{"id":91,"date":"2020-08-20T16:43:50","date_gmt":"2020-08-20T20:43:50","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/kathleef\/?post_type=chapter&#038;p=91"},"modified":"2025-06-16T16:20:40","modified_gmt":"2025-06-16T20:20:40","slug":"chapter-16-applications-of-pcr","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-16-applications-of-pcr\/","title":{"raw":"Further Applications of PCR","rendered":"Further Applications of PCR"},"content":{"raw":"<h1 style=\"text-align: center\">Introduction<\/h1>\r\nIn this section we'll look at some applications of PCR, beyond those already covered in the alternative cloning approaches and traditional cloning chapters. You will already appreciate that we can add sequences to PCR primers so that we can amplify products that can be cut with certain enzymes or generate overhangs for ligase independent cloning.\r\n\r\nBut we can use PCR for other purposes as well.\r\n\r\nIn terms of making transgenic organisms, we can use PCR to introduce mutations into DNA sequences in order to study the function of the gene.\u00a0 We can also use PCR to fuse two sequences together- as always, primer design is key here and the primers include sequence overlaps between the two pieces to be combined (you have seen the same concept in the SLIC cloning chapter).\r\n\r\nOnce the transgenic organism is produced, we can also use PCR as a way to confirm the presence of the transgene in the organism, determine the exact location of the transgene, and test individuals to find out if they are homozygous or heterozygous for the inserted DNA.\r\n\r\nThis recordi<span style=\"text-align: initial;font-size: 1em\">ng covers a few basics about add<\/span><span style=\"text-align: initial;font-size: 1em\">ing nucleotides to primers for cloning purposes. An example is adding restriction sites to primers so that an insert can be cloned directionally. It is mainly review. <\/span><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-1.ppt\">Click here for the powerpoint slides<\/a><span style=\"text-align: initial;font-size: 1em\">.<\/span>\r\n\r\n[embed]https:\/\/www.youtube.com\/watch?v=oBNHhz5z4eE&amp;feature=youtu.be&amp;hd=1[\/embed]\r\n<div class=\"textbox shaded\">\r\n<h2 style=\"margin-top: 0em\">Contents<\/h2>\r\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 0em\"><a href=\"#Learning_Outcomes\">Learning Outcomes<\/a>\r\n<a href=\"#A_site\">A. Site-directed mutagenesis<\/a><\/p>\r\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 2em\"><a href=\"#A1_types\">A-1. Types of changes that can be introduced<\/a>\r\n<a href=\"#A2_using\">A-2. Using the genomic DNA as template<\/a>\r\n<a href=\"#A3_using\">A-3. Using the cloned gene in a plasmid as a template<\/a><\/p>\r\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 0em\"><a href=\"#B_fusion\">B. Fusion PCR<\/a>\r\n<a href=\"#C_PCR\">C. PCR on transgenic organisms<\/a><\/p>\r\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 2em\"><a href=\"#C1_confirmation\">C-1. Confirmation of the presence of the foreign DNA<\/a>\r\n<a href=\"#C2_determining\">C-2. Determining the position of the transgene<\/a>\r\n<a href=\"#C3_checking\">C-3. Checking for homozygosity or heterozygosity<\/a><\/p>\r\n&nbsp;\r\n\r\n<a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/back-matter\/recorded-lecture-videos\/#16\">List of lecture videos (excluding supplemental videos)<\/a>\r\n\r\n<\/div>\r\n\r\n<hr style=\"height: 5px;border-top: solid black\" \/>\r\n\r\n<div class=\"textbox textbox--learning-objectives\"><header class=\"textbox__header\">\r\n<h2 class=\"textbox__title\" style=\"margin-top: 0em;margin-bottom: 0em\"><a id=\"Learning_Outcomes\"><\/a>Learning Outcomes<\/h2>\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n<ul>\r\n \t<li><span style=\"text-decoration: underline\">Describe and explain<\/span> the processes described in the chapter<\/li>\r\n \t<li>Given a gene of interest, and any needed information, <span style=\"text-decoration: underline\">design primers<\/span> to generate specified mutations in the GOI<\/li>\r\n \t<li>Given the results of a PCR on a transgenic organism, be able to <span style=\"text-decoration: underline\">interpret<\/span> the results about whether the organism has the transgene and if it is homozygous or heterozygous for it<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n\r\n<hr style=\"height: 5px;border-top: solid black\" \/>\r\n\r\n<h2><a id=\"A_site\"><\/a>A. Site-directed mutagenesis:<\/h2>\r\nYou can use PCR to introduce mutations into a GOI by introducing the change you want in the gene into the primers. You have already seen this in action in the Molecular Cloning simulation worksheet - a primer was designed to remove the stop codon of the <em>Rad52<\/em> gene and to simultaneously introduce an <em>Xba<\/em>I site in order to fuse <em>Rad52<\/em> to <em>GFP<\/em> in frame.\u00a0 Just two nucleotides were \"mismatch\" nucleotides in the primer and this can be tolerated so long as the mismatches are not at the 3' end of a primer. When the PCR product is amplified all the products contain the primer or its complement and thus have the desired mutation. This use of a primer with a small number of mismatches, to induce a particular chan<span style=\"text-align: initial;font-size: 1em\">ge in a gene sequence is an example of site directed mutagenesis.<\/span>\r\n\r\n&nbsp;\r\n\r\n<hr \/>\r\n\r\n<h3><a id=\"A1_types\"><\/a>A-1. Types of changes that can be introduced<\/h3>\r\nAll of these are genetic changes that can be introduced into a gene of interest:\r\n<ul>\r\n \t<li>Insertion of nucleotides for the purposes of tagging the protein (6-his e.g.) or for other purposes such as generating a restriction enzyme site or additional amino acids that may alter a gene's function<\/li>\r\n \t<li>Removal of a stop codon, usually to allow fusion to a reporter gene<\/li>\r\n \t<li>Introduction of a stop codon to truncate the protein product<\/li>\r\n \t<li>Change of key amino acids suspected to be crucial to protein function<\/li>\r\n \t<li>Deletion of key amino acids suspected to be crucial to protein function<\/li>\r\n<\/ul>\r\nThese generally fall under 3 main categories: <span style=\"text-decoration: underline\">point mutations<\/span> (changes in a single amino acid, so the alternation of 1-3 nucleotides in a gene), <span style=\"text-decoration: underline\">insertions<\/span> (the addition of one or more nucleotides to a gene), and <span style=\"text-decoration: underline\">deletions<\/span> (the removal of one or more nucleotides from a gene).