Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Chapter 2, Problem 40P
Figure 2.22 shows the inheritance of Huntington disease in a family from a small village near Lake Maracaibo in Venezuela. The village was founded by a small number of immigrants, and generations of their descendants have remained concentrated in this isolated location. The allele for Huntington disease has remained unusually prevalent there.
| a. | Why could you not conclude definitively that the disease is the result of a dominant or a recessive allele solely by looking at this pedigree? |
| b. | Is there any information you could glean from the family’s history that might imply the disease is due to a dominant rather than a recessive allele? |
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A couple who are about to get married learn from studying their family histories that, in both their families, theirunaffected grandparents had siblings with cystic fibrosis(a rare autosomal recessive disease).a. If the couple marries and has a child, what is theprobability that the child will have cystic fibrosis?b. If they have four children, what is the chance that thechildren will have the precise Mendelian ratio of 3:1 fornormal:cystic fibrosis?c. If their first child has cystic fibrosis, what is theprobability that their next three children will be normal?
In classical Mendelian genetics, how can one check the genotype of a parent (A) expressing the characters of a dominant allele?
Select one:
a.
By performing a back cross with a recessive homozygote parent (B). If the A parent is homozygote for the dominant allele, then all the individuals from the F1 will display the dominant character. If the parent A was, instead, a heterozygote, then 50% of the F1 progeny will express the recessive character (homozygote recessive) and 50% the dominant one (heterozygotes).
b.
It is impossible to check such genotype without using specific molecular assays.
c.
By performing a back cross with a dominant homozygote parent (B). If the A parent is homozygote for the dominant allele, then all the individuals from the F1 will display the dominant character.
The pedigree below shows three generations of a family that carries albinism, an autosomal recessive genetic disease. In the third generation, a child was born with albinism but the genotypes of the rest of the family are unknown. No other family members have the disease. Assume normal, Mendelian genetics with no new mutations. What are the genotypes of the parents of the affected child?
A) There is not enough information to determine their genotypes
B) Both are homozygous for albinism
C) One is hemizygous and one is heterozygous for albinism
D) Both are heterozygous for albinism
E) One is homozygous and one is heterozygous for abinism
Chapter 2 Solutions
Genetics: From Genes to Genomes
Ch. 2 - For each of the terms in the left column, choose...Ch. 2 - During the millennia in which selective breeding...Ch. 2 - Describe the characteristics of the garden pea...Ch. 2 - An albino corn snake is crossed with a...Ch. 2 - Two short-haired cats mate and produce six...Ch. 2 - Piebald spotting is a condition found in humans in...Ch. 2 - As a Drosophila research geneticist, you keep...Ch. 2 - A mutant cucumber plant has flowers that fail to...Ch. 2 - In a particular population of mice, certain...Ch. 2 - In humans, a dimple in the chin is a dominant...
Ch. 2 - Some inbred strains of the weedy plant Arabidopsis...Ch. 2 - Among Native Americans, two types of earwax...Ch. 2 - Imagine you have just purchased a black stallion...Ch. 2 - If you roll a die singular of dice, what is the...Ch. 2 - In a standard deck of playing cards, four suits...Ch. 2 - How many genetically different eggs could be...Ch. 2 - What is the probability of producing a child that...Ch. 2 - A mouse sperm of genotype a B C D E fertilizes an...Ch. 2 - Your friend is pregnant with triplets. She thinks...Ch. 2 - Galactosemia is a recessive human disease that is...Ch. 2 - Albinism is a condition in which pigmentation is...Ch. 2 - A cross between two pea plants, both of which grew...Ch. 2 - A third-grader decided to breed guinea pigs for...Ch. 2 - The self-fertilization of an pea plant produced...Ch. 2 - The achoo syndrome sneezing in response to bright...Ch. 2 - A pea plant from a pure-breeding strain that is...Ch. 2 - The following table shows the results of different...Ch. 2 - A pea plant heterozygous for plant height, pod...Ch. 2 - In the fruit fly Drosophila melanogaster, the...Ch. 2 - Based on the information you discovered in the...Ch. 2 - Considering the yellow and green pea color...Ch. 2 - What would have been the outcome the genotypic and...Ch. 2 - Recall that Mendel obtained pure-breeding with...Ch. 2 - The gene that likely controlled flower color...Ch. 2 - For each of the following human pedigrees,...Ch. 2 - Consider the pedigree that follows for cutis laxa,...Ch. 2 - A young couple went to see a genetic counselor...Ch. 2 - Huntington disease is a rare fatal, degenerative...Ch. 2 - Is the disease shown in the following pedigree...Ch. 2 - Figure 2.22 shows the inheritance of Huntington...Ch. 2 - Consider the cystic fibrosis pedigree in Figure...Ch. 2 - Prob. 42PCh. 2 - People with nail-patella syndrome have poorly...Ch. 2 - Midphalangeal hair hair on top of the middle...Ch. 2 - A man with Huntington disease he is heterozygous...Ch. 2 - Explain why disease alleles for cystic fibrosis CF...Ch. 2 - The following pedigree shows the inheritance of...
