Concept explainers
A.
To determine: The pedigree for the given condition.
Introduction: Galactosemia is a limited genetic
B.
To determine: The probability that this child will have galactosemia.
Introduction: Galactosemia is an autosomal recessive disease. An autosomal illness is a condition that does not depends on the sex chromosomes. If two people who possess galactosemia have children, all of them will have galactosemia.
C.
To determine: If the first child has galactosemia, the probability that a second child will also be having the same condition.
Introduction: An autosomal recessive disorder indicates both copies of the gene in every cell need to hold the mutation for a person to exhibit indications. The parents of an affected person typically bear one copy of the abnormal gene, though they do not show symptoms of galactosemia.
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Introduction to Genetic Analysis
- 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?arrow_forwardGlucose-6-phosphate dehydrogenase (G6PD) deficiency is a disorder that affects the normal function of red blood cells and can eventually lead to anemia. The trait is controlled by a recessive allele found on the X chromosome. An affected son was born to a man and woman who were unaffected. The woman’s mother was affected while the father was normal. a. Indicate the gene notation. b. Give the genotypes of the affected boy’s parents. c. Derive the genotypic and phenotypic ratios for the offspring. Show and label your solutions properly. d. What is the probability that they will have a phenotypically normal daughter as their first child? e. If they have four children, what is the probability that three out of their four children will be normal and one will be affected?arrow_forwardA young couple went to see a genetic counselor because each had a sibling affected with cystic fibrosis. (Cystic fibrosis is a recessive disease, and neither member of the couple nor any of their four parents is affected.) a. What is the probability that the female of this couple is a carrier? b. What are the chances that their child will be affected with cystic fibrosis? c. What is the probability that their child will be a carrier of the cystic fibrosis mutation?arrow_forward
- Galactosemia 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_forwardKate and her husband are both heterozygous for galactosemia gene. If Kate and her husband have four children, how many of their children are likely to have galactosemia?arrow_forwardPhenylketonuria (PKU) is a disorder caused by a recessive allele. Two carrier individuals have progeny. Answer the following questions in order and show solutions whenever relevant. a. Indicate the gene notation.b. Derive the expected genotypic and phenotypic ratios.c. If they have a normal child, what is the probability that he or she will be heterozygous?d. If they have three children, what is the probability of having 2 affected children and one normalchild?arrow_forward
- Sickle cell anemia is an inherited red blood cell disorder in which there are not enough healthy red blood cells to carry oxygen throughout the body. The allele that causes sickle-cell anemia is autosomal recessive (s), and the dominant allele can be represented by S. How many offspring will be affected by the disorder if the mother is a carrier, and the father appears to be normal? (Include the gender) a. b. How many will become carriers? (include the gender) A- 三三三 四 四 II !!arrow_forwardHemophilia is a disease inherited as a X-linked recessive trait while pattern baldness is controlled by an autosomal gene that is dominant in males and recessive in females. A hemophilic man who is also homozygous for baldness has children with a woman who carries normal genes for both traits. What is the probability that any of their child will be: a. Hemophilic, normal-haired male b. Hemophilic, bald male c Female with normal blood clotting and bald Note: Show how you derived your answers.arrow_forwardA man is brachydactylous (very short fingers; rare autosomal dominant), and his wife is not. Both can taste the chemical phenylthiocarbamide (autosomal dominant; common allele), but their mothers could not.a. Give the genotypes of the couple.If the genes assort independently and the couple has four children, what is the probability ofb. all of them being brachydactylous?c. none being brachydactylous?d. all of them being tasters?e. all of them being nontasters?f. all of them being brachydactylous tasters?g. none being brachydactylous tasters?h. at least one being a brachydactylous taster?arrow_forward
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a disorder that affects the normal function of red blood cells and can eventually lead to anemia. The trait is controlled by a recessive allele found on 4. the X chromosome. An affected son was born to a man and woman who were unaffected. The woman's mother was affected while the father was normal. a. Indicate the gene notation. b. Give the genotypes of the affected boy's parents. Derive the genotypic and phenotypic ratios for the offspring. Show and label your solutions properly. What is the probability that they will have a phenotypically normal daughter as their first child? C. d.arrow_forward15. The following pedigree shows inheritance of Huntington's disease, a fatal genetic disorder that causes neurodegeneration. Since signs and symptoms usually do not appear until adulthood, many who are carriers may not realize their risk of passing on the disease-causing allele. The following pedigree represents a family in which some people are affected by Huntington's disease. Reeessive Trit er btmnt be Mec yplicalty Hinheteearrow_forwardPompe disease is a glycogen storage disorder caused by a lack of a-glucosidase, the enzyme that converts glycogen to glucose in the muscles. Babies born with this disorder die by the age of two. Pompe disease is a genetic disorder caused by the presence of two recessive autosomal alleles. A man and a woman heterozygous for the condition have two female unaffected children. Determine the probability, expressed as a whole number percentage, of a third baby being born a male with Pompe disease. Your answer must include the use of a Punnett square as well as a legend indicating the allele symbols used.arrow_forward
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