A C. elegans (nematode) gene called par-1 helps todetermine the AP axis of the animal early in development. Scientists determined that par-1 is pleiotropic—it also has a later function in forming the vulva of theadult animal. How could researchers circumvent thelethality of par-1− mutants to observe the later function of the par-1 gene? (Hint: C. elegans larvae caneat bacteria expressing RNAi for any gene.)

A C. elegans (nematode) gene called par-1 helps todetermine the AP axis of the animal early in development. Scientists determined that par-1 is pleiotropic—it also has a later function in forming the vulva of theadult animal. How could researchers circumvent thelethality of par-1− mutants to observe the later function of the par-1 gene? (Hint: C. elegans larvae caneat bacteria expressing RNAi for any gene.)

Biology Today and Tomorrow without Physiology (MindTap Course List)

5th Edition

ISBN:9781305117396

Author:Cecie Starr, Christine Evers, Lisa Starr

Publisher:Cecie Starr, Christine Evers, Lisa Starr

Chapter6: Dna Structure And Function

Section: Chapter Questions

Problem 2CT

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The easily observed external structures in insects, such as different pairs of legs, antennae, and wings form from imaginal discs. a.) How is the identity of the different Drosophila imaginal discs established in the embryo—for example, how is it determined whether a disc will form a wing, a leg, or some other structure? b.) Dominant mutants in the gene Antennapedia result in fore legs forming in the location where antennae are expected. How does this mutant phenotype illustrate your response to Part a?
The eyes of Drosophila develop from imaginal discs, groups of cells set aside in the fly embryo that differentiate into the adult structures during the pupal stage. Despite their importance in nature, eyes are dispensable for fruitfly life in the laboratory. Devise a genetic screen to identify genes directing development of the fly eye. What complications might arise from genetic screens targeting an organ that differentiates late in development?
You have identified a Drosophila gene that is expressed exclusively in the odd-numbered "stripes" in the cellular blastoderm. Assuming that this gene is not redundant, what would be the most likely phenotype cause by a loss-of-function mutation in this gene? an embryo missing odd numbered segments an adult fly with a second pair of wings instead of halteres an embryo with two anterior ends an embryo missing even-numbered segments an embryo missing larval segments 3-10
In flies, the gap gene kruppel is expressed in a broad band in the middle of the embryo with giant expressed as its anterior border and knirps at its posterior border. How is the expression of kruppel limited to this band in the embryo? Describe the spatial regulation of the kruppel gene.
) Explain how and why dorsal/ventral polarity will be affected in fly Question 3 (1. embryos carrying the following mutations; also in each case darken in the area of the cells in the cross-sectional view of the fly embryo which are expected to express the paulie gene. D = dorsal; V = ventral. a) a mutation which results in the deletion of the cytoplasmic domain of the Cookie protein. b) A mutation which results in a constitutively active Bombe protein, i.e. the Bombe protein is always in an activated state. c) A mutation which causes the Pickle protein to be retained in the cytoplasm of the embryo.
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Another way to study the role of proteins (e.g., transcription factors) that function in development is to microinject the mRNA that encodes a protein, or the purified protein itself, into an oocyte or embryo, and then determine how this affects the subsequent development of the embryo, larva, and adult. For example, if Bicoid protein is injected into the posterior region of an oocyte, the resulting embryo will develop into a larva that has anterior structures at both ends. Based on your understanding of the function of each developmental gene, what would be the predicted phenotype if the following proteins or mRNAs were injected into normal oocytes? A. Nanos mRNA injected into the anterior end of an oocyte B. Antp protein injected into the posterior end of an embryo C. Toll mRNA injected into the dorsal side of an early embryo
The three homeodomain proteins Abd-B, Abd-A, andUbx are encoded by genes within the Bithorax complexof Drosophila. In wild-type embryos, the Abd-B gene isexpressed in the posterior abdominal segments, Abd-Ain the middle abdominal segments, and Ubx in the anterior abdominal and posterior thoracic segments. Whenthe Abd-B gene is deleted, Abd-A is expressed in both themiddle and the posterior abdominal segments. WhenAbd-A is deleted, Ubx is expressed in the posterior thoraxand in the anterior and middle abdominal segments.When Ubx is deleted, the patterns of Abd-A and Abd-Bexpression are unchanged from wild type. When bothAbd-A and Abd-B are deleted, Ubx is expressed in all segments from the posterior thorax to the posterior end ofthe embryo. Explain these observations, taking into consideration the fact that the gap genes control the initialexpression patterns of the homeotic genes
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