\r\n\r\n[h5p id=\"68\"]\r\n\r\n[h5p id=\"69\"]\r\n\r\n<hr \/>\r\n\r\n<h3><a id=\"A2_using\"><\/a>A-2. Using the genomic DNA as a template<\/h3>\r\nWhen we u<span style=\"text-align: initial;font-size: 1em\">se the genomic DNA as a template there are limitations in the mutations to be introduced. The mutations are introduced in via primers and rely on the fact that we the primer can bind to the template despite a few mismatches if we alter the stringency conditions. We lower the annealing temperature to a point where the small number of mismatches won't prevent primer binding to the intended target sequence. We cannot drop the temperature too low, though, or we may amplify artifacts. Touchdown PCR would be a good approach in this case (see <\/span><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-5-polymerase-chain-reaction-pcr-the-basics\/\">Chapter 5<\/a><span style=\"text-align: initial;font-size: 1em\"> for a review of touchdown PCR if you don't remember what it is).<\/span>\r\n\r\nThe mutations introduced are limited to the ends of the PCR products, since they are in the primer sequences. You can introduce mutations into the middle of a gene but this requires performing multiple PCRs and then the different PCR products would need to be correctly combined through restriction enzymes, or SLIC cloning, to assemble the complete gene containing the introduced mutations. Attention to reading frame would be essential to this process. It is a lot of work.\r\n\r\n&nbsp;\r\n\r\n<hr \/>\r\n\r\n<h3><a id=\"A3_using\"><\/a>A-3. Using the cloned gene in a plasmid as a template<\/h3>\r\nMaking mutations in a GOI from a plasmid insert is easier because of the circularity of the plasmid. You can place the primers wherever you wish, directed away from each other, and incorporating the desired change. This results in a linear PCR product which can then be ligated back into a circular plasmid that now contains the gene of interest with the desired mutation.\u00a0 The process is described in the recording. It will help to draw the results of the PCRs to see how each type of mutation: point mutation, insertion, or deletion, is generated. The following sections focus on the sequence and placement of the primers, in order to generate the desired mutation.\r\n<h4>A-3i. Making point mutations<\/h4>\r\nTo introduce a point mutation, the primers are directed away from each other, with no overlap and no nucleotides between them. As you are trying to alter one amino acid to another, you will have one mutagenic primer, that contains a mismatch of 1 -3 nucleotides. It depends on how many nucleotides must be changed to change the resulting amino acid.\r\n<h4>A-3ii. Making deletions<\/h4>\r\nIn order to make deletions, neither primer needs to be mutagenic. Both can perfectly match the template sequence, but you place them to either side of the sequence you want to delete. When the PCR product is amplified, it will lack those nucleotides and when the product is religated, you now have a version of your gene that is missing those nucleotides and thus a protein product that is missing those amino acids.\r\n<h4>A-3iii. Making insertions<\/h4>\r\nIf the insertion you want to introduce into the gene is small, perhaps just one codon (three nucleotides), you can add the sequence to the middle of the mutagenic primer.\u00a0 This is option 2 in the recording. However if the insertion is longer- multiple amino acids - then the extra sequence is added to the 5' end of one of the primers. The gene specific parts of the primers are right next to each other, so there is no overlap between them, nor any nucleotides between them.\r\n\r\n<img class=\"alignnone size-large wp-image-1138\" style=\"font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primer-placement.png\" alt=\"\" width=\"343\" height=\"113\" \/>\r\n\r\n[h5p id=\"70\"]\r\n\r\n<img class=\"alignnone size-full wp-image-1137\" style=\"font-size: 1em;font-style: italic\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/econd-primer-placement.png\" alt=\"\" width=\"343\" height=\"112\" \/>\r\n\r\n[h5p id=\"71\"]\r\n\r\n<a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-2.ppt\">Click here for the powerpoint slides<\/a>.\r\n\r\n[embed]https:\/\/www.youtube.com\/watch?v=sfcthBxFN0o&amp;feature=youtu.be&amp;hd=1[\/embed]\r\n\r\n<hr style=\"height: 5px;border-top: solid black\" \/>\r\n\r\n<h2><a id=\"B_fusion\"><\/a>B. Fusion PCR:<\/h2>\r\nFusion PCR is a PCR-based method of combining two sequences. It works well in some instances; we\u2019ve done this in BISC 357 in the past with variable success. It requires careful pipetting and more time spent purifying the products etc than we really have time for in the class.\r\n\r\nIn this method, you PCR amplify the two pieces you want to combine with some overlapping sequence on the primers- similar to how it is done with SLIC. The image below shows the two PCR products generated in preparation for fusion PCR. The first amplicon (blue) has a reverse primer that has a 5' end complementary to the forward primer of the second amplicon (red).\u00a0 The two PCR reactions are amplified separately, and when the first one is complete, it has sequence at its 3' end that matches the 5' end of the second amplicon, shown with colour coding.\r\n\r\n<img class=\"alignnone size-large wp-image-927\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-1024x430.jpg\" alt=\"\" width=\"1024\" height=\"430\" \/>\r\n\r\nThe two pieces are amplified separately and then the products are column purified, which is essential because we need to get rid of all the primers that are in the reactions. If there is a lot of background, we might gel purify the products that are the correct size to enhance the likelihood of success.\r\n\r\nThen we combine the products of the two PCR reactions together in equal amounts, in a tube with primers specific for the forward end of the first product (1F) and the reverse end of the other (2R). The two products can bind to each other due to the overlapping sequences generated on the amplicon, and there are two orientations where this is possible. \u00a0In one orientation nothing will happen because the recessed ends are 5\u2019 ends. However, in the other orientation the recessed ends are 3\u2019 ends and in the first cycle, Taq polymerase can extend these as it would any primer - generating strands of DNA that now include the combined fragments.