Exam 14: Mendel and the Gene Idea

Which of the following is an example of polygenic inheritance?

Use the following pedigree shown below for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. -The affected woman in generation IV is thinking about her future and asks her oncologist (cancer specialist)whether she can know whether any or all of her children will have a high risk of the same cancer. The doctor would be expected to advise which of the following? I. genetic counselling II. prenatal diagnosis when/if she becomes pregnant III. testing to see whether she has the allele IV. testing to see whether her future spouse or partner has the allele

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

Refer to the following information to answer the questions below. Humanoids on the newly explored planet Brin (in a hypothetical galaxy in ~50 years from the present) have a gene structure similar to our own, but many very different plants and animals. -One species of a small birdlike animal has an extremely variable tail length, which is a highly polymorphic trait. Geneticists have come to realize that there are eight separate genes for tail length per haploid genome, with each gene having two alleles. One allele for each gene (a, b, and so on)increases the length by 1 cm, whereas the other allele (a₂, b₂, and so on)increases it by 0.5 cm. One bird was analyzed and found to have the following genotype: a₁a₁b₂b₂c₁c₂d₁d₂e₂e₂f₁f₂g₁g₁h₁h₂ What is the length of its tail?

Visitors at Algonquin Park in Northern Ontario may miss out on the brilliant red colouration of Acer sacchrum in autumn because

Use the following description and figure to answer the questions below. In a particular plant, leaf colour is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F₁ offspring is allowed to self-pollinate. The predicted outcome of the F₂ is diagrammed in the Punnett square shown in Figure 14.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. -Which of the plants will be true-breeding?

Which of the following provides an example of epistasis?

Use the following information to answer the questions below. Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F₁ individuals have red, axial flowers. The genes for flower colour and location assort independently. -Among the F₂ offspring, what is the probability of plants with white axial flowers?

The following questions refer to the pedigree chart in the figure below for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. -What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible genotype for the mother?

Use the following information to answer the questions below. Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. -These results indicate which of the following?

An individual that has two different alleles for the same trait is said to be

An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable genetically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient?

Black fur in mice (B)is dominant to brown fur (b). Short tails (T)are dominant to long ?tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?

Use the following information to answer the questions below. Tay-Sachs disease is an inherited genetic disorder in which the gene sequence codes for an enzyme involved in lipid metabolism. Accumulation of lipids in the brain leads to seizures, blindness, loss of neural function, and early death. People can be carriers of this disease and only homozygotic offspring will die from this disorder. -This is an example of

If the environmental parameters, such as temperature, humidity, atmosphere, sunlight, and so on, are mostly Earthlike, which of the following do you expect of its types of leaves, stems, and flowers?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible partial genotype for the son?

Which of the following calculations requires that you utilize the addition rule?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible phenotype for the father?

Use the information given here to answer the following questions. Feather colour in budgies is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. -A blue budgie is crossed with a white budgie. Which of the following results is not possible?