Genotyping

Genotyping Online Assignment

1. (1 pt) What was the purpose of isolating and sequencing bacterial DNA in the virtual lab? (Of course, the purpose is for you to learn something about genotyping, but I would like you to identify the end result achieved in the virtual lab.)

Some genes vary between species, but not between individual bacterium. We use this to find the closest match of DNA to identify our species. Attached our the samples and the correctly identified species they were.

2. a. (1 pt) What gene was targeted for PCR and sequencing in the virtual lab?

16S rRNA gene

b. (1 pt) Why is this gene appropriate for identifying bacteria?

This is "universal," because the sequences are very similar among all bacterial species. Universal primers bind to the similar regions of genes so that they can be used to copy DNA from a many species. The variable regions then allow us to identify the different species.

3. (1 pt) Why is the PCR step of the procedure important?

PCR allows for many copies of a gene you want to sequence in a shorter period of time and allows for less error.

4. (1 pt) How does using fluorescently-labeled nucleotides help with finding the sequence of the DNA? (Hint: A simple answer is just fine.)

Fluorescently-labeled nucleotides help distinguish between the A, T ,G, C nucleotides so its easier to separate the individual pieces and identify the nucleotide. A laser beam excites the fluorescent markers, and optical detectors detect the color of the fluorescence. We read the sequence based on their fluorescence as they pass through the laser beam and construct the DNA sequence.

5. (1 pt) Identify a specific step of the procedure and explain ONE thing that could have gone wrong to result in unreadable DNA sequence.

One step that could have led to an unreadable DNA sequence could have been the gel purifying of the DNA. Running the gel confirms the PCR worked and we should have a negative control, a positive control with a known DNA...