\r\n\r\nThe image below shows this. The strands of the products are labeled A through D for the purposes of the explanation. There are four ways that the DNA strands can bind. A and B can bind and C and D can bind. These strands can't be extended. Strand C and B can bind each other as well, due to the overlapping complementary region.\u00a0 If they do, as shown below, no extension of the strands can occur as the recessed ends are both 5' ends. Finally strands A and D can also bind each other due to their overlapping region. In this case, the recessed ends are 3' ends which can be extended by Taq.\u00a0 The result will be that the A and D strands will be extended to generate the full length desired product.\r\n\r\n<img class=\"alignnone size-large wp-image-928\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-1024x692.jpg\" alt=\"\" width=\"1024\" height=\"692\" \/>\r\n\r\nIn the next cycle the primers 1F and 2R that match the ends of the combined fragment can make the complementary strands.\u00a0 This generates a PCR product that has fused the two amplicons from the first reaction into a single larger amplicon. The alignment of the A and D strands of DNA will not happen frequently in the PCR reaction but even if it occurs occasionally, that will be enough to generate a fusion product. This is the power of PCR.\u00a0<span style=\"background-color: #ffff99\"><em> Study tip: You should draw this out with a few nucleotides indicating the \"overlap\" sequence to ensure you understand it.<\/em><\/span>\r\n\r\n<a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-3.ppt\">Click here for the powerpoint slides<\/a>.\r\n\r\n[embed]https:\/\/www.youtube.com\/watch?v=wDo5KqXe2VE&amp;feature=youtu.be&amp;hd=1[\/embed]\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<hr style=\"height: 5px;border-top: solid black\" \/>\r\n\r\n<h2><a id=\"C_PCR\"><\/a>C. PCR on transgenic organisms:<\/h2>\r\n<h3><a id=\"C1_confirmation\"><\/a>C-1. Confirmation of the presence of the foreign DNA<\/h3>\r\nIf we have generated organisms that we think are transgenic, we want to confirm that the transgene is incorporated in the genome.\u00a0 We can use gene specific primers that should recognize only the introduced DNA. These will only generate a product if the transgene is present. Clearly, it cannot be a gene that naturally occurs in the organism.\u00a0 And the positive and negative controls are really important.\u00a0 If we don\u2019t see a band, we want to be sure that this is a real negative result \u2013 that the organism really doesn\u2019t have our transgene. Which control is the most important one to reassure us that we COULD have amplified the band if the gene was present?\u00a0 If we do see a band, we want to be sure this band was amplified from the template we added and not some contaminating DNA. Which control lets us feel confident that our bands indicate a real positive result rather than a contaminant?\r\n\r\n[h5p id=\"72\"]\r\n\r\n<hr \/>\r\n\r\n<h3><a id=\"C2_determining\"><\/a>C-2. Determining the position of the transgene<\/h3>\r\nWe can use<strong><span style=\"color: #0000ff\"> inverse PCR<\/span><\/strong> to determine where in the genome our foreign DNA is inserted. We use the sequence we do know to identify the sequence we don\u2019t know but want to know.\r\n\r\nWe start by cutting the genomic DNA with a restriction enzyme that we know does not cut inside our construct. This cuts the genome into many pieces. Then a ligation is performed in a very large volume to ensure that the DNA is very dilute. In this case, the closest free end that the DNA can ligate with is on the same molecule. This favours circularization of the DNA pieces.\r\n\r\nThen PCR is performed using primers that recognize the edges of the construct and are directed outward. The product that is made consists of the sequence to either side of the construct. We only need perhaps 30 or 40 nucleotides of sequence to pinpoint unique sites in the genome unless our construct is in the midst of a repeat sequence.\r\n\r\n<em>\u00a0<\/em>\r\n\r\n<hr \/>\r\n\r\n<h3><a id=\"C3_checking\"><\/a>C-3. Checking for homozygosity or heterozygosity<\/h3>\r\nWhen we have transgenic organisms, we want to know whether they are homozygous or heterozygous for the construct. In this case we use our information obtained from part C-2 and we design a primer set in which one forward primer recognizes the insert and the other forward primer recognizes sequence upstream of the insert. The reverse primer recognizes sequence downstream of the insert. Depending on whether or not the insert is in the DNA, you will either get a band from the combination of the insert-specific primer plus the reverse primer, or from the upstream specific primer combined with the reverse primer. It is important that:\r\n<ol>\r\n \t<li>The band sizes for each pair of primers is different and easy to distinguish.<\/li>\r\n \t<li>The insert is so large that if it is present in the DNA, the second forward primer will be unable to generate a band with the reverse primer.<\/li>\r\n<\/ol>\r\nIn the image below, the three primers are shown on the upper chromosome, which has the insert (in orange) and the two primers are shown on the lower chromosome, which does not have the insert. The expected band sizes are just an example. The insert is not to scale. Assume that it is about 8-`15 kb in length.\r\n\r\n&nbsp;\r\n\r\n<img class=\"alignnone size-full wp-image-907\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous.jpg\" alt=\"\" width=\"1941\" height=\"695\" \/>\r\n\r\nWhen the PCRs are run on a gel, the band sizes tell us whether the individual is homozygous for the normal chromosome (1.5 kb band), homozygous for the inserted chromosome (1 kb), or heterozygous (one of each type of chromosome, one 1.5 and one 1.). Please ensure that you understand the image above and the gel schematic below.\r\n\r\n<img class=\"wp-image-924 alignleft\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous.jpg\" alt=\"\" width=\"347\" height=\"323\" \/>\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nHere are some images for the self-test questions below. The first shows an image of a gene on a chromosome, one version with no inserted transgene and one version with an inserted transgene. Three primers are shown: F1 is the forward primer that recognizes the F' end of the gene and R is the reverse primer that recognizes the 3' end of the gene. F2 is a forward primer that recognizes the transgene. Please note that the schematic is not to scale. The GOI is about 1.5 kb in length, while the transgene is about 10 kb in length.