Essentials of Genetics (9th Edition) - Standalone book
9th Edition
ISBN: 9780134047799
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino
Publisher: PEARSON
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Chapter 3, Problem 2CS
CASE STUDY | To test or not to test
Thomas first discovered a potentially devastating piece of family history when he learned the medical diagnosis for his brother's increasing dementia, muscular rigidity, and frequency of seizures. His brother, at age 49, was diagnosed with Huntington disease (HD), a dominantly inherited condition that typically begins with such symptoms around the age of 45 and leads to death in one's early 60s. As depressing as the news was to Thomas, it helped explain his father's suicide. Thomas, 38, now wonders what his chances are of carrying the gene for HD, leading him and his wife to discuss the pros and cons of him undergoing genetic testing. Thomas and his wife have two teenage children, a boy and a girl.
How might the preparation and analysis of a pedigree help explain the dilemma facing Thomas and his family?
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Students have asked these similar questions
40
Below is a pedigree of a family, some of whom have the autosomal dominant condition Huntington's disease.
Affected individuals are indicated by a dark square or circle. The male in generation I (indicated by the arrow) is
heterozygous for the Huntington's disease mutation.
The following two questions relate to this pedigree.
Generation
II
II
If H represents the disease allele, and h the wild type allele, what is the genotype of the individual indicated by the
*?
Select one alternative:
O hh
O Hh
O hH
O HH
Question:
The disorder: Red-Green color blindness
Explain the mode of inheritance of the disorder (recessive, dominant, x-linked, etc.)
. Can a person be a carrier of this disorder?
• Describe the probability of having a child with the disorder -- give a specific scenario (ex. both parents are heterozygous for
the trait)
• Describe the symptoms associated with this disorder
Explain the prognosis of a person born with this disorder
tion 8:
below is the pedigree of inheritance of phenylketonuria (PKU). We will designate the letter
Caven
for the dominant allele and "p" for the recessive allele.
4
The pedigree shows that the pattern of inheritance for the allele for
phenylk
ylketonuria is:
I.
II.
1
III.
IV.
Autosomal dominant
Autosomal recessive
X-linked dominant
X-linked recessive
b. The parents in generation I have how many children:
I.
3 Boys
II.
3 Girls
III.
IV.
3 Boys and 1 Girl
3 Girls and 1 Boy
c. What is the genotype of individual 1 in generation III:
I. PP
II. pp
III. Pp
" O
1
III. 50%
E
III
1
▬
2
2
IV. 25%
1
3
IV. Can be PP or Pp
ii. Suppose that a man having type AB blood marries a woman having type O blood. What is the
probability that their child will have type A blood?
I. 100%
II. 75%
2
4
3
Chapter 3 Solutions
Essentials of Genetics (9th Edition) - Standalone book
Ch. 3 -
CASE STUDY | To test or not to test
Thomas...Ch. 3 -
CASE STUDY | To test or not to test
Thomas...Ch. 3 - CASE STUDY | To test or not to test Thomas first...Ch. 3 -
CASE STUDY | To test or not to test
Thomas...Ch. 3 - When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...
