9. The Pitx1 protein has important functions in various tissues during stickleback development. The complete absence of the Pitx1 protein from all tissues is lethal to the organism. However, as shown in the film, Pitx1 protein can be absent in the pelvis alone, and the fish survives. The absence of Pitx1 in the pelvis confers a unique phenotype. Mark the fish below that lacks Pitx1 expression in the pelvis. a b

9. The Pitx1 protein has important functions in various tissues during stickleback development. The complete absence of the Pitx1 protein from all tissues is lethal to the organism. However, as shown in the film, Pitx1 protein can be absent in the pelvis alone, and the fish survives. The absence of Pitx1 in the pelvis confers a unique phenotype. Mark the fish below that lacks Pitx1 expression in the pelvis. a b

Biology: The Unity and Diversity of Life (MindTap Course List)

14th Edition

ISBN:9781305073951

Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr

Publisher:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr

Chapter10: Control Of Gene Expression

Section: Chapter Questions

Problem 4CT: The photos above show flowers from Arabidopsis plants. One plant is wild-type (unmutated); the other...

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3. Figure 2 illustrates how Pitx1 transcription is regulated in different tissues. The center image is that of a stickleback embryo. The drawings in the surrounding boxes show the Pitx1 gene region and activator proteins present in the jaw, pelvis, eye, or pituitary tissues. a. List all the tissues shown in Figure 2 that express the Pitx1 gene. b. If a fish does not produce activator 1 proteins because of a mutation in the gene that encodes those proteins, Pitx1 will be expressed in which of the following tissues? c. If a fish does not produce activator 3 proteins, Pitx1 will be expressed in which of the following tissues? d. A fish inherits a mutation in the Pitx1 coding region. This is a nonsense mutation that introduces a premature stop codon, resulting in a nonfunctional protein. Where would you expect Pitx1 to be expressed in this scenario?
LO: Explain how mutations in regulatory regions of genes differ from mutations in coding region The presence or absence of pelvic spines in the stickleback fish is controlled by whether the Pitx1 gene is expressed in the pelvic tissue. The Figure below shows how Pitx1 transcription is regulated in different tissues. The center image is that of a stickleback embryo. The drawings in the surrounding boxes show the Pitx1 gene region and activator proteins present in the jaw, pelvis, eye, or pituitary tissues. While the diagram only shows one activator in one tissue, many activators are present in a particular tissue at any one time. Activator molecules with specific shading can bind to switches with the same shading. 3a) Based on the diagram, in which tissues will the PitX1 gene be expressed? 3b) Assume a fish inherits a deletion mutation in the pituitary switch/enhancer sequence. You isolate DNA from jaw, pelvic, eye, and pituitary tissues. In the DNA of which tissue(s) would…
6. Suppose a particular gene is required for early development and also later for development of a particulartissue, such as the adult nervous system. By generating a homozygous mutant clone in that tissue of a heterozygote, researchers can circumvent the lethalitythat would result if the entire animal is homozygousfor a loss-of-function mutation in that gene.A technique called MARCM (Mosaic Analysiswith a Repressible Cell Marker) was developed to enable Drosophila geneticists to generate homozygousmutant cell clones that are marked by the presence of areporter protein such as GFP. Marker expression enables the investigator to observe clearly the mutantphenotype within a clone of mutant cells. This technique relies on a yeast protein called Gal80 that is anegative regulator of the Gal4 protein described previously in Solved Problem II. Gal80 binds to Gal4 andprevents it from activating transcription. The idea ofMARCM is that Gal4/UASG-driven GFP expression isblocked by Gal80 throughout…
Gene X is expressed in the developing brain, heart, andlungs of mice. Mutations that selectively affect gene Xfunction in these three tissues map to three differentregions (A, B, and C, respectively) 5′ of the X codingregion.a. Explain the nature of these mutations.b. Draw a map of the X locus consistent with the preceding information.c. How would you test the function of the A, B, and Cregions?