\r\n\r\n<img class=\"wp-image-1146 alignleft\" style=\"font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers.png\" alt=\"\" width=\"444\" height=\"148\" \/>\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nBelow are images that show the chromosome constitutions of three different individuals. Please answer the questions below each image, about the individual shown in that image.\r\n\r\n<img class=\"alignnone size-full wp-image-1144\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert.png\" alt=\"\" width=\"389\" height=\"69\" \/>\r\n\r\n[h5p id=\"75\"]\r\n\r\n[h5p id=\"76\"]\r\n\r\n<img class=\"alignnone size-full wp-image-1145\" style=\"text-align: initial;font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal.png\" alt=\"\" width=\"383\" height=\"72\" \/>\r\n\r\n[h5p id=\"74\"]\r\n\r\n[h5p id=\"73\"]\r\n\r\n<img class=\"alignnone size-full wp-image-1143\" style=\"font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous.png\" alt=\"\" width=\"388\" height=\"74\" \/>\r\n\r\n[h5p id=\"77\"]\r\n\r\n[h5p id=\"78\"]\r\n\r\n<strong><span style=\"color: #800000\">Please note t<\/span><\/strong><strong style=\"text-align: initial;font-size: 1em\"><span style=\"color: #800000\">hat there is an error in the recording for iPCR. The sequencing primers are the same ones used in the PCR.\u00a0\u00a0<\/span><\/strong>\r\n\r\n<a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-4.ppt\">Click here for the powerpoint slides<\/a>.\r\n\r\n[embed]https:\/\/www.youtube.com\/watch?v=aEEV2EpuV7E&amp;feature=youtu.be&amp;hd=1[\/embed]\r\n\r\n&nbsp;\r\n<p style=\"text-align: left\"><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-15-alternative-methods-of-cloning-3-slic\/\">Previous (Chapter 15)<\/a><span style=\"float: right\"><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-17-introducing-dna-into-cells\/\">Next (Chapter 17)<\/a><\/span><\/p>","rendered":"<h1 style=\"text-align: center\">Introduction<\/h1>\n<p>In this section we&#8217;ll look at some applications of PCR, beyond those already covered in the alternative cloning approaches and traditional cloning chapters. You will already appreciate that we can add sequences to PCR primers so that we can amplify products that can be cut with certain enzymes or generate overhangs for ligase independent cloning.<\/p>\n<p>But we can use PCR for other purposes as well.<\/p>\n<p>In terms of making transgenic organisms, we can use PCR to introduce mutations into DNA sequences in order to study the function of the gene.\u00a0 We can also use PCR to fuse two sequences together- as always, primer design is key here and the primers include sequence overlaps between the two pieces to be combined (you have seen the same concept in the SLIC cloning chapter).<\/p>\n<p>Once the transgenic organism is produced, we can also use PCR as a way to confirm the presence of the transgene in the organism, determine the exact location of the transgene, and test individuals to find out if they are homozygous or heterozygous for the inserted DNA.<\/p>\n<p>This recordi<span style=\"text-align: initial;font-size: 1em\">ng covers a few basics about add<\/span><span style=\"text-align: initial;font-size: 1em\">ing nucleotides to primers for cloning purposes. An example is adding restriction sites to primers so that an insert can be cloned directionally. It is mainly review. <\/span><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-1.ppt\">Click here for the powerpoint slides<\/a><span style=\"text-align: initial;font-size: 1em\">.<\/span><\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Chapter 16 recording 1 add sequence to primers\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/oBNHhz5z4eE?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<div class=\"textbox shaded\">\n<h2 style=\"margin-top: 0em\">Contents<\/h2>\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 0em\"><a href=\"#Learning_Outcomes\">Learning Outcomes<\/a><br \/>\n<a href=\"#A_site\">A. Site-directed mutagenesis<\/a><\/p>\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 2em\"><a href=\"#A1_types\">A-1. Types of changes that can be introduced<\/a><br \/>\n<a href=\"#A2_using\">A-2. Using the genomic DNA as template<\/a><br \/>\n<a href=\"#A3_using\">A-3. Using the cloned gene in a plasmid as a template<\/a><\/p>\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 0em\"><a href=\"#B_fusion\">B. Fusion PCR<\/a><br \/>\n<a href=\"#C_PCR\">C. PCR on transgenic organisms<\/a><\/p>\n<p style=\"margin-top: 0em;margin-bottom: 0em;margin-left: 2em\"><a href=\"#C1_confirmation\">C-1. Confirmation of the presence of the foreign DNA<\/a><br \/>\n<a href=\"#C2_determining\">C-2. Determining the position of the transgene<\/a><br \/>\n<a href=\"#C3_checking\">C-3. Checking for homozygosity or heterozygosity<\/a><\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/back-matter\/recorded-lecture-videos\/#16\">List of lecture videos (excluding supplemental videos)<\/a><\/p>\n<\/div>\n<hr style=\"height: 5px;border-top: solid black\" \/>\n<div class=\"textbox textbox--learning-objectives\">\n<header class=\"textbox__header\">\n<h2 class=\"textbox__title\" style=\"margin-top: 0em;margin-bottom: 0em\"><a id=\"Learning_Outcomes\"><\/a>Learning Outcomes<\/h2>\n<\/header>\n<div class=\"textbox__content\">\n<ul>\n<li><span style=\"text-decoration: underline\">Describe and explain<\/span> the processes described in the chapter<\/li>\n<li>Given a gene of interest, and any needed information, <span style=\"text-decoration: underline\">design primers<\/span> to generate specified mutations in the GOI<\/li>\n<li>Given the results of a PCR on a transgenic organism, be able to <span style=\"text-decoration: underline\">interpret<\/span> the results about whether the organism has the transgene and if it is homozygous or heterozygous for it<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<hr style=\"height: 5px;border-top: solid black\" \/>\n<h2><a id=\"A_site\"><\/a>A. Site-directed mutagenesis:<\/h2>\n<p>You can use PCR to introduce mutations into a GOI by introducing the change you want in the gene into the primers. You have already seen this in action in the Molecular Cloning simulation worksheet &#8211; a primer was designed to remove the stop codon of the <em>Rad52<\/em> gene and to simultaneously introduce an <em>Xba<\/em>I site in order to fuse <em>Rad52<\/em> to <em>GFP<\/em> in frame.