The pedigree below shows the expression of Huntington's disease in a family. Huntington's disease is a fatal genetic disorder that causes the progressive nerve cells in the brain. It deteriorates a person's physical and mental abilities usually during their prime working years and has no cure. Huntington's is inherited as a dominant allele (H). Examine the pedigree below and determine the genotype for individual "4". O HH O Hh O h O either HH or Hh

The pedigree below shows the expression of Huntington's disease in a family. Huntington's disease is a fatal genetic disorder that causes the progressive nerve cells in the brain. It deteriorates a person's physical and mental abilities usually during their prime working years and has no cure. Huntington's is inherited as a dominant allele (H). Examine the pedigree below and determine the genotype for individual "4". O HH O Hh O h O either HH or Hh

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter4: Pedigree Analysis In Human Genetics

Section: Chapter Questions

Problem 21QP: Analysis of X-Linked Dominant and Recessive Traits As a genetic counselor investigating a genetic...

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A couple was referred for genetic counseling because they wanted to know the chances of having a child with dwarfism. Both the man and the woman had achondroplasia (MIM 100800), the most common form of short-limbed dwarfism. The couple knew that this condition is inherited as an autosomal dominant trait, but they were unsure what kind of physical manifestations a child would have if it inherited both mutant alleles. They were each heterozygous for the FGFR3 (MIM 134934) allele that causes achondroplasia. Normally, the protein encoded by this gene interacts with growth factors outside the cell and receives signals that control growth and development. In achrodroplasia, a mutation alters the activity of the receptor, resulting in a characteristic form of dwarfism. Because both the normal and mutant forms of the FGFR3 protein act before birth, no treatment for achrondroplasia is available. The parents each carry one normal allele and one mutant allele of FGRF3, and they wanted information on their chances of having a homozygous child. The counsellor briefly reviewed the phenotypic features of individuals with achondroplasia. These include facial features (large head with prominent forehead; small, flat nasal bridge; and prominent jaw), very short stature, and shortening of the arms and legs. Physical examination and skeletal X-ray films are used to diagnose this condition. Final adult height is approximately 4 feet. Because achondroplasia is an autosomal dominant condition, a heterozygote has a 1-in-2, or 50%, chance of passing this trait to his or her offspring. However, about 75% of those with achondroplasia have parents of average size who do not carry the mutant allele. In these cases, achondroplasia is due to a new mutation. In the couple being counseled, each individual is heterozygous, and they are at risk for having a homozygous child with two copies of the mutated gene. Infants with homozygous achondroplasia are either stillborn or die shortly after birth. The counselor recommended prenatal diagnosis via ultrasounds at various stages of development. In addition, a DNA test is available to detect the homozygous condition prenatally. Should the parents be concerned about the heterozygous condition as well as the homozygous mutant condition?
A couple was referred for genetic counseling because they wanted to know the chances of having a child with dwarfism. Both the man and the woman had achondroplasia (MIM 100800), the most common form of short-limbed dwarfism. The couple knew that this condition is inherited as an autosomal dominant trait, but they were unsure what kind of physical manifestations a child would have if it inherited both mutant alleles. They were each heterozygous for the FGFR3 (MIM 134934) allele that causes achondroplasia. Normally, the protein encoded by this gene interacts with growth factors outside the cell and receives signals that control growth and development. In achrodroplasia, a mutation alters the activity of the receptor, resulting in a characteristic form of dwarfism. Because both the normal and mutant forms of the FGFR3 protein act before birth, no treatment for achrondroplasia is available. The parents each carry one normal allele and one mutant allele of FGRF3, and they wanted information on their chances of having a homozygous child. The counsellor briefly reviewed the phenotypic features of individuals with achondroplasia. These include facial features (large head with prominent forehead; small, flat nasal bridge; and prominent jaw), very short stature, and shortening of the arms and legs. Physical examination and skeletal X-ray films are used to diagnose this condition. Final adult height is approximately 4 feet. Because