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- The following pedigree shows the pattern of inheritance of red-green color blindness in a family. Females are shown as circles and males as squares; the squares or circles of individuals affected by the trait are filled in black. What is the chance that a son of the third-generation female indicated by the arrow will be color blind if the father is not color blind? If he is color blind?arrow_forwardPedigree analysis is a fundamental tool for investigating whether or not a trait is following a Mendelian pattern of inheritance. It can also be used to help identify individuals within a family who may be at risk for the trait. Adam and Sarah, a young couple of Eastern European Jewish ancestry, went to a genetic counselor because they were planning a family and wanted to know what their chances were for having a child with a genetic condition. The genetic counselor took a detailed family history from both of them and discovered several traits in their respective families. Sarahs maternal family history is suggestive of an autosomal dominant pattern of cancer predisposition to breast and ovarian cancer because of the young ages at which her mother and grandmother were diagnosed with their cancers. If a mutant allele that predisposed to breast and ovarian cancer was inherited in Sarahs family, she, her sister, and any of her own future children could be at risk for inheriting this mutation. The counselor told her that genetic testing is available that may help determine if this mutant allele is present in her family members. Adams paternal family history has a very strong pattern of early onset heart disease. An autosomal dominant condition known as familial hypercholesterolemia may be responsible for the large number of deaths from heart disease. As with hereditary breast and ovarian cancer, genetic testing is available to see if Adam carries the mutant allele. Testing will give the couple more information about the chances that their children could inherit this mutation. Adam had a first cousin who died from Tay-Sachs disease (TSD), a fatal autosomal recessive condition most commonly found in people of Eastern European Jewish descent. Because TSD is a recessively inherited disorder, both of his cousins parents must have been heterozygous carriers of the mutant allele. If that is the case, Adams father could be a carrier as well. If Adams father carries the mutant TSD allele, it is possible that Adam inherited this mutation. Because Sarah is also of Eastern European Jewish ancestry, she could also be a carrier of the gene, even though no one in her family has been affected with TSD. If Adam and Sarah are both carriers, each of their children would have a 25% chance of being afflicted with TSD. A simple blood test performed on both Sarah and Adam could determine whether they are carriers of this mutation. Would you decide to have a child if the test results said that you carry the mutation for breast and ovarian cancer? The heart disease mutation? The TSD mutation? The heart disease and the mutant alleles?arrow_forwardPedigree analysis is a fundamental tool for investigating whether or not a trait is following a Mendelian pattern of inheritance. It can also be used to help identify individuals within a family who may be at risk for the trait. Adam and Sarah, a young couple of Eastern European Jewish ancestry, went to a genetic counselor because they were planning a family and wanted to know what their chances were for having a child with a genetic condition. The genetic counselor took a detailed family history from both of them and discovered several traits in their respective families. Sarahs maternal family history is suggestive of an autosomal dominant pattern of cancer predisposition to breast and ovarian cancer because of the young ages at which her mother and grandmother were diagnosed with their cancers. If a mutant allele that predisposed to breast and ovarian cancer was inherited in Sarahs family, she, her sister, and any of her own future children could be at risk for inheriting this mutation. The counselor told her that genetic testing is available that may help determine if this mutant allele is present in her family members. Adams paternal family history has a very strong pattern of early onset heart disease. An autosomal dominant condition known as familial hypercholesterolemia may be responsible for the large number of deaths from heart disease. As with hereditary breast and ovarian cancer, genetic testing is available to see if Adam carries the mutant allele. Testing will give the couple more information about the chances that their children could inherit this mutation. Adam had a first cousin who died from Tay-Sachs disease (TSD), a fatal autosomal recessive condition most commonly found in people of Eastern European Jewish descent. Because TSD is a recessively inherited disorder, both of his cousins parents must have been heterozygous carriers of the mutant allele. If that is the case, Adams father could be a carrier as well. If Adams father carries the mutant TSD allele, it is possible that Adam inherited this mutation. Because Sarah is also of Eastern European Jewish ancestry, she could also be a carrier of the gene, even though no one in her family has been affected with TSD. If Adam and Sarah are both carriers, each of their children would have a 25% chance of being afflicted with TSD. A simple blood test performed on both Sarah and Adam could determine whether they are carriers of this mutation. Would you want to know the results of the cancer, heart disease, and TSD tests if you were Sarah and Adam? Is it their responsibility as potential parents to gather this type of information before they decide to have a child?arrow_forward
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- Using the pedigree chart attached: Above is a pedigree for colorblindness. Based on the pedigree, is the disease dominant or recessive and is it sex-linked or autosomal? Why? Furthermore, what is the probability that 18 on this chart is affected but the condition, and what is the probability that 18 is a carrier? Why? Are the probability of being a carrier and an affected individual different? Why?arrow_forwardThis pedigree traces the inheritance of a trait in humans. Based on this pedigree, is the allele for this disease dominant or recessive? Is it sex-linked? Explain. What genotypes are most probable for the individuals labeled 4, 7, and 10?arrow_forwardPhenylketonuria (PKU) is a disease that results from a recessive gene.Suppose that two unaffected parents produce a child with PKU. a. What is the probability that a sperm from the father will contain the PKU allele?b. What is the probability that an egg from the mother will contain the PKU allele?c. What is the probability that their next child will have PKU?d. What is the probability that their next child will be heterozygous for the PKU gene?arrow_forward
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