Concept explainers
Situs inversus is a congenital condition in which the major visceral organs are reversed from their nor-mal positions. Investigations into the genetics of this abnormality revealed that individuals with at least one dominant allele (SI) of an autosomal gene are normal but, surprisingly, of individuals that are homozygous for a recessive allele (si),
a. What genotypes and
b. What genotypes and phenotypes are expected in prog-eny from a cross of two SI si individuals?
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
Genetic Analysis: An Integrated Approach (3rd Edition)
- 1. A) Apply the concept of sex linkage to explain why color blindness is more prevalent in men than in women. B) Mary is concerned that she may be a carrier for hemophilia, a sex-linked condition located on the X chromosome. Mary is married to John, who doesn't have hemophilia. Assuming Mary is a carrier, what are the genotype ratios expected for Mary and John's kids (specify for boys and for girls)? C) Mary and John have 2 boys, none of them has hemophilia. Can we use this fact as proof that Mary does not carry the allele for hemophilia? Explain your argument.arrow_forwarda. A certain form of sickle cell anemia is caused by an autosomal recessive allele. Assume that the mutation rate is 1 x 10-5 and that persons having this condition can only produce about 80% of the normal offspring. i. At equilibrium between mutation and selection, what will the frequency of the allele for sickle cell anemia be? Show your calculation.arrow_forwardy 301 Amelogenesis imperfecta is X-linked dominant. Affected XY individuals have extremely thin enamel on the teeth while XX carriers have grooved teeth from uneven deposition of enamel. If an unaffected XY individual were to produce children with a XX carrier partner, a. what would be the expected chance of a XY child being affected with the disease? b. what would be the expected chance of a XY child being affected with the disease?arrow_forward
- Many genetic disorders exhibit locus heterogeneity. Define andgive two examples of locus heterogeneity. How does locus heterogeneityconfound a pedigree analysis?arrow_forwardAnhidrotic ectodermal dysplasia is an X-linked recessive disorder in humans characterized by small teeth, no sweat glands, and sparse body hair. This trait is usually seen in men, but women who are heterozygous carriers of the trait often have irregular patches of skin with few or no sweat glands (see the illustration below). a. Explain why women who are heterozygous carriers of a recessive gene for anhidrotic ectodermal dysplasia have irregular patches of skin lacking sweat glands. b. Why does the distribution of the patches of skin lacking sweat glands differ among the females depicted in the illustration, even between the identical twins?arrow_forwardExplain why disease alleles for cystic fibrosis (CF)are recessive to the normal alleles (CF+), yet thedisease alleles responsible for Huntington disease(HD) are dominant to the normal alleles (HD+).arrow_forward
- Examine the karyotypes of Jacob and PAtau syndromes. List the similarities and differences between these two syndromes. which is more severe?arrow_forwardColor blindness in humans is controlled by an X-linked completely recessive allele (Xc), while breast cancer is controlled by an autosomal completely dominant allele, B. A color blind male, who is a heterozygote carrier for breast cancer has three children/n with a normal eyed female (whose mother was color blind), who is homozygote recessive for the breast cancer allele. What is the probability that out of three children, 2 will be color blind males, and not show breast cancer, and one will be a color blind female, who shows breast cancer?arrow_forward3) Achondroplasia is a common form of hereditary dwarfism that causes very short limbs, stubby hands, and an enlarged forehead. Below are three pedigrees depicting families with this specific type of dwarfism. A. What is the most likely mode of inheritance?arrow_forward
- Consider an autosomal recessive disease in which an individual must inherit two recessive alleles to display the disease phenotype. What is the probability that a woman who is a heterozygous for the trait and a man who is homozygous for the dominant allele will produce an offspring with the autosomal recessive phenotype? Assume no new mutations occur. Select one 1.) 100% 2.)25% 3.) 0% 4.)50% 5.) More information is neededarrow_forwarda) Identify and describe 5 different types of genetic inheritance.(b) In humans, glucose-6-phosphate dehydrogenase deficiency is a recessive X-linkedtrait. Describe the inheritance of this disease, including an example of the possibleoutcomes of:(i) An affected mother and an unaffected father having children. (ii) An affected father and a homozygous unaffected mother having childrenarrow_forward1a) Explain one autosomal pattern of Mendelian inheritance. 1b) Describe one example of a disorder caused by this pattern on inheritance.arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education