Chapter 17: Recombinant DNA and Biotechnology CHAPTER 17 Recombinant DNA and Biotechnology.

Chapter 17: Recombinant DNA and Biotechnology

CHAPTER 17Recombinant DNA and

Biotechnology


Chapter 17: Recombinant DNA and BiotechnologyCleaving and Rejoining DNACleaving and Rejoining DNA

Cloning GenesCloning Genes

Sources of Genes for CloningSources of Genes for Cloning

Some Additional Tools for DNA ManipulationSome Additional Tools for DNA Manipulation

Biotechnology: Applications of DNA Biotechnology: Applications of DNA

ManipulationManipulation


Cleaving and Rejoining DNA• Knowledge of DNA transcription, Knowledge of DNA transcription,

translation, and replication has been translation, and replication has been used to create recombinant DNA used to create recombinant DNA molecules, made up of sequences from molecules, made up of sequences from different organisms.different organisms.

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Cleaving and Rejoining DNA• Restriction enzymes, which are made Restriction enzymes, which are made

by microbes as a defense mechanism by microbes as a defense mechanism against viruses, bind to DNA at specific against viruses, bind to DNA at specific sequences and cut it. sequences and cut it.

Review Figure Review Figure 17.117.1

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17.1

Figure 17.1Figure 17.1

figure 17-01.jpgfigure 17-01.jpg


Cleaving and Rejoining DNA• DNA fragments generated from DNA fragments generated from

cleavage by restriction enzymes can be cleavage by restriction enzymes can be separated by size using gel separated by size using gel electrophoresis. electrophoresis.

• The fragments' sequences can be The fragments' sequences can be further identified by hybridization with a further identified by hybridization with a probe. probe.

Review Figures 17.2, 17.3Review Figures 17.2, 17.3

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17.2




17.3




Cleaving and Rejoining DNA• Many restriction enzymes make Many restriction enzymes make

staggered cuts in the two strands of staggered cuts in the two strands of DNA, creating “sticky ends” with DNA, creating “sticky ends” with unpaired bases. unpaired bases.

• The sticky ends can be used to create The sticky ends can be used to create recombinant DNA if DNA molecules from recombinant DNA if DNA molecules from different species are cut with the same different species are cut with the same restriction enzyme. restriction enzyme.

Review Figure 17.4Review Figure 17.4

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17.4




Cloning Genes

• Bacteria, yeasts, and cultured plant Bacteria, yeasts, and cultured plant cells are commonly used as hosts for cells are commonly used as hosts for recombinant DNA experiments.recombinant DNA experiments.

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Cloning Genes

• Newly introduced DNA must be part of Newly introduced DNA must be part of a replicon if it is to be propagated in a replicon if it is to be propagated in host cells. host cells.

• One way to assure this is to introduce One way to assure this is to introduce it as part of a carrier DNA, or vector, it as part of a carrier DNA, or vector, that has a replicon.that has a replicon.

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Cloning Genes

• Specialized vectors transfect bacteria, Specialized vectors transfect bacteria, yeasts, and plant cells. yeasts, and plant cells.

• These must contain a replicon, These must contain a replicon, recognition sequences for restriction recognition sequences for restriction enzymes, and genetic markers to enzymes, and genetic markers to identify their presence in host cells. identify their presence in host cells.


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17.5




Cloning Genes

• Naked DNA may be introduced into a Naked DNA may be introduced into a host cell by chemical or mechanical host cell by chemical or mechanical means. means.

• In this case, the DNA must integrate In this case, the DNA must integrate into the host DNA by itself.into the host DNA by itself.

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Cloning Genes

• When vectors carrying recombinant When vectors carrying recombinant DNA are incubated with host cells, DNA are incubated with host cells, nutritional, antibiotic resistance, or nutritional, antibiotic resistance, or fluorescent markers can identify which fluorescent markers can identify which cells contain the vector. cells contain the vector.


