A PCR-RFLP analysis was performed to identify PTC tasters in a population. The taster allele sequence included a palindromic sequence recognized by a restriction enzyme, whereas the non-taster allele did not due to a SNP in the sequence. The gel shows the results of the analysis from 100 individuals. The numbers above the gel lanes represent the number of individuals with each genotype. 33 52 15 Based on the results from the gel, what is the frequency of the taster allele in this population? 0.0387 0.41 0.33 0.685 0.59 0.52 0.315 0.0574 Screenshot

After you design the PCR primers, you run the PCR on fluid from the patient’s nasal swab. Next, you need to evaluate the results. PCR makes billions of copies of just one sequence in a sample. Since you know the sequence, you also know the length (number of nucleotides) of the region you copied. There are about 130 nucleotides in the N gene fragment. This is typically stated as 130 base pairs. How can you visualize DNA and estimate its size? Load the DNA sample into an agarose gel (similar in consistency to jello) and apply an electric current to the gel. The DNA is charged and will move through the gel. The longer the DNA fragment, the more slowly it moves. The DNA is visualized by adding a fluorescent dye to your sample that sticks to DNA. When you look at the gel under UV light, the DNA should glow. What is the charge of a DNA molecule? Based on #1, would you expect DNA to be drawn to the (+) or (-) electrode of the gel electrophoresis chamber?

In lane 1, a size standard was loaded, which contained a mix a DNA fragments known to be 1000 bp, 700 bp, 500 bp, 200 bp, and 100 bp.  In lanes 2-4, human samples the have undergone PCR reactions with PV92 primers have been completed and loaded into these wells. When the gel was run and stained, the following photograph of the gel was taken. Click on the lane (2-4) which shows a result consistent with a genotype of +/+ (homozygous for having the PV92 Alu insertion).

Think about the function of the primers in a PCR that is designed to amplify a specific sequence, and about the temperatures of the PCR cycle. After considering these two points, give two reasons why 4-nucleotide long primers are not appropriate for PCR and explain.

fellow lab worker brings you DNA containing what might be a similar gene in Leopard Geckos (XG). She asks you to see if you can amplify it using the same primers you used in frogs and the Bearded Dragon. You run the PCR and then analyze the product by running the DNA on an agarose gel. As a control, you run out the PCR product you amplified in Bearded Dragons and a DNA “ladder” of DNA pieces of known sizes. The gel results are shown below. Marker = DNA ladder; Lane A = Bearded Dragon PCR product; Lane B = Leopard Gecko PCR results. In the box below, determine the sizes of the PCR products shown in Lanes A & B. Size of Bearded Dragon PCR product: ______________________________  Sizes of Leopard Gecko PCR products: ______________________ yes or No - based on the results shown in the gel above – would you say the frog PCR primers for gene X amplified the same gene in the Bearded Dragon?

Answer the question in the photo

In a transformation experiment involving a recipientbacterial strain of genotype a- b-, the following resultswere obtained. What can you conclude about the locationof the a and b genes relative to each other?                                Transformants (%)Transforming DNA    a+ b-    a-b+       a+b+a+b-                            3.1       1.2         0.04a+b- and a-b+            2.4       1.4         0.03

In the following "gene library" cloning experiment Digested genomic DNA AmpR gene TCR gene TCR is tetracycline resistant marker, AmpR is ampicillin resistant marker and BamHI is the unique restriction enzyme on plasmid. A PhD student digests/cuts the plasmids with BamHI restriction enzyme and the genomic DNA with EcoRI restriction enzyme. After performing the cloning experiment and obtaining colonies on a selection plate, the obtained cells will be ..... (Hint: this question is even more challenging; the PhD student was later demoted to an MSc student). a) resistant to ampicillin and tetracycline b) sensitive to tetracycline and ampicillin c) resistant to tetracycline and sensitive to ampicillin d) resistant to ampicillin and sensitive to tetracycline e) sensitive to ampicillin and tetracycline BamHI