red blood cells to carry oxygen throughout the body due to the production of red blood cells that are sickle shaped. The frequency of the sickle cell condition is as high as 10% in Central Africa compared to 0.5% in the United States. Calculate the frequency of the normal and carries of the sickle cell condition.arrow_forwardHuntington's disease is a very rare, debilitating disease that affects approximately 1 in 10,000 people. The disease is caused by a particular type of genetic mutation (large number of CAG repeats) in a gene called huntingtin (HTT). Designate the disease-causing allele HTTP and the non-disease- causing allele HTTN. We know that individuals with genotype HTTN will not develop Huntington's Disease, but people with either HTTD/HTTP or HTTN/HTTD will develop the disease. Which allele is dominant--HTTN or HTTP? Explain your reasoning thoroughly, using the correct definition of dominance.arrow_forwardCystic Fibrosis (CF) is an autosomal recessive condition. Therefore, heterozygous (Cc) carriers do not display symptoms. Two parents who are carriers plan to start a family and you are a genetic counselor helping to advise them about their chances of having children affected by CF. a) Suppose the couple has 4 children, each one year apart. What is the probability that all 4 children will inherit CF? b) What is the probability that any 3 of their 4 children will not inherit CF, but 1 will be affected? c) What is the probability that their first child will not inherit CF, but the younger 3 children will inherit CF?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning