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Labs Quiz 2

Labs Quiz 2

Q Question 1 2 / 2 pts Please consider the gel electrophoresis image and the DNA ladder. In the gel, the DNA ladder was loaded in lane 1 (far left), and the PCR product samples were loaded in lanes 2 through 8. Question 2 2 / 2 pts For your BLAST search on the DNA sequence you chose, what species did your sequence most closely align with, and with what percent identity? Question 3 2 / 2 pts Please upload an image (see "embed image" icon in the submission field) of your phylogenetic tree produced from your Clustal analysis of the class sequences. 1) In a sentence or two, what does a phylogenetic tree tell us? 2) Considering the species you did your BLAST search on, to what species on the tree is yours most closely related to? 3) To what species is it most distantly related to?

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1.1. In lane 8 the size of the DNA fragment is 1.5 kb approximately. The PCR produced a product of that size because the amplified gene is having 1.5 kb length. 2. In lane 7 there is no PCR product, it means that the PCR reaction did not amplify any DNA. Many suggestions can be the reason behind this observation, we can state for example the absence of DNA in the PCR mix, the primers could not bind to any region in the DNA (not specific, for example using bacterial primers on fungi DNA sample). This also can happen when the quality of the DNA is very low (for example bad storage).