Isolation of DNA from Food Products
Purpose: This activity is a simpler form of the laboratory procedure practiced
routinely in genetics labs around the world. This is the way to obtain DNA to
study for whatever a scientist may wish to learn about a plant or animal.
1. Students will be able to perform simple DNA isolation with basic lab
2. Students will investigate the pervasive nature of DNA while isolating
the DNA from three different plant materials.
3. Qualitative analytic skill and reasoning will be exhibited in the final
reports to be handed in by the students.
DNA is easily separated from dense fruits and vegetables which can be
readily liquefied. The three fruits and vegetables used here (bananas,
strawberries and onions) are not the only materials which will work with this
technique, so in an inquiry class, different fruits/vegetables may be tried. A
greater degree of ripeness appears to yield the best results, so grocers are often
good sources for produce which has become too ripe to sell. It is important,
however, to avoid moldy products, as these are potential allergens and in an
actual genetics lab, would pollute the DNA.
The produce used should be blended well in the blender to produce the
optimal amount of juice. Since onions have a strong aroma, it is prudent to pick
a nice day for this activity, in which the windows may be open or the activity may
be carried on outside.
Separate the students into groups. This can be done in numbers divisible
by three. Each group will have one type of produce, and will be responsible for
observing the results of two other groups who have used the two other types of
produce. This way, each group actually performs the lab, and then may use
others data to compare with their own.
The lab report to be turned in by each student, or group of students,
a) the purpose of the lab (to isolate DNA from plant material).
b) the materials used.
c) the method which was used by the group (not a copy of the lab
d) data taken during the lab (color, texture, what happened when the
reagents were added, what the end result looked like, how this compared
to the other groups isolated DNA).
e) the conclusion (where the DNA came from, what occurred to allow it to
be isolated, a comparison of the groups DNA with DNA from other
groups, future inquiry).