Concept explainers
Figure 18.6 shows a picture of Glofish ®, transgenic zebrafish (Danio rerio) that express GFP, RFP, and some of their derivatives. Glofish® were the first GM pets. Genes can be transferred into the zebrafish genome using a transposable element called Tol2 from medaka fish (Oryzias latipes). The Tol2 transposon serves as a vector for gene transfer in a manner similar to Drosophila P elements as shown in Fig. 18.4. To use the Tol2 vector, researchers inject two-cell stage zebrafish embryos with two DNAs: One DNA expresses the Tol2 transposase gene, while the other recombinant transposon contains the transgene. If the transposon hops into a chromosome of a germ-line cell, a stable line of transgenic fish can be established.
Scientists have synthesized several different genes encoding derivatives of GFP and RFP. The derivatives have amino acid changes that alter their color, so that fish glowing green, red, orange, blue, or purple are available in many pet stores.
a. | Diagram the two recombinant DNA constructs needed to generate the fluorescent fish. |
b | Why is a transposon from medaka fish used rather than a zebrafish transposon? |
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EBK GENETICS: FROM GENES TO GENOMES
- A graduate student studying the pathogenic bacteria Acinetobacter baumannii made cDNA from planktonic cells and biofilm cells and performed RNA-Seq on both samples. She aligned her sequencing reads to a locus of the baumannii genome as shown. a. Which genes are on an operon together? Explain which data supports this? b. What is the most expressed transcript from the locus in Planktonic culture? c. Order the transcripts from largest increase in relative expression between biofilm and planktonic cells to the largest decrease in relative expression. d. When this data was compared to microarray transcriptional profiling, the microarray data provided lower expression levels for the most highly expressed transcripts. Why did this occur?arrow_forwardAnalyzing Cloned Sequences A base change (A to T) is the mutational event that created the mutant sickle cell anemia allele of beta globin. This mutation destroys an MstII restriction site normally present in the beta globin gene. This difference between the normal allele and the mutant allele can be detected with Southern blotting. Using a labeled beta globin gene as a probe, what differences would you expect to see for a Southern blot of the normal beta globin gene and the mutant sickle cell gene?arrow_forwardArrange the steps that would be used in a laboratory to engineer a bacterium that could express the human gene coding for factor VIII. (Not all steps will be placed).arrow_forward
- Given the following genotypes, explain, by answering the questions in each number, how the mutation (identified by a (-) superscript) will affect E. coli grown in lactose medium. Will there be a complete set ofgene products? (Yes/No) Will the lac operon be turnedon/off? Will the cell survive? (Yes/No) a. i + p + o + z - y + b. i + p - o + z + y + c. i + p + o - z + y +arrow_forwardA hypothetical gene for cephalosporin resistance is found to be carried by a transposon. Explain what a transposon is. Then explain how the cephalosporin resistance could be horizontally transferred between organisms by transformation, conjugation, and transduction. What steps/events would have to occur to allow the transposon to be transferred by each method. Also, explain how it could be transferred vertically between organisms.arrow_forwardYou are attempting to prepare a single gene knockout library using the pRL27 transposon system. You grow the donor E. coli in Luria broth containing both kanamycin and diaminopimelic acid (DAP) and your recipient Serratia rubidaea in plain Luria broth. You combine an equal ratio of donor and recipient cultures and plate the mixture onto Luria agar supplemented with DAP. After 24 hours incubation at 37°C, you create a cell slurry and plate the cells onto Luria agar aupplemented with kanamycin. After 24 hours incubation at 37°C, you find that no colonies grow. What best explains this outcome? A. Failure to supplement media with DAP B. Failure to remove antiobiotic containing media C. Failure to incubate for a sufficient length of time D. Failure to incubate at the appropiate temperature E. Failure to use the proper mating mix ratioarrow_forward
- Arrange the steps that would be used in a laboratory to engineer a bacterium that could express the human gene coding for factor VIII. Not all steps will be placed. Isolate the human gene that produces factor VIII. Isolate the mRNA of the factor VIII gene. Generate cDNA of the factor VIII gene using reverse transcriptase. Incorrect Insert the factor VIII cDNA into a bacterial vector near a promoter site. Transform the vector into an E. coli bacterium. Human DNA is introduced into the bacterial cell using direct injection by a small needle. E. coli expresses factor VIII. Answer Bank The factor VIII protein is isolated from human tissues.arrow_forwardArsenic is a toxic element found in both aquatic and terrestrial environments. Scientists have found genes that allow bacteria to remove arsenic from their cytoplasm. Arsenic enters cells as arsenate that must be converted to arsenite to leave cells. Figure 1 provides a summary of the arsenic resistance genes found in the operons of three different bacteria. E. coli R773 is found in environments with low arsenic levels. Herminiimonas arsenicoxydans and Ochrobactrum tritici are both found in arsenic‑rich environments. Researchers claim that bacteria that live in environments heavily contaminated with arsenic are more efficient at processing arsenic into arsenite and removing this toxin from their cells. Justify this claim based on the evidence shown in Figure 1. Both H. arsenicoxydans and O. tritici contain the arsR gene that codes for a repressor that turns on the operon to eliminate arsenite from the cell. Both O. tritici and E. coli contain the…arrow_forwardhelparrow_forward
- The genotypes of five merozygote bacteria are shown below. In each set, the genotype of the lac operon on the chromosome is on the left side of the slash (/) and the genotype of the lac operon on the F' plasmid is on the right side of the slash. Which of the merozygote bacteria listed below would be able to make high quantities of B-galactosidase in the absence of lactose? Mark all the answers that are correct. OIP*o*z* y*A*/F'I P oʻz*Y*A*. OI P o°z-Y*A*/F'IS P O*z*Y*A* nd of B * P*o*zY A /F'I P*o z*Y*A* erase e D I' P*o*z YA /F'I P*O z*Y* A* strand a NA poly should be 1S P*0°ZYA/FI P O*z*Y*A*arrow_forwardThe genotypes of five merozygote bacteria are shown below. In each set, the genotype of the lac operon on the chromosome is on the left side of the slash () and the genotype of the lac operon on the F' plasmid is on the right side of the slash. Which of the merozygote bacteria listed below would be able to make high quantities of B-galactosidase in the absence of lactose? Mark all the answers that are correct. O i p*o°z¯ y*A*/F'I$ p*oʻz*y*A* I* p* o*Z¯YA*/F'T P*O*z*y* A* I* P* o*z*Y* A* /F'T P*O*z*y* A* O 1* p*o*z° YA*/F'T P*o°z*y*A* 1S p*0°2¯Y¯AZET P*O*Z*Y*A*arrow_forwardExplain the difference in results for the RT-PCR from the CD4+ T cells and the RT-PCR from the CD8+T cells. (i.e., propose a conclusion)arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning