Genetic Engineering Do you want a footer?

Introduction In the 1970s the field of Biotechnology exploded with the advent of methods producing recombinant DNA Recombinant DNA is formed when scientists combine pieces of DNA from two different sources Recombinant DNA technology is now widely used in genetic engineering (the manipulation of genes for practical purposes) Do you want a footer?

Applications Genetic Engineering has allowed us to… Mass produce insulin and many other important human proteins using bacteria, yeasts, and mammalian cells Produce many vaccines against infectious diseases Improve productivity & nutritional value of agriculturally important plants Do you want a footer?

Genetic Engineering Basics DNA is the “molecular” language that is common to all life. All living organisms use DNA to store their genetic information and direct protein synthesis. And because of this, organisms are capable of expressing genes unique to any other organisms or species Do you want a footer?

Genetic Engineering Basics Genetic engineering in practice is accomplished by… Isolating/obtaining a gene of interest Producing recombinant DNA (by inserting the gene of interest into another DNA molecule) Inserting the recombinant DNA into the host organism Do you want a footer?

Recombinant DNA Techniques Bacteria are the workhorses of modern biotechnology. To work with genes in the lab, biologists often use bacterial plasmids, small, circular DNA molecules that are separate from the much larger bacterial chromosome. Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution.

Recombinant DNA Techniques Plasmids: Easily incorporate foreign DNA Are readily taken up by bacterial cells Can act as vectors (DNA carriers that move genes from one cell to another) Are ideal for gene cloning (producing multiple identical copies of a gene-carrying piece of DNA) Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution.

Recombinant DNA Techniques Recombinant DNA techniques can help biologists produce large quantities of a desired protein. Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution.

Isolate DNA. Isolate plasmids. Cell containing the gene of interest Bacterial cell Plasmid DNA Recombinant DNA techniques can be used to produce large quantities of a desired protein and clone genes. Figure 12.8 Using recombinant DNA technology to produce useful products (Step 2)

Cut both DNAs with same enzyme. DNA fragments from cell Isolate DNA. Gene of interest Other genes Isolate plasmids. Cell containing the gene of interest Bacterial cell Plasmid DNA Figure 12.8 Using recombinant DNA technology to produce useful products (Step 3)

Cut both DNAs with same enzyme. DNA fragments from cell Isolate DNA. Gene of interest Other genes Mix the DNAs and join them together. Gene of interest Isolate plasmids. Cell containing the gene of interest Bacterial cell Recombinant DNA plasmids Plasmid DNA Figure 12.8 Using recombinant DNA technology to produce useful products (Step 4)

Cut both DNAs with same enzyme. DNA fragments from cell Isolate DNA. Gene of interest Other genes Mix the DNAs and join them together. Gene of interest Isolate plasmids. Cell containing the gene of interest Bacterial cell Recombinant DNA plasmids Bacteria take up recombinant plasmids. Plasmid DNA Recombinant bacteria Figure 12.8 Using recombinant DNA technology to produce useful products (Step 5)

Cut both DNAs with same enzyme. DNA fragments from cell Isolate DNA. Gene of interest Other genes Mix the DNAs and join them together. Gene of interest Isolate plasmids. Cell containing the gene of interest Bacterial cell Recombinant DNA plasmids Bacteria take up recombinant plasmids. Plasmid DNA Bacterial clone Recombinant bacteria Clone the bacteria. Figure 12.8 Using recombinant DNA technology to produce useful products (Step 6)

Cut both DNAs with same enzyme. DNA fragments from cell Isolate DNA. Gene of interest Other genes Mix the DNAs and join them together. Gene of interest Isolate plasmids. Cell containing the gene of interest Bacterial cell Recombinant DNA plasmids Bacteria take up recombinant plasmids. Plasmid DNA Bacterial clone Recombinant bacteria Clone the bacteria. Figure 12.8 Using recombinant DNA technology to produce useful products (Step 7) Find the clone with the gene of interest.

Cut both DNAs with same enzyme. DNA fragments from cell Isolate DNA. Gene of interest Other genes Mix the DNAs and join them together. Gene of interest Isolate plasmids. Cell containing the gene of interest Bacterial cell Recombinant DNA plasmids Bacteria take up recombinant plasmids. Plasmid DNA Bacterial clone Recombinant bacteria Clone the bacteria. Figure 12.8 Using recombinant DNA technology to produce useful products (Step 8) Find the clone with the gene of interest. Some uses of genes Some uses of proteins Gene for pest resistance Protein for dissolving clots Protein for “stone-washing” jeans Gene for toxic-cleanup bacteria The gene and protein of interest are isolated from the bacteria. Genes may be inserted into other organisms. Harvested proteins may be used directly.

Cutting and Pasting DNA via Restriction Enzymes Recombinant DNA is produced by combining two ingredients: A bacterial plasmid The gene of interest To combine these ingredients, a piece of DNA must be spliced into a plasmid. Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution. © 2010 Pearson Education, Inc.