Ch. 3 - When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 -
When working out genetics problems in this and...Ch. 3 - When working out genetics problems in this and...Ch. 3 - Prob. 26PDQCh. 3 -
When working out genetics problems in this and...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- Question:- Based on your selected mode of inheritance, show the genotypes for the following individuals. [Use these symbols for alleles: if it is autosomal, then use the symbols B - dominant, b - recessive (e.g. BB, bb etc.) if it is X-Linked, then X(B) - dominant, X(b) - recessive, and Y for Y-chromosome (e.g. X(B)X(B), X(B)Y etc.) ] I-1 I-2 II-7 II-8 III-10 III-11 III-12 IV-8 IV-9arrow_forwardMike was referred for genetic counseling because he was concerned about his extensive family history of colon cancer. That family history was highly suggestive of hereditary nonpolyposis colon cancer (HNPCC). This predisposition is inherited as an autosomal dominant trait, and those who carry the mutant allele have a 75% chance of developing colon cancer by age 65. Mike was counseled about the inheritance of this condition, the associated cancers, and the possibility of genetic testing (on an affected family member). Mikes aunt elected to be tested for one of the genes that may be altered in this condition and discovered that she did have an altered MSH2 gene. Other family members are in the process of being tested for this mutation. Once a family member is tested for the mutant allele, is it hard for other family members to remain unaware of their own fate, even if they did not want this information? How could family dynamics help or hurt this situation?arrow_forwardMike was referred for genetic counseling because he was concerned about his extensive family history of colon cancer. That family history was highly suggestive of hereditary nonpolyposis colon cancer (HNPCC). This predisposition is inherited as an autosomal dominant trait, and those who carry the mutant allele have a 75% chance of developing colon cancer by age 65. Mike was counseled about the inheritance of this condition, the associated cancers, and the possibility of genetic testing (on an affected family member). Mikes aunt elected to be tested for one of the genes that may be altered in this condition and discovered that she did have an altered MSH2 gene. Other family members are in the process of being tested for this mutation. Is colon cancer treatable? What are the common treatments, and how effective are they?arrow_forward
- Mike was referred for genetic counseling because he was concerned about his extensive family history of colon cancer. That family history was highly suggestive of hereditary nonpolyposis colon cancer (HNPCC). This predisposition is inherited as an autosomal dominant trait, and those who carry the mutant allele have a 75% chance of developing colon cancer by age 65. Mike was counseled about the inheritance of this condition, the associated cancers, and the possibility of genetic testing (on an affected family member). Mikes aunt elected to be tested for one of the genes that may be altered in this condition and discovered that she did have an altered MSH2 gene. Other family members are in the process of being tested for this mutation. Seventy-five percent of people who carry the mutant allele will get colon cancer by age 65. This is an example of incomplete penetrance. What could cause this?arrow_forwardA 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?arrow_forwardA 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 is the chance that this couple will have a child with two copies of the dominant mutant gene? What is the chance that the child will have normal height?arrow_forward
- 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?arrow_forward2) Indicate the pattern of inheritance for the human genetic disorders. Use letter symbols for your answers (AR, AD, XR,XD, M) where appropriate. Table 2. HUMAN GENETIC DISORDER PATTERN OF INHERITANCE Marfan Syndrome Sickle Cell Anemia Classical Hemophilia Hypophosphatemia Cystic Fibrosis Phenylketonuria Huntington’s Disease Tay Sachs Disease Neurofibromatosis Alkaptonuria Xeroderma pigmentosum Kearns-Sayre Syndrome Achondroplasia Beta thalassemia Duchene Muscular Dystrophyarrow_forwardAav AaBbCc Normal No Spacing Heading 1 Paragraph Styles In man, two abnormal conditions, cataracts (C) in the eyes and excessive fragility (F) in the bones, seem to depend on separate dominant genes located on different chromosomes. Normal vision and normal bones are recessive traits. A man with cataracts and nomal bones, whose father had normal eyes, married a woman free from cataracts but with fragile bones. Her father had normal bones. 11. What is the genotype of the man with cataracts and nomal bones? What is the genotype of the woman with normal vision and fragile bones? What type of offspring might this couple expect? Genotypes Phenotypes What is the probability that their first child will, (a) be free from both abnormalities (b) have cataracts but not fragile bones (c) have fragile bones but not cataracts (d) have both cataracts and fragile bones? liliarrow_forward
- 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?arrow_forwardQuestion:- 8. Describe how Morgan’s experiment with the white-eyed mutant fly provided evidence for the chromosomal basis for inheritance. Be sure to include the significance of the x-linked gene.arrow_forwardTOPIC: Sex-linked inheritance Glucose-6-phosphate dehydrogenase deficiency/G6PDD (g) is an X-linked recessive condition wherein the red blood cells of affected individuals undergo premature hemolysis. Fragile X syndrome (F), on the other hand, is an X-linked dominant mutation characterized by a mild to moderate intellectual disability. Amelogenesis imperfecta (AMELY) (A) is a sex-linked congenital disorder affecting the formation of the teeth enamel making affected individuals at higher risk for dental cavities and related problems. Only male offspring inherit this condition. Jane is heterozygous for both X-linked traits like her mother. Her father is normal for both X-linked traits. James has a mother who suffers from G6PDD but not from fragile X-syndrome. His father does not exhibit any X-linked disorder but has amelogenesis imperfecta. What are the genotypes of the following: Jane: ________ James: _________ Jane’s mother: __________…arrow_forward
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