Concept explainers
A powerful approach to identifying genes of a developmental pathway is to screen for mutations that suppress or enhance the
a. A
b. In a complementary experiment, a gain
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Genetic Analysis: An Integrated Approach (3rd Edition)
- For the Igf2 gene, where do de novo methylation and maintenancemethylation occur?a. De novo methylation occurs in sperm, and maintenancemethylation occurs in egg cells.b. De novo methylation occurs in egg cells, and maintenancemethylation occurs in sperm cells.c. De novo methylation occurs in sperm, and maintenancemethylation occurs in somatic cells of offspring.d. De novo methylation occurs in egg cells, and maintenancemethylation occurs in somatic cells of offspring.arrow_forwardDiscuss how the anterior portion of the anteroposterior axis is established in Drosophila. What aspects of oogenesis are critical in establishing this axis? What do you think would happen if the bicoid mRNA was not trapped at the anterior end but instead diffused freely throughout the oocyte?arrow_forwardIn the sea urchin, early development may occur even in the presence of actinomycin D, which inhibits RNA synthesis. However, if actinomycin D is present early in development but is removed a few hours later, all development stops. In fact, if actinomycin D is present only between the sixth and eleventh hours of development, events that normally occur at the fifteenth hour are arrested. What conclusions can be drawn concerning the role of gene transcription between hours 6 and 15?arrow_forward
- a. The eyeless gene is required for eye formation in Drosophila. It encodes a homeodomain. What would you predict about the biochemical function of the Eyeless protein?b. Where would you predict that the eyeless gene is expressed in development? How would you test your prediction? c. The Small eye and Aniridia genes of mice and humans, respectively, encode proteins with very strong sequence similarity to the fly Eyeless protein, and they are named for their effects on eye development. Devise one test to examine whether the mouse and human genes are functionally equivalent to the fly eyeless gene.arrow_forwardIn 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.arrow_forwardYou found a strain of mutant fruit flies (Drosophila) living on the rotten bananas in your dorm room. You notice that many of the larvae have abnormal abdominal segments. You want to know if the “abdomenless” mutation is a maternal effect gene. Describe an experiment you would do to determine this, and the results that would support and contradict the notion that the abdomenless gene encodes a maternal determinant.arrow_forward
- You isolate a glp-1 mutation of C. elegans and discover that the DNA region encoding the spatial control region (SCR) has been deleted. What will the GLP-1 protein expression pattern be in a four-cell embryo in mutant heterozygotes? In mutant homozygotes?arrow_forwardAs shown in Figure 13-26, the Sonic hedgehog gene is expressed in many places in a developing chicken. Is theidentical Sonic hedgehog protein expressed in each tissue? If so, how do the tissues develop into different structures? If not, how are different Sonic hedgehog proteinsproduced?arrow_forwardMaternal and zygotic mRNAs regulate embryonic development by determining major body axes. Two of the these mRNAs code for the proteins ____ (of maternal origin) and (of zygotic origin), which are morphogens that accumulate at the end of the egg that will become the anterior end of the embryo, whereas two other mRNAs code for the morphogens ____ (maternal origin) and ____ (zygotic origin), which accumulate at the opposite end of the egg and determine the posterior end of the embryo. The dorso-ventral axis of the embryo is established by two morphogens coded for by maternal mRNAs: (1) ____, which is transcribed in the egg nucleus and accumulates in a crescent on the side of the egg that will become the dorsal surface; and (2) ____, which is transported after fertilization into blastodermal cells that will become the ventral surface, and in these cells activates the zygotic gene ____, which produces a protein that diffuses to the blatodermal cells at the opposite side of the egg and…arrow_forward
- Give typing answer with explanation and conclusion What characteristics of the DSX protein enable the female- and male-specific isoforms of DSX to regulate the same genes but with different outcomes in female and male development? [multiple answers possible] A.The two isoforms are different alleles of the same gene B.The two isoforms have different DNA-binding domains C.The two isoforms are lncRNAs involved in dosage compensation D.The two isoforms differ in their activation domain E.The two isoforms share the same activation domain F. The two isoforms share the same DNA-binding domainarrow_forwardIn this module, you have learned about the use of balancer chromosomes (such as TM2 and TM6C in the below crossing scheme) for isolating Drosophila mutants during EMS mutagenesis. Please inspect the following crossing scheme and choose which of the following statements is correct. A. TM6C is preferable over TM2 when performing mutagenesis B. EMS induces chromosomal inversion C. A balancer chromosome helps to isolate on which chromosome the mutant is located D. Following the above crossing scheme all flies with no TM2 or TM6C markers are mutantsarrow_forwardExplain the functional roles of maternal-effect genes, gap genes, pair-rule genes, and segment-polarity genes in Drosophila development.arrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning