Posted: June 21st, 2015

The image shows the results of analyzing restriction enzyme digested PCR reactions from seven individuals using gel electrophoresis.

The image shows the results of analyzing restriction enzyme digested PCR reactions from seven individuals using gel electrophoresis.  Samples were loaded at the top of the gel shown below and run towards the bottom.  The lanes on the gel are numbered at the top.  Lane 1 contains what is called a “DNA ladder”.  This is a mix of DNA of known sizes that we purchase and run as a standard, or ruler, on the side of the gel.  I have labeled the size of two of these “ladder rungs” or standards.  You can use these standards to get an idea of the size of the bands in lanes 2-8.  Each of these lanes represents one of seven individuals that have been tested.

Use the gel to determine the genotypes of individuals 2-8 and enter them in the following assessment assignment.  I will also ask you to explain how you were able to determine the genotypes from the information on this gel.  In the last module you determined the sizes of the DNA fragments produced by the restriction enzyme digest and one of those was smaller than 100 basepairs.  That small DNA band is hard to see on the gel above, so don’t get confused if it does not look like it is there.  Focus on the two larger bands to determine if the DNA is being cut or not.
Based on the direction answer the following questions.
1.
Explain how you were able to determine the genotypes of each individual from the information on this gel.

2.
What is the genotype of individual 2?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygote
3.
What is the genotype of individual 3?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygote
4.
What is the genotype of individual 4?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygote
5.
What is the genotype of individual 5?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygote
6.
What is the genotype of individual 6?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygote
7.
What is the genotype of individual 7?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygote
8.
What is the genotype of individual 8?
A) Homozygous taster
B) Homozygous non-taster
C) Heterozygot