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)
- While studying of the family tree with history of hypertrichosis (hyper hirsutism of the ear) this sign was founded only in the men and it was inherited from father to the son. Define the type of hypertrichosis inheritance? Select one: a. Y-linked b. Autosomal-recessive O c. Autosomal-dominant d. Recessive, X-linked e. Dominant, X-linkedarrow_forward1. In the pedigree below, Use "A" for the allele associated with the dominant phenotype, and lowercase "a" for the allele associated with the recessive phenotype. Determine what is the most likely mode of inheritance of this disease (whether it is inherited as the result of an autosomal dominant or autosomal recessive trait). Write the most probable genotype for each individual based on the mode of inheritance you have determined. Show how all the partners are crossed and the expected offspring produced (You may use Punnett Square) 1 dró || IVarrow_forwardPls answer the very last question. “ suppose that lll-2 and lll-5 were to have a child. What is the probability that their first child will be have the disorder?”arrow_forward
- 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_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_forwardvarrow_forward
- a. 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_forwardExamine the karyotypes of Jacob and PAtau syndromes. List the similarities and differences between these two syndromes. which is more severe?arrow_forward
- Anhidrotic 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_forward12. A. B. C. A certain type of migraine headache (M) is dominant to no migraines (m). What is the genotype of a man who has migraine headaches if his father did not have them? What is the genotype of a man who has migraine headaches if his mother did not have them? If a woman without migraines marries a man who is heterozygous for migraines, what would you expect for the genotypes and phenotypes of their children? If two people who are heterozygous for migraines marry and have children, what would you expect for the genotypes and phenotypes of the children.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
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning