Concept explainers
a.
To determine: The evidence in the pedigree charts that deterimine the deficicnecy genes are linked.
Introduction. The genes are the sequence of
b.
To determine: The evidence of crossing over in the genes if the genes are linked in the population.
Introduction. The law of independent assortment was given in a dihybrid cross which is the cross between the alleles of two pairs of contrasting characters. The alleles produced by each character are independent to combine with the alleles of the other character.
c.
To determine: The genotypes of the individuals in the family pedigree chart.
Introduction. The genotype is the genetic constitution of the organism while the
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Introduction to Genetic Analysis
- A rare blinding disease that has a relation to dengenerative factors is partially penetrant. In the following pedigrees for two families, the affected symptomatic individuals (black circles and squares) have been diagnosed with this disease due to the mutation in mitochondrial DNA m.14484T>C. If III.4 is homoplasmic for m.14484T>C in hair, blood, urine and other tissues examined. What will occur with IV.7 then?arrow_forwardIn mice, the autosomal locus coding for the β-globinchain of hemoglobin is 1 m.u. from the albino locus. Assume for the moment that the same is true in humans. The disease sickle-cell anemia is the result ofhomozygosity for a particular mutation in theβ-globin gene.a. A son is born to an albino man and a woman withsickle-cell anemia. What kinds of gametes will theson form, and in what proportions?b. A daughter is born to a normal man and a womanwho has both albinism and sickle-cell anemia.What kinds of gametes will the daughter form,and in what proportions?c. If the son in part (a) grows up and marries thedaughter in part (b), what is the probability that achild of theirs will be an albino with sickle-cellanemia?arrow_forwardSalim and Sara are contemplating having children, but Salim’s brother has galactosemia and Sara’s great-grandmother also had galactosemia. Sara has a sister who has three children, none of whom is affected.a. Construct a genetic pedigree for this family showing the possible genotype of each member.b. What is the probability that Salim and Sara’s first child will have galactosemia? Explain your calculations.arrow_forward
- The pedigree here shows the inheritance of a human disease knownas familial hypercholesterolemia. This disorder is characterized by an elevated level of serumcholesterol in the blood. Though relatively rare, this geneticabnormality can be a contributing factor to heart attacks. At themolecular level, this disease is caused by a defective gene thatencodes a protein called low-density lipoprotein receptor (LDLR).In the bloodstream, serum cholesterol is bound to a carrier proteinknown as low-density lipoprotein (LDL). LDL binds to LDLR,which enables cells to absorb cholesterol. When LDLR is defective,it becomes more difficult for the cells to absorb cholesterol. Thisexplains why the blood level of cholesterol remains high. Basedon the pedigree, what is the most likely pattern of inheritance ofthis disorder?arrow_forwardGalactosemia is a recessive human disease that istreatable by restricting lactose and glucose in the diet.Susan Smithers and her husband are both heterozygous for the galactosemia gene.a. Susan is pregnant with twins. If she hasfraternal (nonidentical) twins, what is theprobability both of the twins will be girls whohave galactosemia?b. If the twins are identical, what is the probabilitythat both will be girls and have galactosemia?For parts (c–g), assume that none of the children isa twin.c. If Susan and her husband have four children, whatis the probability that none of the four will havegalactosemia?d. If the couple has four children, what is the probability that at least one child will have galactosemia?e. If the couple has four children, what is the probability that the first two will have galactosemia andthe second two will not?f. If the couple has three children, what is the probability that two of the children will have galactosemia and one will not, regardless of order?g. If…arrow_forwardHemophilia A is caused by a sex-linked recessive gene in human and in dogs. a. What proportions (and sexes), among their offspring will be hemophiliacs if a hemophilic male is mated to a homozygous nonhemophilic female?b. If a daughter produced by the mating in (a) is mated to a normal male, what proportions and (sexes) will be hemophilic among their offspring?arrow_forward
- Consider two hypothetical recessive autosomal genes a and b, where a heterozygote is testcrossed to a double- homozygous mutant. Predict the phenotypic ratios under the following conditions: (a) a and b are located on separate autosomes. (b) a and b are linked on the same autosome but are so far apart that a crossover always occurs between them. (c) a and b are linked on the same autosome but are so close together that a crossover almost never occurs.arrow_forwarda. On the basis of this pedigree, what is the most likely mode of inheritance for the disease? Explain your reasoning. b. Based your answer to part a, give the most likely genotypes for all family members in the pedigree.arrow_forwardThe accompanying pedigree shows the pattern of transmission of two rare human phenotypes: cataract andpituitary dwarfism. Family members with cataract areshown with a solid left half of the symbol; those withpituitary dwarfism are indicated by a solid right halfa. What is the most likely mode of inheritance of each ofthese phenotypes? Explain.b. List the genotypes of all members in generation III asfar as possible.c. If a hypothetical mating took place between IV-1 andIV-5, what is the probability of the first child’s being adwarf with cataracts? A phenotypically normal child?(Problem 48 is adapted from J. Kuspira and R. Bhambhani, Compendium of Problems in Genetics. Copyright1994 by Wm. C. Brown.)(Picture added)arrow_forward
- Adult hemoglobin is a multimeric protein with fourpolypeptides, two of which are α-globin and two ofwhich are β-globin.a. How many genes are needed to define the structureof the hemoglobin protein?b. If a person is heterozygous for wild-type allelesand alleles that would yield amino acid substitutionvariants for both α-globin and β-globin, how manydifferent kinds of hemoglobin protein would befound in the person’s red blood cells and in whatproportion? Assume all alleles are expressed at thesame level.arrow_forwardIn the following pedigree, filled circles or squares indicate affected individuals. Write your answers based on this. a. Does the following pedigree suggest mitochondrial inheritance? Why or why not? b. What other mode(s) of inheritance is (are) consistent with these data? c. How could you distinguish between mitochondrial inheritance and any other possibility that is consistent with the data?arrow_forwardTake the example of B-thalassemia, an autosomal recessive genetic disease that particularly affects people from around the Mediterranean. This disease is associated with an anomaly of hemoglobin, a protein essential for the transport of oxygen, which is composed of four chains: two alpha (a) and two beta (B). In case of B-thalassemia, the ẞ chains are produced in insufficient or no quantity in an individual homozygous recessive resulting in insufficient production of overall hemoglobin leading to anemia and other physiological challenges. The gene that controls the synthesis of the ẞ chains is located on chromosome 11. Here is part of the coding portion of this gene (which controls a total of 146 amino acids and of which you only see the portion 36 to 41) and one of the targeted mutations: 1. Give the sequence of amino acids from the template and mutated strands. 2. What type of point mutation is it? 3. Using the principles of the theory of evolution, explain briefly and generally why…arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning