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To measure genes, it is
necessary to obtain a small sample of an individual's DNA. A simple,
painless way to do this is to brush the inside of the mouth with a
cotton-tipped swab. Cells that line the inside of the cheek (called
'buccal' cells) are shed constantly (as new cells are born) and these
cells will be picked up by the cotton swab. DNA is then extracted
from the buccal cells.
Below
are a series of pictures that show the swabbing process. Before beginning,
subjects must abstain from eating or drinking (especially coffee) for 30 min
prior to swabbing. We start by having the subject wash their hands thoroughly
and rinsing their mouth twice with water.
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1. The swabs come
pre-packaged in a sterile plastic tube. A gentle twist breaks the
seal and opens the plastic tube. |
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2. Each tube
contains two sterile swabs, one for each cheek. |
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3. The swab is held
in middle with the left hand. The tip of the swab is then placed firmly
on the inside surface of the cheek and rolled with the right hand.
The swab is rolled vigorously on the inside of the cheek 30 times, while moving it
over the entire surface of the cheek. This process is repeated
with the other swab for the other cheek. A left-handed individual
may prefer to 'hold' with the right hand and 'roll' with the
left. |
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4. When swabbing is
complete, the swabs are returned to the plastic tubing and sealed.
Each subject is given an numeric code that is placed on the tube.
All subsequent handling and processing of the DNA is done without
knowledge of the subject's identity. |
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