\u00a0 Just two nucleotides were &#8220;mismatch&#8221; nucleotides in the primer and this can be tolerated so long as the mismatches are not at the 3&#8242; end of a primer. When the PCR product is amplified all the products contain the primer or its complement and thus have the desired mutation. This use of a primer with a small number of mismatches, to induce a particular chan<span style=\"text-align: initial;font-size: 1em\">ge in a gene sequence is an example of site directed mutagenesis.<\/span><\/p>\n<p>&nbsp;<\/p>\n<hr \/>\n<h3><a id=\"A1_types\"><\/a>A-1. Types of changes that can be introduced<\/h3>\n<p>All of these are genetic changes that can be introduced into a gene of interest:<\/p>\n<ul>\n<li>Insertion of nucleotides for the purposes of tagging the protein (6-his e.g.) or for other purposes such as generating a restriction enzyme site or additional amino acids that may alter a gene&#8217;s function<\/li>\n<li>Removal of a stop codon, usually to allow fusion to a reporter gene<\/li>\n<li>Introduction of a stop codon to truncate the protein product<\/li>\n<li>Change of key amino acids suspected to be crucial to protein function<\/li>\n<li>Deletion of key amino acids suspected to be crucial to protein function<\/li>\n<\/ul>\n<p>These generally fall under 3 main categories: <span style=\"text-decoration: underline\">point mutations<\/span> (changes in a single amino acid, so the alternation of 1-3 nucleotides in a gene), <span style=\"text-decoration: underline\">insertions<\/span> (the addition of one or more nucleotides to a gene), and <span style=\"text-decoration: underline\">deletions<\/span> (the removal of one or more nucleotides from a gene).<\/p>\n<div id=\"h5p-68\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-68\" class=\"h5p-iframe\" data-content-id=\"68\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"SIte directed mutagenesis 1\"><\/iframe><\/div>\n<\/div>\n<div id=\"h5p-69\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-69\" class=\"h5p-iframe\" data-content-id=\"69\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Site directed mutagenesis 2\"><\/iframe><\/div>\n<\/div>\n<hr \/>\n<h3><a id=\"A2_using\"><\/a>A-2. Using the genomic DNA as a template<\/h3>\n<p>When we u<span style=\"text-align: initial;font-size: 1em\">se the genomic DNA as a template there are limitations in the mutations to be introduced. The mutations are introduced in via primers and rely on the fact that we the primer can bind to the template despite a few mismatches if we alter the stringency conditions. We lower the annealing temperature to a point where the small number of mismatches won&#8217;t prevent primer binding to the intended target sequence. We cannot drop the temperature too low, though, or we may amplify artifacts. Touchdown PCR would be a good approach in this case (see <\/span><a style=\"text-align: initial;font-size: 1em\" href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-5-polymerase-chain-reaction-pcr-the-basics\/\">Chapter 5<\/a><span style=\"text-align: initial;font-size: 1em\"> for a review of touchdown PCR if you don&#8217;t remember what it is).<\/span><\/p>\n<p>The mutations introduced are limited to the ends of the PCR products, since they are in the primer sequences. You can introduce mutations into the middle of a gene but this requires performing multiple PCRs and then the different PCR products would need to be correctly combined through restriction enzymes, or SLIC cloning, to assemble the complete gene containing the introduced mutations. Attention to reading frame would be essential to this process. It is a lot of work.<\/p>\n<p>&nbsp;<\/p>\n<hr \/>\n<h3><a id=\"A3_using\"><\/a>A-3. Using the cloned gene in a plasmid as a template<\/h3>\n<p>Making mutations in a GOI from a plasmid insert is easier because of the circularity of the plasmid. You can place the primers wherever you wish, directed away from each other, and incorporating the desired change. This results in a linear PCR product which can then be ligated back into a circular plasmid that now contains the gene of interest with the desired mutation.\u00a0 The process is described in the recording. It will help to draw the results of the PCRs to see how each type of mutation: point mutation, insertion, or deletion, is generated. The following sections focus on the sequence and placement of the primers, in order to generate the desired mutation.<\/p>\n<h4>A-3i. Making point mutations<\/h4>\n<p>To introduce a point mutation, the primers are directed away from each other, with no overlap and no nucleotides between them. As you are trying to alter one amino acid to another, you will have one mutagenic primer, that contains a mismatch of 1 -3 nucleotides. It depends on how many nucleotides must be changed to change the resulting amino acid.<\/p>\n<h4>A-3ii. Making deletions<\/h4>\n<p>In order to make deletions, neither primer needs to be mutagenic. Both can perfectly match the template sequence, but you place them to either side of the sequence you want to delete. When the PCR product is amplified, it will lack those nucleotides and when the product is religated, you now have a version of your gene that is missing those nucleotides and thus a protein product that is missing those amino acids.<\/p>\n<h4>A-3iii. Making insertions<\/h4>\n<p>If the insertion you want to introduce into the gene is small, perhaps just one codon (three nucleotides), you can add the sequence to the middle of the mutagenic primer.\u00a0 This is option 2 in the recording. However if the insertion is longer- multiple amino acids &#8211; then the extra sequence is added to the 5&#8242; end of one of the primers. The gene specific parts of the primers are right next to each other, so there is no overlap between them, nor any nucleotides between them.