Cutting and Pasting DNA via Restriction Enzymes This splicing process can be accomplished by: Using restriction enzymes, which cut DNA at specific nucleotide sequences and Producing pieces of DNA called restriction fragments with “sticky ends” important for joining DNA from different sources DNA ligase connects the DNA pieces into continuous strands by forming bonds between adjacent nucleotides. Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution.

Cutting & Pasting DNA Figure 12.9 Cutting and pasting DNA (Step 4)

Obtaining the Gene of Interest How can a researcher obtain DNA that encodes a particular gene of interest? A “shotgun” approach yields millions of recombinant plasmids carrying many different segments of foreign DNA. A collection of cloned DNA fragments that includes an organism’s entire genome (a complete set of its genes) is called a genomic library. Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution.

Obtaining a gene of interest Methods for detecting a gene of interest depend on the nucleotide sequence of the gene. When at least part of the nucleotide sequence of a gene is known, scientists can use nucleic acid probes to find the gene

Nucleic Acid Probes A nucleic acid probe is a short sequence of nucleotides that is complimentary to the sequence of the gene of interest. The probe is also labeled with a radioactive isotope or a fluorescent dye.

Obtaining a gene of interest Another way to obtain a gene of interest is to: Use reverse transcriptase and Synthesize the gene by using an mRNA template Student Misconceptions and Concerns 1. The roles of restriction enzymes and nucleic acid probes, as well as many other aspects of recombinant DNA techniques, rely upon a firm and comfortable understanding of basic molecular genetics. Consider addressing Chapter 12 after an exam that addresses the content in Chapters 10 and 11. 2. Students might bring some awareness and/or concerns about biotechnology to the classroom, for example, controversies regarding genetically modified (GM) foods. This experience can be used to generate class interest and to highlight the importance of good information when making judgments. Consider starting class with a headline addressing one of these issues. Teaching Tips 1. Annual flu vaccinations are a common example of using vaccines to prevent diseases that cannot be easily cured. However, students might not understand why many people receive the vaccine every year. A new annual vaccine is necessary because the flu viruses keep evolving. 2. Genetically engineered organisms are controversial, creating various degrees and directions of social resistance. Yet, many debates around issues of science are confused by misinformation. This may be an opportunity for you to make an extra credit or regular assignment for students to take a position, one side or the other, on some aspect of this or related issues. The science would need to be accurate. Students might debate whether a food product made from GM/transgenic organisms should be labeled as such, or students can discuss the risks or advantages of producing GM organisms. 3. The origin of the name “restriction enzymes” may be of interest. In nature, these enzymes protect bacterial cells against foreign DNA. Thus, these enzymes “restrict” the invasion of foreign genetic material. 4. The ability to swap genes between prokaryotes and eukaryotes using the technologies described in this chapter reveal the fundamental genetic mechanisms shared by all forms of life. This very strong evidence of common descent is a lesson about evolution that may be missed by your students. 5. Students might think you are just making a bad joke by noting that laboratory-synthesized genes are “designer genes,” but this is a common term. Search the Internet using the keywords “designer genes,” and many scientific (and unscientific) sites will be found. 6. A genomic library of the sentence you are now reading would be all of the sentence fragments that make up the sentence. One could string together all of the words of this first sentence, without spaces between letters, and then conduct a word-processing edit placing a space between any place where an “e” is followed by the letter “n” The resulting fragments of this original sentence would look like this, and would be like a type of “genomic library.” Age nomiclibraryofthese nte nceyouare nowreadingwouldbeallofthese nte ncefragme ntsthatmadeupthese nte nce. 7. Some Internet search programs rely upon a methodology similar in one way to the use of a nucleic acid probe. For example, if you want to find the lyrics to a particular song, but you do not know the song title or artist, you might search the Internet using a unique phrase from the song. (For example, search using “yellow submarine”.) The search engine will scan millions of web pages to identify those sites containing that particular phrase. However, unlike a nucleic acid probe, you would search for the song by using a few of the lyrics. A nucleic acid probe would search using a sequence complementary to the desired sequence. 8. Roundup Ready Corn, a product of Monsanto, is resistant to the herbicide Roundup. The general strategy for farmers is to spray fields of Roundup Ready corn with the herbicide Roundup, killing weeds but not the corn. A search of the Internet will quickly reveal the controversy associated with this and other genetically modified organisms (GMO), which can encourage interesting discussions and promote critical thinking skills. 9. As gene therapy technology expands, our ability to modify the genome in human embryos, created through in vitro fertilization, permits genetic modification at the earliest stages of life. Future generations of humans, like our crops today, may include those with and without a genetically modified ancestry. The benefits and challenges of these technologies raise issues many students have never considered. Our students, and the generations soon to follow, will face the potential of directed human evolution.

Obtaining a gene of interest Another approach is to: Use an automated DNA-synthesizing machine and Synthesize a gene of interest from scratch