achondroplasia is an autosomal dominant condition, a heterozygote has a 1-in-2, or 50%, chance of passing this trait to his or her offspring. However, about 75% of those with achondroplasia have parents of average size who do not carry the mutant allele. In these cases, achondroplasia is due to a new mutation. In the couple being counseled, each individual is heterozygous, and they are at risk for having a homozygous child with two copies of the mutated gene. Infants with homozygous achondroplasia are either stillborn or die shortly after birth. The counselor recommended prenatal diagnosis via ultrasounds at various stages of development. In addition, a DNA test is available to detect the homozygous condition prenatally. What if the couple wanted prenatal testing so that a normal fetus could be aborted?
Achondroplasia is a rare dominant autosomal defect resulting in dwarfism. The unaffected brother of an individual with achondroplasia is seeking counsel on the likelihood of his being a carrier of the mutant allele. What is the probability that the unaffected client is carrying the achondroplasia allele?
A pedigree analysis was performed on the family of a man with schizophrenia. Based on the known concordance statistics, would his MZ twin be at high risk for the disease? Would the twins risk decrease if he were raised in an environment different from that of his schizophrenic brother?
Analysis of X-Linked Dominant and Recessive Traits As a genetic counselor investigating a genetic disorder in a family, you are able to collect a four-generation pedigree that details the inheritance of the disorder in question. Analyze the information in the pedigree to determine whether the trait is inherited as: a. autosomal dominant b. autosomal recessive c. X-linked dominant d. X-linked recessive e. Y-linked
Familial retinoblastoma, a rare autosomal dominant defect, arose in a large family that had no prior history of the disease. Consider the following pedigree (the darkly colored symbols represent affected individuals): a. Circle the individual(s) in which the mutation most likely occurred. b. Is the person who is the source of the mutation affected by retinoblastoma? Justify your answer. c. Assuming that the mutant allele is fully penetrant, what is the chance that an affected individual will have an affected child?
Analysis of Autosomal Recessive and Dominant Traits Describe the phenotype and primary gene or protein defect of the X-linked recessive disease muscular dystrophy.
Variations in Phenotype Expression Define penetrance and expressivity.
Clubfoot is a common congenital birth defect. This defect is caused by a number of genes but appears to be phenotypically distributed in a noncontinuous fashion. Geneticists use the threshold model to explain the occurrence of this defect. Explain this model. Explain predisposition to the defect in an individual who has a genotypic liability above the threshold versus an individual who has a liability below the threshold.
Let us practice it again! Analyze the pedigree below to answer the questions that follow. Huntington's disease a disorder in which nerve cells waste away, or disintegrate, is passed down through families. certain parts of the brain Huntington's diseate llustration ereated in htps://pregenygenetion.com/ 1. What members of the family above are affected with the Huntington's disease? 2. Tnere are no carriers ior Huntungton's disease you either have it or you do not. Is Huntington's disease caused-by a dominant or recessive trait? 3. Identify the genotypes of the following individuals using the pedigree above. (homozygous dominant, homozygous recessive, heterozygous). I- 1 II -1: II -3: III - 4 : 4. How many children did individuals I-1 and I-2 have? 5. How many girls did II-1 and II-2 have? How many have Huntington's Disease? 6. How are individuals III-2 and II-4 related? I-2 and III-5?
please use punnett squares
Hereditary hemochromatosis is an autosomal recessive genetic disorder that causes the body to absorb too much iron from the diet. This excess iron is stored in the body's tissues and organs, particularly the skin, heart, liver, pancreas, and joints. Because humans cannot increase the excretion of iron, excess iron can overload and eventually damage tissues and organs. Q. A man who had hemophilia (an X-linked recessive genetic disorder), married a woman who had no family history of hemophilia whatsoever. The couple had consulted a genetic counselor when they first contemplated having children due to concerns that their future children might have hemophilia. Genetic testing of both future parents revealed that the husband did, in fact, possess the Hemophilia A allele but his wife was completely normal with respect to hemophilia. Much to their shock, their first child, a daughter, had a mild blood clotting disorder. Karyotyping was performed to determine whether this daughter had an…