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-large wp-image-1138\" style=\"font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primer-placement.png\" alt=\"\" width=\"343\" height=\"113\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primer-placement.png 343w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primer-placement-300x99.png 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primer-placement-65x21.png 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primer-placement-225x74.png 225w\" sizes=\"auto, (max-width: 343px) 100vw, 343px\" \/><\/p>\n<div id=\"h5p-70\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-70\" class=\"h5p-iframe\" data-content-id=\"70\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Primer placement 1\"><\/iframe><\/div>\n<\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1137\" style=\"font-size: 1em;font-style: italic\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/econd-primer-placement.png\" alt=\"\" width=\"343\" height=\"112\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/econd-primer-placement.png 343w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/econd-primer-placement-300x98.png 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/econd-primer-placement-65x21.png 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/econd-primer-placement-225x73.png 225w\" sizes=\"auto, (max-width: 343px) 100vw, 343px\" \/><\/p>\n<div id=\"h5p-71\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-71\" class=\"h5p-iframe\" data-content-id=\"71\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Primer placement 2\"><\/iframe><\/div>\n<\/div>\n<p><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-2.ppt\">Click here for the powerpoint slides<\/a>.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-2\" title=\"Chapter 16 part 2 SIte directed mutagenesis using PCR\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/sfcthBxFN0o?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<hr style=\"height: 5px;border-top: solid black\" \/>\n<h2><a id=\"B_fusion\"><\/a>B. Fusion PCR:<\/h2>\n<p>Fusion PCR is a PCR-based method of combining two sequences. It works well in some instances; we\u2019ve done this in BISC 357 in the past with variable success. It requires careful pipetting and more time spent purifying the products etc than we really have time for in the class.<\/p>\n<p>In this method, you PCR amplify the two pieces you want to combine with some overlapping sequence on the primers- similar to how it is done with SLIC. The image below shows the two PCR products generated in preparation for fusion PCR. The first amplicon (blue) has a reverse primer that has a 5&#8242; end complementary to the forward primer of the second amplicon (red).\u00a0 The two PCR reactions are amplified separately, and when the first one is complete, it has sequence at its 3&#8242; end that matches the 5&#8242; end of the second amplicon, shown with colour coding.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-large wp-image-927\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-1024x430.jpg\" alt=\"\" width=\"1024\" height=\"430\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-1024x430.jpg 1024w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-300x126.jpg 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-768x322.jpg 768w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-1536x644.jpg 1536w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-2048x859.jpg 2048w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-65x27.jpg 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-225x94.jpg 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/fusion-PCR-start-350x147.jpg 350w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p>The two pieces are amplified separately and then the products are column purified, which is essential because we need to get rid of all the primers that are in the reactions. If there is a lot of background, we might gel purify the products that are the correct size to enhance the likelihood of success.<\/p>\n<p>Then we combine the products of the two PCR reactions together in equal amounts, in a tube with primers specific for the forward end of the first product (1F) and the reverse end of the other (2R). The two products can bind to each other due to the overlapping sequences generated on the amplicon, and there are two orientations where this is possible. \u00a0In one orientation nothing will happen because the recessed ends are 5\u2019 ends. However, in the other orientation the recessed ends are 3\u2019 ends and in the first cycle, Taq polymerase can extend these as it would any primer &#8211; generating strands of DNA that now include the combined fragments.<\/p>\n<p>The image below shows this. The strands of the products are labeled A through D for the purposes of the explanation. There are four ways that the DNA strands can bind. A and B can bind and C and D can bind. These strands can&#8217;t be extended. Strand C and B can bind each other as well, due to the overlapping complementary region.\u00a0 If they do, as shown below, no extension of the strands can occur as the recessed ends are both 5&#8242; ends. Finally strands A and D can also bind each other due to their overlapping region. In this case, the recessed ends are 3&#8242; ends which can be extended by Taq.\u00a0 The result will be that the A and D strands will be extended to generate the full length desired product.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-large wp-image-928\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-1024x692.jpg\" alt=\"\" width=\"1024\" height=\"692\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-1024x692.jpg 1024w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-300x203.jpg 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-768x519.jpg 768w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-1536x1039.jpg 1536w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-2048x1385.jpg 2048w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-65x44.jpg 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-225x152.jpg 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Fusion-PCR-final-350x237.jpg 350w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p>In the next cycle the primers 1F and 2R that match the ends of the combined fragment can make the complementary strands.\u00a0 This generates a PCR product that has fused the two amplicons from the first reaction into a single larger amplicon. The alignment of the A and D strands of DNA will not happen frequently in the PCR reaction but even if it occurs occasionally, that will be enough to generate a fusion product. This is the power of PCR.