Exam 22: Developmental Genetics and Immunogenetics

Which specific group of genes specifies the identities of individual body segments?

The proteins Dorsal and Bicoid both act as morphogens in Drosophila embryogenesis. However, the establishment of the concentration gradients of each protein differs. Which of the following statements CORRECTLY describes this difference?

Which of the following statements about Hox genes is INCORRECT?

What is apoptosis?

During development, cells can respond to the presence of hormones and other signals with changes in gene expression that can bring about cell differentiation. In most cases, the differentiated state needs to be maintained through subsequent cell divisions and long after the inducing signal has disappeared. Describe a mechanism that can maintain the differentiated state after the inducing signal has disappeared.

Distinguish between the genetic mechanisms used to generate antibody diversity within a person's immune system and those used to generate MHC antigen diversity between different individuals.

How do lymphocytes violate the general principle that all cells in an organism contain the same set of genetic information?

Which of the following statements about homeotic genes is INCORRECT?

Use the following to answer questions In the nematode worm C. elegans loss-of-function ced-3 mutations lead to more cells than normal due to a defect in apoptosis. Loss-of-function mutations in ced-9 cause embryonic lethality due to ectopic cell deaths. The phenotype of ced-9; ced-3 double mutants is the same as ced-3 single mutants; that is, there are more cells than normal due to a defect in apoptosis. Genes ced-3 and ced-9 are known to act in the same genetic pathway. -Which of the following pathways is consistent with the genetic data?

Use the following to answer questions The diagram below illustrates the normal expression of three different groups of genes (A, B, and C) within four different whorls of a developing flower. Normally, whorl 1 produces sepals, whorl 2 produces petals, whorl 3 produces stamens, and whorl 4 produces carpels. Furthermore, expression of class A genes inhibits class C genes, and expression of class C inhibits class A. -What kind of mutation would produce carpels in whorls 1 and 4 and stamens in whorls 2 and 3?

The following diagram describes the genetic regulation of flower development in angiosperms. In each box, write the class of gene, and below write the flower structures determined by those gene(s).

The primary function of differentiated B lymphocytes within the vertebrate immune system is to produce:

What is apoptosis? Describe the important roles that apoptosis plays during development of an organism. Provide specific evidence that apoptosis is important to normal development.

Which of the following characteristics of vaccines are required in order for them to be effective in immunization? (Select all that apply.)

What have the cloning experiments in plants and animals confirmed with regard to developmental processes?

(a) In what sense does each person's immune system become adapted to that person's environment and to the set of antigens to which that person is exposed? (b) Explain in terms of the clonal selection theory how a person's immune system responds to and comes to be "adapted" to the person's environment and personal exposure to antigens.

Use the following to answer questions In the late 1940s Edward Lewis discovered mutations in the Antennapedia gene that lead to legs developing on the head of a fly instead of antenna. These mutations are dominant and lead to ectopic expression of the Antennapedia gene. -Based on these data, how would you expect the gene to be expressed in the mutant? (Select all that apply.)

Use the following to answer questions The diagram below illustrates the normal expression of three different groups of genes (A, B, and C) within four different whorls of a developing flower. Normally, whorl 1 produces sepals, whorl 2 produces petals, whorl 3 produces stamens, and whorl 4 produces carpels. Furthermore, expression of class A genes inhibits class C genes, and expression of class C inhibits class A. -What kind of mutation would produce sepals in all four whorls?

Xenotransplantation involves transplanting tissues or organs from one species to another. Some medical researchers are exploring the possibility of transplanting pig organs into humans to address the worldwide human organ donor shortage. What strategies might help with the success of such transplantations? (Select all that apply.)

The Bicoid protein in fruit flies specifies anterior development. In the absence of Bicoid protein in an egg, the embryo will develop two tails. The bcd^- mutation is recessive and exhibits a maternal effect. Which of the following CORRECTLY describes the embryos produced from a cross between a bcd⁺/ bcd^- male and a bcd^-/bcd^- female?