Pax6 is a gene that is involved in mammalian eye development. Mutations in this gene result in a lack of iris in humans, and mice that are homozygous for the mutation lack eyes completely. Mutations in the eyeless gene in the fruitfly Drosophila result in reduced eyes. Expressing Pax6 from mammals in other tissues of Drosophila during its embryonic development can result in an ectopic eye (e.g. an eye expressed in a different tissue type). An example of an ectopic eye on the antenna of Drosophila is shown below. Part A: The eye of humans, mouse, and fly are an example of the following (check all that apply) A. Structural analog B. Structural homolog C. Developmental homolog D. Genetic homolog Part B: Darwin's hypothesis of natural selection has two components: Species are not static but change through time Species are related, and not independent. In what ways does the human, mouse, and fly eye support or contradict one or both of the two components of…
1. How do muscle cells remain differentiated as muscle cells? 2. A mutation occurs in the Drosophila doublesex gene that prevents Tra from binding to the dsx RNA transcript. What would be the consequences of this mutation for Dsx protein expression in males? In females?
2. a. You want to create a genetic construct that will express GFP in Drosophila. In addition to the GFPcoding sequence, what DNA element(s) must youinclude in order to express this protein in flies if theconstruct were integrated into the Drosophila genome? Where should such DNA element(s) be located? How would you ensure that GFP is expressedonly in certain tissues of the fly, such as the wing?b. Suppose you insert the GFP coding region plus allof the DNA elements required by the answer to part(a)—except the enhancer—between inverted repeatsfound at the ends of a particular transposable element.Because all of the DNA sequences located betweenthese inverted repeats can move from place to placein the Drosophila genome, you can generate manydifferent fly strains, each with the construct integrated at a different genomic location. You now examine animals from each strain for GFPfluorescence. Animals from different strains showdifferent patterns: some glow green in the eyes,others in…
In comparison to experimental results from the genetic manipulation of an invertebrate model, what pathologic outcome(s) would suggest that multiple homologs of a disease gene are present in humans? a. Missing the essential gene homolog that is lethal in fruit flies is also lethal in human infants. b. Different homologs of the essential gene are each expressed in different human organs, and mutations in these duplicated genes cause organ-specific diseases. c. Different homologs of the essential gene are each expressed in different stages of early child development, and mutations in each of these duplicated genes cause different diseases. d. In humans, defects in different homologs of the essential gene cause different loss-of-function diseases due to subfunctionalization. e. The essential gene is lethal in fruit flies, but there is no disease phenotype exhibited in people.
1.Which of the following events is NOT involved in anteroposterior axis determination?* a. Dickkopf inhibits Xwnt8 at the posterior regionption 1 b. Cerberus inhibits BMP4 at the posterior region. c. Frizzled-related protein inhibits Xwnt8 at the anterior region d. Cerberus inhibits nodal-related protein at the anterior region 2. Which of the following statements BEST explains the dorsalizing function of the gurken gene?* a. The gurken ligands bind to torpedo receptors of follicles b. The gurken proteins inhibit pipe genes in the dorsal follicle cells. c. The gurken gene is activated at the dorsally located nucleus of the egg. d. The gurken mRNAs are synthesized at the dorsal portion of the egg cel
The figure below shows the domains of expression of various maternal and gap genes as well as the expression pattern of the even-skipped gene. knirps (kni) represses expression of eve stripes 3, 4, 6, and 7. Which stripe enhancer (stripe 3 or stripe 4) would you expect to have higher affinity binding sites for the Knirps protein. Explain your answer.
1. Using the data available Using the data available on Moodle describe the phenotype that you observe when each of these three genes is knocked down using RNAi. Remember to compare the worms on control RNAi plates with worms on each of the RNAi knockdown plates. In each case state how do these phenotypes relate to the function of the gene. describe the phenotype that you observe when each of these three genes is knocked down using RNAi. Remember to compare the worms on control RNAi plates with worms on each of the RNAi knockdown plates. In each case state how do these phenotypes relate to the function of the gene. 2. Describe further experiments that you could do that would confirm your findings.
Homeotic genes(A) encode transcription factors that control the expression ofgenes responsible for specific anatomical structures.(B) are found only in Drosophila and other arthropods.(C) are the only genes that contain the homeobox domain.(D) encode proteins that form anatomical structures in the fly.