\u00a0<span style=\"background-color: #ffff99\"><em> Study tip: You should draw this out with a few nucleotides indicating the &#8220;overlap&#8221; sequence to ensure you understand it.<\/em><\/span><\/p>\n<p><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-3.ppt\">Click here for the powerpoint slides<\/a>.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-3\" title=\"Chapter 16 part 3 PCR fusion\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/wDo5KqXe2VE?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<hr style=\"height: 5px;border-top: solid black\" \/>\n<h2><a id=\"C_PCR\"><\/a>C. PCR on transgenic organisms:<\/h2>\n<h3><a id=\"C1_confirmation\"><\/a>C-1. Confirmation of the presence of the foreign DNA<\/h3>\n<p>If we have generated organisms that we think are transgenic, we want to confirm that the transgene is incorporated in the genome.\u00a0 We can use gene specific primers that should recognize only the introduced DNA. These will only generate a product if the transgene is present. Clearly, it cannot be a gene that naturally occurs in the organism.\u00a0 And the positive and negative controls are really important.\u00a0 If we don\u2019t see a band, we want to be sure that this is a real negative result \u2013 that the organism really doesn\u2019t have our transgene. Which control is the most important one to reassure us that we COULD have amplified the band if the gene was present?\u00a0 If we do see a band, we want to be sure this band was amplified from the template we added and not some contaminating DNA. Which control lets us feel confident that our bands indicate a real positive result rather than a contaminant?<\/p>\n<div id=\"h5p-72\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-72\" class=\"h5p-iframe\" data-content-id=\"72\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Confirmation PCR 1\"><\/iframe><\/div>\n<\/div>\n<hr \/>\n<h3><a id=\"C2_determining\"><\/a>C-2. Determining the position of the transgene<\/h3>\n<p>We can use<strong><span style=\"color: #0000ff\"> inverse PCR<\/span><\/strong> to determine where in the genome our foreign DNA is inserted. We use the sequence we do know to identify the sequence we don\u2019t know but want to know.<\/p>\n<p>We start by cutting the genomic DNA with a restriction enzyme that we know does not cut inside our construct. This cuts the genome into many pieces. Then a ligation is performed in a very large volume to ensure that the DNA is very dilute. In this case, the closest free end that the DNA can ligate with is on the same molecule. This favours circularization of the DNA pieces.<\/p>\n<p>Then PCR is performed using primers that recognize the edges of the construct and are directed outward. The product that is made consists of the sequence to either side of the construct. We only need perhaps 30 or 40 nucleotides of sequence to pinpoint unique sites in the genome unless our construct is in the midst of a repeat sequence.<\/p>\n<p><em>\u00a0<\/em><\/p>\n<hr \/>\n<h3><a id=\"C3_checking\"><\/a>C-3. Checking for homozygosity or heterozygosity<\/h3>\n<p>When we have transgenic organisms, we want to know whether they are homozygous or heterozygous for the construct. In this case we use our information obtained from part C-2 and we design a primer set in which one forward primer recognizes the insert and the other forward primer recognizes sequence upstream of the insert. The reverse primer recognizes sequence downstream of the insert. Depending on whether or not the insert is in the DNA, you will either get a band from the combination of the insert-specific primer plus the reverse primer, or from the upstream specific primer combined with the reverse primer. It is important that:<\/p>\n<ol>\n<li>The band sizes for each pair of primers is different and easy to distinguish.<\/li>\n<li>The insert is so large that if it is present in the DNA, the second forward primer will be unable to generate a band with the reverse primer.<\/li>\n<\/ol>\n<p>In the image below, the three primers are shown on the upper chromosome, which has the insert (in orange) and the two primers are shown on the lower chromosome, which does not have the insert. The expected band sizes are just an example. The insert is not to scale. Assume that it is about 8-`15 kb in length.<\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-907\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous.jpg\" alt=\"\" width=\"1941\" height=\"695\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous.jpg 1941w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-300x107.jpg 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-1024x367.jpg 1024w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-768x275.jpg 768w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-1536x550.jpg 1536w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-65x23.jpg 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-225x81.jpg 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Primers-for-heterozygous-homozygous-350x125.jpg 350w\" sizes=\"auto, (max-width: 1941px) 100vw, 1941px\" \/><\/p>\n<p>When the PCRs are run on a gel, the band sizes tell us whether the individual is homozygous for the normal chromosome (1.5 kb band), homozygous for the inserted chromosome (1 kb), or heterozygous (one of each type of chromosome, one 1.5 and one 1.). Please ensure that you understand the image above and the gel schematic below.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-924 alignleft\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous.jpg\" alt=\"\" width=\"347\" height=\"323\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous.jpg 795w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous-300x280.jpg 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous-768x716.jpg 768w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous-65x61.jpg 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous-225x210.jpg 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Gel-heterozygous-homozygous-350x326.jpg 350w\" sizes=\"auto, (max-width: 347px) 100vw, 347px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Here are some images for the self-test questions below. The first shows an image of a gene on a chromosome, one version with no inserted transgene and one version with an inserted transgene. Three primers are shown: F1 is the forward primer that recognizes the F&#8217; end of the gene and R is the reverse primer that recognizes the 3&#8242; end of the gene. F2 is a forward primer that recognizes the transgene. Please note that the schematic is not to scale. The GOI is about 1.5 kb in length, while the transgene is about 10 kb in length.