Concept explainers
Galactosemia is an autosomal recessive disorder caused by the inability to
a. Draw a pedigree that includes Amanda, Brice, and their siblings and parents. Identify the genotype of each person, using G and g to represent the dominant and recessive alleles, respectively.
b. What is the probability that Amanda is a carrier of the allele for galactosemia? What is the probability that Brice is a carrier? Explain your reasoning for each answer.
c. What is the probability that the first child of Amanda and Brice will have galactosemia? Show your work.
d. If the first child has galactosemia, what is the probability that the second child will have galactosemia? Explain the reasoning for your answer.
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
Genetic Analysis: An Integrated Approach (2nd Edition)
- parents, but her brother Alonzo has Galactosemia. Brice has a similar family history. He and his parents are healthy, but his sister Brianna has galactose, a component of the lactose found in mammalian milk. Galactosemia can be galactosemia. Amanda and Brice are planning on marrying and starting a family and partially managed by eliminating dietary intake of lactose and galactose. Amanda is Galactosemia is an autosomal recessive disorder caused by the inability to metabolize seek genetic counseling. Based on the information provided, complete the following: healthy, as are her A piaw a pedigree that includes Amanda, Brice, their siblings, and parents. Identily the genotypes of each person using G and a to represent the dominant and recessive alleles. B What is the probability that Amanda is a carrier of the allele for galactosemia? Same question for Brice? Explain. non bard bito te over ovodaarrow_forwardAchondroplasia is an autosomal dominant disorder characterized by disproportionate short stature: the legs and arms of people with achondroplasia are short compared with the head and trunk. The disorder is due to a base substitution in the gene, located on the short arm of chromosome 4, that encodes fibroblast growth factor receptor 3 (FGFR3). Although achondroplasia is clearly inherited as an autosomal dominant trait, more than 80% of the people who have achondroplasia are born to parents with normal stature. This high percentage indicates that most cases are caused by newly arising mutations; these cases (not inherited from an affected parent) are referred to as sporadic. Studies have demonstrated that sporadic cases of achondroplasia are almost always caused by mutations inherited from the father (paternal mutations). In addition, the occurrence of achondroplasia is higher among the children of older fathers; approximately 50% of children with achondroplasia are born to fathers…arrow_forwardPhenylketonuria is one of the most common recessive genetic disorders in humans. Infants with PKU are missing an enzyme called phenylalanine hydroxylase, needed to break down an amino acid called phenylalanine. If a strict diet that minimizes the amount of phenylalanine in the diet is not followed, a severe nervous disorder may result. If two heterozygous parents have a child, hah is the possible genotype and phenotype for this individual?arrow_forward
- Sickle cell anemia is inherited as an autosomal recessive condition. It also exhibits incomplete dominance in that the heterozygous genotype displays a mild form of the disease known as sickle cell trait while individuals with the homozygous recessive genotype have a severe form of SCA. A man who has severe sickle cell anemia marries a woman who suffers from a mild trait. What is the probabilitu they will have a child with severe SCA?What is the probability they will have a child with mild SCA? What is the probability they will have a normal child? Show ALL work using punnett squares.arrow_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_forwardTuberous Sclerosis (TS) is an autosomal dominant genetic disease characterized by seizures, mental retardation, autism, and benign tumors of the brain, heart, skin, and kidneys. The kidney tumors can also be malignant. This disease exhibits a wide range of severity, and only about 1/3 of the cases are inherited. Two different genes have been tightly linked to the disease in families where it is inherited. The remaining 2/3 appear to be due to mutations in one of the 2 genes as well. Overall it appears that 1/2 are caused by mutations in TSC1 and the other half by mutations in TSC2. A rat model for hereditary renal carcinoma (kidney cancer) has been found. Southern and Northern blot analysis of the TSC1 and TSC2 gene revealed no differences between these rats and normal rats. Not all the rats in the strain would get cancer but a significant proportion did and those were selected for and used in experiments. 1. a) What was detected by the Southern blots? (look this up, make your…arrow_forward
- Olivia S. was born with a rare recessive disorder called tyrosinemia.The next day, Olivia M. was born in a neighboringstate with the same disorder. Tyrosinemia is causedby the lack of an enzyme in the degradation pathway of the aminoacid tyrosine. Accumulation of metabolic intermediates causesprogressive liver dysfunction and kidney problems. One-year-oldOlivia S. is healthy and has no symptoms of the disorder. At thesame age, Olivia M. developed total liver failure. Olivia S. was bornin a state where newborns are tested for tyrosinemia, but Olivia M.was born in a state where newborns are not tested for this disorder.A week after diagnosis, Olivia S. was placed on a low-tyrosinediet and prescribed a drug to block the accumulation of metabolicintermediates. Olivia M. was not diagnosed until she was in liverfailure; she then was placed on a low-tyrosine diet, was prescribedmedication, and underwent a liver transplant. She faces a lifetimeof antirejection drug therapy and may require a…arrow_forwardnbdayarrow_forwardYour brother has an autosomal recessive disorder, while you are unaffected. Neither one of your parents is affected. Explain how this is possible.arrow_forward
- Alberta is phenotypically normal, but her brother (Rodrigo) has albinism, which is caused by an autosomal recessive mutation. The probability that Alberta is a carrier (i.e., heterozygous for albinism) is [express your answer as a fraction]arrow_forwardBelow is a pedigree chart for a family that has a history of Alkaptonuria. Individuals infected with this condition can have darkened skin, brown urine, and can suffer from joint damage and other complications. Given this pedigree answer the following questions. Given the data in the pedigree chart is this genetic condition autosomal dominant or autosomal recessive? What are the genotypes for #1, #2, and #3? If either of the 4th generation "aa" females were to mate with a homozygous dominant male would any of their offspring illustrate the phenotype? Why or why not?arrow_forwardWhat is the genetic basis and phenotype for each of the following disorders (use proper genetic notation)? a. Edwards syndrome b. Patau syndrome c. Klinefelter syndrome d. Down syndromearrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage Learning