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17.6

Figure 17.6 – Part 1Figure 17.6 – Part 1

figure 17-06a.jpgfigure 17-06a.jpg


17.6


figure 17-06b.jpgfigure 17-06b.jpg


Sources of Genes for Cloning• The cutting of DNA by a restriction The cutting of DNA by a restriction

enzyme produces many fragments enzyme produces many fragments that can be individually and randomly that can be individually and randomly combined with a vector and inserted combined with a vector and inserted into a host to create a gene library. into a host to create a gene library.


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17.8




Sources of Genes for Cloning• The mRNA’s produced in a certain tissue The mRNA’s produced in a certain tissue

at a certain time can be extracted and at a certain time can be extracted and used to create complementary DNA used to create complementary DNA (cDNA) by reverse transcription. (cDNA) by reverse transcription.

• This cDNA is then used to make a This cDNA is then used to make a library. library.


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17.9




Sources of Genes for Cloning• A third source of DNA is synthetic DNA A third source of DNA is synthetic DNA

made in the laboratory. made in the laboratory.

• The methods of organic chemistry can The methods of organic chemistry can be used to create specific, mutated be used to create specific, mutated DNA sequences.DNA sequences.

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Some Additional Tools for DNA Manipulation

• Homologous recombination can be Homologous recombination can be used to “knock out” a gene in an used to “knock out” a gene in an organism. organism.


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• DNA chip technology permits the DNA chip technology permits the screening of thousands of sequences screening of thousands of sequences at the same time. at the same time.


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• An antisense RNA complementary to a An antisense RNA complementary to a specific mRNA can prevent its specific mRNA can prevent its translation by hybridizing to the translation by hybridizing to the mRNA. mRNA.


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Biotechnology: Applications of DNA Manipulation• The ability to clone genes has made The ability to clone genes has made

possible many new applications of possible many new applications of biotechnology, such as the large-scale biotechnology, such as the large-scale production of eukaryotic gene production of eukaryotic gene products.products.

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Biotechnology: Applications of DNA Manipulation• For a vector carrying a gene of interest For a vector carrying a gene of interest

to be expressed in a host cell, the to be expressed in a host cell, the gene must be adjacent to appropriate gene must be adjacent to appropriate sequences for its transcription and sequences for its transcription and translation in the host cell. translation in the host cell.


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Biotechnology: Applications of DNA Manipulation• Recombinant DNA and expression Recombinant DNA and expression

vectors have been used to make vectors have been used to make medically useful proteins that would medically useful proteins that would otherwise have been difficult to obtain otherwise have been difficult to obtain in necessary quantities. in necessary quantities.

Review Figure 17.14, Table 17.1Review Figure 17.14, Table 17.1

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17.14




17.1

Table 17.1Table 17.1

table 17-1.jpgtable 17-1.jpg


Biotechnology: Applications of DNA Manipulation• Because plant cells can be cloned to Because plant cells can be cloned to

produce adult plants, introduction of produce adult plants, introduction of new genes into plants via vectors has new genes into plants via vectors has been advancing rapidly. been advancing rapidly.

• The result is crop plants carrying new, The result is crop plants carrying new, useful genes. useful genes.

Review Table 17.2Review Table 17.2

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17.2

Table 17.2Table 17.2

table 17-2.jpgtable 17-2.jpg


Biotechnology: Applications of DNA Manipulation• ““Pharming” uses transgenic dairy Pharming” uses transgenic dairy

animals that produce useful products animals that produce useful products in their milk. in their milk.


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Biotechnology: Applications of DNA Manipulation• There is public concern about the There is public concern about the

applications of biotechnology to food applications of biotechnology to food production.production.

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Biotechnology: Applications of DNA Manipulation• Because the DNA of an individual is Because the DNA of an individual is

unique, the polymerase chain reaction unique, the polymerase chain reaction can be used to identify an organism can be used to identify an organism from a small sample of its cells, and to from a small sample of its cells, and to create a DNA fingerprint. create a DNA fingerprint.

Review Figures 17.17, 17.18Review Figures 17.17, 17.18

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17.18



Chapter 17: Recombinant DNA and Biotechnology CHAPTER 17 Recombinant DNA and Biotechnology.

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Transcript of Chapter 17: Recombinant DNA and Biotechnology CHAPTER 17 Recombinant DNA and Biotechnology.