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1146 alignleft\" style=\"font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers.png\" alt=\"\" width=\"444\" height=\"148\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers.png 444w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers-300x100.png 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers-65x22.png 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers-225x75.png 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/positions-of-primers-350x117.png 350w\" sizes=\"auto, (max-width: 444px) 100vw, 444px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Below are images that show the chromosome constitutions of three different individuals. Please answer the questions below each image, about the individual shown in that image.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1144\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert.png\" alt=\"\" width=\"389\" height=\"69\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert.png 389w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert-300x53.png 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert-65x12.png 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert-225x40.png 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-for-insert-350x62.png 350w\" sizes=\"auto, (max-width: 389px) 100vw, 389px\" \/><\/p>\n<div id=\"h5p-75\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-75\" class=\"h5p-iframe\" data-content-id=\"75\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Transgene detection 2\"><\/iframe><\/div>\n<\/div>\n<div id=\"h5p-76\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-76\" class=\"h5p-iframe\" data-content-id=\"76\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Transgene detection 3\"><\/iframe><\/div>\n<\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1145\" style=\"text-align: initial;font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal.png\" alt=\"\" width=\"383\" height=\"72\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal.png 383w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal-300x56.png 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal-65x12.png 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal-225x42.png 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Homozygous-normal-350x66.png 350w\" sizes=\"auto, (max-width: 383px) 100vw, 383px\" \/><\/p>\n<div id=\"h5p-74\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-74\" class=\"h5p-iframe\" data-content-id=\"74\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Transgene detection 0\"><\/iframe><\/div>\n<\/div>\n<div id=\"h5p-73\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-73\" class=\"h5p-iframe\" data-content-id=\"73\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Transgene detection 1\"><\/iframe><\/div>\n<\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1143\" style=\"font-size: 1em\" src=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous.png\" alt=\"\" width=\"388\" height=\"74\" srcset=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous.png 388w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous-300x57.png 300w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous-65x12.png 65w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous-225x43.png 225w, https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Heterozygous-350x67.png 350w\" sizes=\"auto, (max-width: 388px) 100vw, 388px\" \/><\/p>\n<div id=\"h5p-77\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-77\" class=\"h5p-iframe\" data-content-id=\"77\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Transgene detection 4\"><\/iframe><\/div>\n<\/div>\n<div id=\"h5p-78\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-78\" class=\"h5p-iframe\" data-content-id=\"78\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Transgene detection 5\"><\/iframe><\/div>\n<\/div>\n<p><strong><span style=\"color: #800000\">Please note t<\/span><\/strong><strong style=\"text-align: initial;font-size: 1em\"><span style=\"color: #800000\">hat there is an error in the recording for iPCR. The sequencing primers are the same ones used in the PCR.\u00a0\u00a0<\/span><\/strong><\/p>\n<p><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-content\/uploads\/sites\/1093\/2020\/08\/Chapter-16-Common-applications-of-PCR-part-4.ppt\">Click here for the powerpoint slides<\/a>.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-4\" title=\"Chapter 16 final, use of PCR to characterize transgenic orga\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/aEEV2EpuV7E?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<p style=\"text-align: left\"><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-15-alternative-methods-of-cloning-3-slic\/\">Previous (Chapter 15)<\/a><span style=\"float: right\"><a href=\"https:\/\/pressbooks.bccampus.ca\/kathleef\/chapter\/chapter-17-introducing-dna-into-cells\/\">Next (Chapter 17)<\/a><\/span><\/p>\n","protected":false},"author":1046,"menu_order":19,"template":"","meta":{"pb_show_title":"on","pb_short_title":"Other uses of PCR","pb_subtitle":"","pb_authors":[],"pb_section_license":"cc-by-nc"},"chapter-type":[47],"contributor":[],"license":[55],"class_list":["post-91","chapter","type-chapter","status-publish","hentry","chapter-type-standard","license-cc-by-nc"],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/chapters\/91","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/wp\/v2\/users\/1046"}],"version-history":[{"count":26,"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/chapters\/91\/revisions"}],"predecessor-version":[{"id":1528,"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/chapters\/91\/revisions\/1528"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/chapters\/91\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/wp\/v2\/media?parent=91"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/pressbooks\/v2\/chapter-type?post=91"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/wp\/v2\/contributor?post=91"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/kathleef\/wp-json\/wp\/v2\/license?post=91"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}